diff --git a/.githooks/pre-commit b/.githooks/pre-commit
index b9202975..1cfc9f32 100755
--- a/.githooks/pre-commit
+++ b/.githooks/pre-commit
@@ -3,3 +3,4 @@ set -euo pipefail
 ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 "$ROOT/scripts/verify-no-secrets.sh" --staged
 "$ROOT/scripts/generate-connector-contract.swift" --check
+"$ROOT/scripts/generate-script-exec-contract.swift" --check
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 755f87f3..96feb39e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -5,7 +5,8 @@ Thank you for your interest in contributing. Please read the [Code of Conduct](C
 ## Requirements
 
 - **macOS** with **Xcode 27** (Swift 6.4+)
-- **Docker Desktop** (Python guest runtime, web crawler, and file extractor images)
+- **Docker Desktop** (Go worker image for guests, web crawler, and file extractor)
+- **Go 1.27.1+** (`brew install go`) for local diagnostics; guest compile runs in Docker
 - Apple Developer account for code signing
 
 ## Getting started
diff --git a/SECURITY.md b/SECURITY.md
index 470cbe9b..02096041 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -18,7 +18,7 @@ We will acknowledge receipt and work on a fix before public disclosure when poss
 Derrick runs LLM agents with tools on the user's Mac. The design assumes:
 
 - **Untrusted model output** — tools and scripts are gated before execution.
-- **Untrusted guest code** — Python plugins/scripts run in Docker with no network; the host performs HTTP.
+- **Untrusted guest code** — Go plugins/scripts compile and run in Docker with no network; the host performs HTTP.
 - **Untrusted remote content** — fetched HTML and tool output are sanitized before display.
 - **Secrets stay on the host** — API keys and connector tokens live in Keychain or local `.env` (dev only); they are not injected into guest containers.
 
@@ -26,7 +26,7 @@ Derrick runs LLM agents with tools on the user's Mac. The design assumes:
 
 | Layer | Mechanism |
 |-------|-----------|
-| Script execution | Docker `--network none`, static Python verifier, LLM script reviewer |
+| Script execution | Docker `--network none`, static Go verifier, in-container compile, LLM script reviewer |
 | Network egress | Host HTTP client, egress blacklist, user approval for new destinations |
 | Plugins | Factory build + review; hop-limited `http.request`; Keychain-attached auth |
 | Inter-process | Code-signed XPC peers, HMAC-signed service messages (release: Keychain secret) |
diff --git a/THIRD_PARTY_NOTICES.md b/THIRD_PARTY_NOTICES.md
index d7da35c2..8d30ce1e 100644
--- a/THIRD_PARTY_NOTICES.md
+++ b/THIRD_PARTY_NOTICES.md
@@ -23,7 +23,7 @@ Derrick integrates with user-configured APIs. You supply your own keys and are s
 
 ## Runtime
 
-- **Docker Desktop** — script and plugin execution use the `python:3.14.7` guest image (see `docs/adr-swift-script-runtime.md` for superseded Swift guest notes).
+- **Docker Desktop** — script and plugin execution use the `derrick-worker:go-v1` guest image.
 
 ## Project license
 
diff --git a/docker/guest-runtime/Dockerfile b/docker/guest-runtime/Dockerfile
deleted file mode 100644
index 5c99ce18..00000000
--- a/docker/guest-runtime/Dockerfile
+++ /dev/null
@@ -1,15 +0,0 @@
-# Offline guest runtime for script_exec and plugin.invoke (Python primary).
-# Build: docker build -f docker/guest-runtime/Dockerfile -t derrick-guest-runtime:python-v1 .
-FROM python:3.14.7
-
-RUN useradd --create-home --uid 10001 guest
-
-# uv — fast, lockfile-friendly dependency installs inside the guest image.
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
-
-WORKDIR /home/guest
-USER guest
-
-# Guests run with --network none; deps are baked into the image or installed at build time.
-ENV UV_LINK_MODE=copy \
-    PYTHONUNBUFFERED=1
diff --git a/docker/worker/.dockerignore b/docker/worker/.dockerignore
new file mode 100644
index 00000000..b01fe143
--- /dev/null
+++ b/docker/worker/.dockerignore
@@ -0,0 +1,3 @@
+**/.git
+**/.build
+**/node_modules
diff --git a/docker/worker/Dockerfile b/docker/worker/Dockerfile
new file mode 100644
index 00000000..0e11fc1a
--- /dev/null
+++ b/docker/worker/Dockerfile
@@ -0,0 +1,33 @@
+# Unified Go worker image: web crawl, file extract (plugin guest binaries are copied per invoke).
+# Build: docker build -f docker/worker/Dockerfile -t derrick-worker:go-v1 .
+FROM golang:1.27.1 AS build
+
+WORKDIR /src
+COPY workers/go/go.mod workers/go/go.sum ./
+RUN go mod download
+COPY workers/go ./
+
+RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -ldflags="-s -w" -o /out/derrick-web-crawler ./cmd/derrick-crawler
+RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -ldflags="-s -w" -o /out/derrick-file-extractor ./cmd/derrick-file-extractor
+
+FROM debian:bookworm-slim
+
+LABEL derrick.worker.binaries="crawler,extractor"
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends poppler-utils ca-certificates \
+    && rm -rf /var/lib/apt/lists/* \
+    && useradd --create-home --uid 10001 worker
+
+COPY --from=build /usr/local/go /usr/local/go
+COPY --from=build /out/derrick-web-crawler /usr/local/bin/derrick-web-crawler
+COPY --from=build /out/derrick-file-extractor /usr/local/bin/derrick-file-extractor
+RUN mkdir -p /data/in /data/out && chown -R worker:worker /data
+
+ENV PATH=/usr/local/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+ENV GOROOT=/usr/local/go
+ENV GOTOOLCHAIN=local
+ENV CGO_ENABLED=0
+
+USER worker
+WORKDIR /home/worker
diff --git a/docs/Design.md b/docs/Design.md
index 6bcc9bf7..5a9171d9 100644
--- a/docs/Design.md
+++ b/docs/Design.md
@@ -10,4 +10,4 @@ This application is Protocol first. All major features must have a Protocol and
 
 ## Plugins
 - Plugins are using the Agent Plugin standard
-- Plugins run in the plugins docker containers as either Python or Go (Go is not yet supported)
+- Plugins and `script_exec` run in the unified Go worker Docker image (`derrick-worker:go-v1`)
diff --git a/master-todo.md b/master-todo.md
index c6e09ec3..9cd98b98 100644
--- a/master-todo.md
+++ b/master-todo.md
@@ -77,7 +77,7 @@ Open: binary convert (xlsx) has no “here is your file” UI yet. Do not delete
 Each `script_exec` / `plugin.invoke`:
 
 1. Wait for the offline queue (max 1).
-2. `docker create` a unique `derrick-guest-runtime-<uuid>` from `python:3.14.7`.
+2. `docker create` a unique `derrick-guest-runtime-<uuid>` from `derrick-worker:go-v1`.
 3. Run until the host hop loop is done (terminal envelope, error, or in-use lease TTL).
 4. `docker rm -f` immediately — that is “I’m done.”
 5. Release the queue slot so the next script can create at once.
diff --git a/packages/DBRepository/Sources/DBRepository/DBRepositoryNews.swift b/packages/DBRepository/Sources/DBRepository/DBRepositoryNews.swift
deleted file mode 100644
index 1490c869..00000000
--- a/packages/DBRepository/Sources/DBRepository/DBRepositoryNews.swift
+++ /dev/null
@@ -1,157 +0,0 @@
-import Foundation
-import SQLite3
-import Structure
-
-public extension DBRepository {
-    func upsertNewsReader(_ spec: NewsReaderSpec) throws {
-        let topicsData = try JSONEncoder().encode(spec.topics)
-        let sourcesData = try JSONEncoder().encode(spec.sources)
-        let topics = String(data: topicsData, encoding: .utf8) ?? "[]"
-        let sources = String(data: sourcesData, encoding: .utf8) ?? "[]"
-        try withDatabaseHandle { handle in
-            try Self.execute("""
-            INSERT INTO news_readers (
-                id, name, topics_json, sources_json, mode, max_count, schedule,
-                last_error, last_fetched_at, created_at, updated_at
-            ) VALUES (
-                \(quoted(spec.id)),
-                \(quoted(spec.name)),
-                \(quoted(topics)),
-                \(quoted(sources)),
-                \(quoted(spec.mode.rawValue)),
-                \(spec.maxCount),
-                \(quoted(spec.schedule.rawValue)),
-                \(sqlValue(spec.lastError)),
-                \(sqlValue(spec.lastFetchedAt.map { Self.iso8601Formatter().string(from: $0) })),
-                \(quoted(Self.iso8601Formatter().string(from: spec.createdAt))),
-                \(quoted(Self.iso8601Formatter().string(from: spec.updatedAt)))
-            )
-            ON CONFLICT(id) DO UPDATE SET
-                name = excluded.name,
-                topics_json = excluded.topics_json,
-                sources_json = excluded.sources_json,
-                mode = excluded.mode,
-                max_count = excluded.max_count,
-                schedule = excluded.schedule,
-                last_error = excluded.last_error,
-                last_fetched_at = excluded.last_fetched_at,
-                updated_at = excluded.updated_at;
-            """, on: handle)
-        }
-    }
-
-    func listNewsReaders() throws -> [NewsReaderSpec] {
-        try withDatabaseHandle { handle in
-            let sql = """
-            SELECT id, name, topics_json, sources_json, mode, max_count, schedule,
-                   last_error, last_fetched_at, created_at, updated_at
-            FROM news_readers
-            ORDER BY updated_at DESC;
-            """
-            var statement: OpaquePointer?
-            guard sqlite3_prepare_v2(handle, sql, -1, &statement, nil) == SQLITE_OK, let statement else {
-                throw Self.sqliteError(handle: handle, fallback: "Failed to list news readers.")
-            }
-            defer { sqlite3_finalize(statement) }
-            var rows: [NewsReaderSpec] = []
-            while sqlite3_step(statement) == SQLITE_ROW {
-                rows.append(try decodeNewsReader(statement: statement))
-            }
-            return rows
-        }
-    }
-
-    func deleteNewsReader(id: String) throws {
-        try withDatabaseHandle { handle in
-            try Self.execute("DELETE FROM news_readers WHERE id = \(quoted(id));", on: handle)
-        }
-    }
-
-    func replaceNewsItems(readerID: String, items: [NewsItem]) throws {
-        try withDatabaseHandle { handle in
-            try Self.withImmediateTransaction(on: handle) {
-                try Self.execute("DELETE FROM news_items WHERE reader_id = \(quoted(readerID));", on: handle)
-                for item in items {
-                    try Self.execute("""
-                    INSERT INTO news_items (
-                        id, reader_id, title, source_url, source_label, summary, published_at, fetched_at
-                    ) VALUES (
-                        \(quoted(item.id)),
-                        \(quoted(item.readerID)),
-                        \(quoted(item.title)),
-                        \(quoted(item.sourceURL)),
-                        \(quoted(item.sourceLabel)),
-                        \(sqlValue(item.summary)),
-                        \(sqlValue(item.publishedAt.map { Self.iso8601Formatter().string(from: $0) })),
-                        \(quoted(Self.iso8601Formatter().string(from: item.fetchedAt)))
-                    );
-                    """, on: handle)
-                }
-            }
-        }
-    }
-
-    func listNewsItems(readerID: String) throws -> [NewsItem] {
-        try withDatabaseHandle { handle in
-            let sql = """
-            SELECT id, reader_id, title, source_url, source_label, summary, published_at, fetched_at
-            FROM news_items
-            WHERE reader_id = \(quoted(readerID))
-            ORDER BY fetched_at DESC;
-            """
-            var statement: OpaquePointer?
-            guard sqlite3_prepare_v2(handle, sql, -1, &statement, nil) == SQLITE_OK, let statement else {
-                throw Self.sqliteError(handle: handle, fallback: "Failed to list news items.")
-            }
-            defer { sqlite3_finalize(statement) }
-            var rows: [NewsItem] = []
-            while sqlite3_step(statement) == SQLITE_ROW {
-                rows.append(try decodeNewsItem(statement: statement))
-            }
-            return rows
-        }
-    }
-
-    private func decodeNewsReader(statement: OpaquePointer) throws -> NewsReaderSpec {
-        func text(_ index: Int32) -> String {
-            String(cString: sqlite3_column_text(statement, index))
-        }
-        func optionalText(_ index: Int32) -> String? {
-            sqlite3_column_type(statement, index) == SQLITE_NULL ? nil : text(index)
-        }
-        let topics = (try? JSONDecoder().decode([String].self, from: Data(text(2).utf8))) ?? []
-        let sources = (try? JSONDecoder().decode([NewsSource].self, from: Data(text(3).utf8))) ?? []
-        return NewsReaderSpec(
-            id: text(0),
-            name: text(1),
-            topics: topics,
-            sources: sources,
-            mode: NewsReaderMode(rawValue: text(4)) ?? .list,
-            maxCount: Int(sqlite3_column_int(statement, 5)),
-            schedule: NewsReaderSchedule(rawValue: text(6)) ?? .off,
-            lastError: optionalText(7),
-            lastFetchedAt: optionalText(8).flatMap { Self.iso8601Formatter().date(from: $0) },
-            createdAt: Self.iso8601Formatter().date(from: text(9)) ?? .now,
-            updatedAt: Self.iso8601Formatter().date(from: text(10)) ?? .now
-        )
-    }
-
-    private func decodeNewsItem(statement: OpaquePointer) throws -> NewsItem {
-        func text(_ index: Int32) -> String {
-            String(cString: sqlite3_column_text(statement, index))
-        }
-        func optionalText(_ index: Int32) -> String? {
-            sqlite3_column_type(statement, index) == SQLITE_NULL ? nil : text(index)
-        }
-        return NewsItem(
-            id: text(0),
-            readerID: text(1),
-            title: text(2),
-            sourceURL: text(3),
-            sourceLabel: text(4),
-            summary: optionalText(5),
-            publishedAt: optionalText(6).flatMap { Self.iso8601Formatter().date(from: $0) },
-            fetchedAt: Self.iso8601Formatter().date(from: text(7)) ?? .now
-        )
-    }
-}
diff --git a/packages/DBRepository/Sources/DBRepository/DatabaseSchema.swift b/packages/DBRepository/Sources/DBRepository/DatabaseSchema.swift
index 6e3121c2..b2aee8fa 100644
--- a/packages/DBRepository/Sources/DBRepository/DatabaseSchema.swift
+++ b/packages/DBRepository/Sources/DBRepository/DatabaseSchema.swift
@@ -2,7 +2,7 @@ import Foundation
 import Structure
 
 public enum DatabaseSchema {
-    public static let latestVersion = 8
+    public static let latestVersion = 9
 
     public static func migrationSQL(version: Int, isUp: Bool) throws -> String {
         let migrationName = String(format: "%04d_%@", version, migrationFileBaseName(for: version))
@@ -39,6 +39,8 @@ public enum DatabaseSchema {
             return "messaging_agent_handled"
         case 8:
             return "messaging_thread_default_profile"
+        case 9:
+            return "drop_news_readers"
         default:
             return "unknown"
         }
diff --git a/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0005_news_readers.up.sql b/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0005_news_readers.up.sql
index 6b4e5329..054ea0f3 100644
--- a/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0005_news_readers.up.sql
+++ b/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0005_news_readers.up.sql
@@ -6,6 +6,7 @@ CREATE TABLE IF NOT EXISTS news_readers (
     mode TEXT NOT NULL,
     max_count INTEGER NOT NULL,
     schedule TEXT NOT NULL,
+    summary_text TEXT,
     last_error TEXT,
     last_fetched_at TEXT,
     created_at TEXT NOT NULL,
diff --git a/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0009_drop_news_readers.down.sql b/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0009_drop_news_readers.down.sql
new file mode 100644
index 00000000..054ea0f3
--- /dev/null
+++ b/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0009_drop_news_readers.down.sql
@@ -0,0 +1,30 @@
+CREATE TABLE IF NOT EXISTS news_readers (
+    id TEXT PRIMARY KEY NOT NULL,
+    name TEXT NOT NULL,
+    topics_json TEXT NOT NULL DEFAULT '[]',
+    sources_json TEXT NOT NULL DEFAULT '[]',
+    mode TEXT NOT NULL,
+    max_count INTEGER NOT NULL,
+    schedule TEXT NOT NULL,
+    summary_text TEXT,
+    last_error TEXT,
+    last_fetched_at TEXT,
+    created_at TEXT NOT NULL,
+    updated_at TEXT NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS news_items (
+    id TEXT PRIMARY KEY NOT NULL,
+    reader_id TEXT NOT NULL,
+    title TEXT NOT NULL,
+    source_url TEXT NOT NULL,
+    source_label TEXT NOT NULL,
+    summary TEXT,
+    published_at TEXT,
+    fetched_at TEXT NOT NULL,
+    UNIQUE(reader_id, source_url),
+    FOREIGN KEY(reader_id) REFERENCES news_readers(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_news_items_reader
+    ON news_items(reader_id, fetched_at DESC);
diff --git a/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0009_drop_news_readers.up.sql b/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0009_drop_news_readers.up.sql
new file mode 100644
index 00000000..cbb5bff7
--- /dev/null
+++ b/packages/DBRepository/Sources/DBRepository/Resources/Migrations/0009_drop_news_readers.up.sql
@@ -0,0 +1,2 @@
+DROP TABLE IF EXISTS news_items;
+DROP TABLE IF EXISTS news_readers;
diff --git a/packages/DBRepository/Tests/DBRepositoryTests/DBNewsReaderTests.swift b/packages/DBRepository/Tests/DBRepositoryTests/DBNewsReaderTests.swift
deleted file mode 100644
index bbc475d1..00000000
--- a/packages/DBRepository/Tests/DBRepositoryTests/DBNewsReaderTests.swift
+++ /dev/null
@@ -1,60 +0,0 @@
-import XCTest
-import Structure
-@testable import DBRepository
-
-final class DBNewsReaderTests: XCTestCase {
-    func testNewsReaderRoundTripAndItems() async throws {
-        let repository = try makeRepository()
-        _ = try await repository.createEmptyDatabaseIfNeeded(username: "app-user", password: "app-secret")
-
-        let spec = NewsReaderSpec(
-            name: "Markets",
-            topics: ["Financial", "rates"],
-            sources: [NewsSource(label: "BBC", url: "https://feeds.bbci.co.uk/news/world/rss.xml")],
-            mode: .summaries,
-            maxCount: 10,
-            schedule: .daily
-        )
-        try await repository.upsertNewsReader(spec)
-        let listed = try await repository.listNewsReaders()
-        XCTAssertEqual(listed.count, 1)
-        XCTAssertEqual(listed[0].name, "Markets")
-        XCTAssertEqual(listed[0].topics, ["Financial", "rates"])
-        XCTAssertEqual(listed[0].mode, .summaries)
-
-        let item = NewsItem(
-            readerID: spec.id,
-            title: "Rates rise",
-            sourceURL: "https://example.com/rates",
-            sourceLabel: "BBC",
-            summary: "A summary"
-        )
-        try await repository.replaceNewsItems(readerID: spec.id, items: [item])
-        let items = try await repository.listNewsItems(readerID: spec.id)
-        XCTAssertEqual(items.count, 1)
-        XCTAssertEqual(items[0].sourceURL, "https://example.com/rates")
-
-        try await repository.deleteNewsReader(id: spec.id)
-        let remainingReaders = try await repository.listNewsReaders()
-        let remainingItems = try await repository.listNewsItems(readerID: spec.id)
-        XCTAssertTrue(remainingReaders.isEmpty)
-        XCTAssertTrue(remainingItems.isEmpty)
-    }
-
-    private func makeRepository() throws -> DBRepository {
-        let directory = FileManager.default.temporaryDirectory.appendingPathComponent(
-            UUID().uuidString,
-            isDirectory: true
-        )
-        try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)
-        return DBRepository(
-            configuration: DBRepositoryConfiguration(
-                applicationName: "ui",
-                databaseName: "derrick",
-                databaseDirectoryURL: directory,
-                username: "app-user",
-                password: "app-secret"
-            )
-        )
-    }
-}
diff --git a/packages/DBRepository/Tests/DBRepositoryTests/DBRepositoryTests.swift b/packages/DBRepository/Tests/DBRepositoryTests/DBRepositoryTests.swift
index a546a2c0..343da150 100644
--- a/packages/DBRepository/Tests/DBRepositoryTests/DBRepositoryTests.swift
+++ b/packages/DBRepository/Tests/DBRepositoryTests/DBRepositoryTests.swift
@@ -81,23 +81,9 @@ final class DBRepositoryTests: XCTestCase {
     func testSchemaUpgradeDoesNotWipeExistingRows() async throws {
         let repository = try makeRepository()
         _ = try await repository.createEmptyDatabaseIfNeeded(username: "app-user", password: "app-secret")
-        let artifact = Data("compiled".utf8)
-        let files: [String: Data] = [
-            "plugin.json": Data(#"{"name":"keep-me"}"#.utf8),
-            "app.derrick/runtime.json": Data(#"{"language":"swift"}"#.utf8),
-            "app.derrick/plugin.py": Data("print(\"[]\")".utf8),
-            "app.derrick/plugin": artifact,
-        ]
-        let release = PluginFactoryRelease(
+        let release = makeGoFactoryRelease(
             pluginID: "keep-me",
-            version: "1.0.0",
-            manifestJSON: String(decoding: files["plugin.json"] ?? Data(), as: UTF8.self),
-            runtimeJSON: String(decoding: files["app.derrick/runtime.json"] ?? Data(), as: UTF8.self),
-            guestSource: "print(\"[]\")",
-            compiledArtifact: artifact,
-            skillFiles: [:],
-            contentHash: PluginContentHash.hash(files: files),
-            reviewSummary: "approved"
+            manifestName: "keep-me"
         )
         try await repository.savePluginFactoryRelease(release)
         let url = await repository.databaseURL
@@ -108,7 +94,7 @@ final class DBRepositoryTests: XCTestCase {
 
         _ = try await repository.migrateSessionMemory(username: "app-user", password: "app-secret")
         XCTAssertEqual(try schemaVersion(at: url), DatabaseSchema.latestVersion)
-        XCTAssertTrue(try tableExists(named: "news_readers", at: url))
+        XCTAssertFalse(try tableExists(named: "news_readers", at: url))
         XCTAssertTrue(try tableExists(named: "agent_profiles", at: url))
         XCTAssertTrue(try tableExists(named: "messaging_agent_handled", at: url))
         let loaded = try await repository.pluginFactoryRelease(pluginID: "keep-me", version: "1.0.0")
@@ -119,25 +105,11 @@ final class DBRepositoryTests: XCTestCase {
     func testApprovedPluginFactoryReleasePersistsAndVerifies() async throws {
         let repository = try makeRepository()
         _ = try await repository.createEmptyDatabaseIfNeeded(username: "app-user", password: "app-secret")
-        let artifact = Data("compiled".utf8)
         let skillFiles = ["skills/weather/SKILL.md": "# Weather"]
-        let files: [String: Data] = [
-            "plugin.json": Data(#"{"name":"weather-tool"}"#.utf8),
-            "app.derrick/runtime.json": Data(#"{"language":"swift"}"#.utf8),
-            "app.derrick/plugin.py": Data("print(\"[]\")".utf8),
-            "app.derrick/plugin": artifact,
-            "skills/weather/SKILL.md": Data("# Weather".utf8),
-        ]
-        let release = PluginFactoryRelease(
+        let release = makeGoFactoryRelease(
             pluginID: "weather-tool",
-            version: "1.0.0",
-            manifestJSON: String(decoding: files["plugin.json"] ?? Data(), as: UTF8.self),
-            runtimeJSON: String(decoding: files["app.derrick/runtime.json"] ?? Data(), as: UTF8.self),
-            guestSource: "print(\"[]\")",
-            compiledArtifact: artifact,
-            skillFiles: skillFiles,
-            contentHash: PluginContentHash.hash(files: files),
-            reviewSummary: "approved"
+            manifestName: "weather-tool",
+            skillFiles: skillFiles
         )
 
         try await repository.savePluginFactoryRelease(release)
@@ -164,25 +136,11 @@ final class DBRepositoryTests: XCTestCase {
             )
         )
         _ = try await repository.createEmptyDatabaseIfNeeded(username: "app-user", password: "app-secret")
-        let artifact = Data("compiled".utf8)
         let skillFiles = ["skills/weather/SKILL.md": "# Weather"]
-        let files: [String: Data] = [
-            "plugin.json": Data(#"{"name":"weather-tool"}"#.utf8),
-            "app.derrick/runtime.json": Data(#"{"language":"swift"}"#.utf8),
-            "app.derrick/plugin.py": Data("print(\"[]\")".utf8),
-            "app.derrick/plugin": artifact,
-            "skills/weather/SKILL.md": Data("# Weather".utf8),
-        ]
-        let release = PluginFactoryRelease(
+        let release = makeGoFactoryRelease(
             pluginID: "weather-tool",
-            version: "1.0.0",
-            manifestJSON: String(decoding: files["plugin.json"] ?? Data(), as: UTF8.self),
-            runtimeJSON: String(decoding: files["app.derrick/runtime.json"] ?? Data(), as: UTF8.self),
-            guestSource: "print(\"[]\")",
-            compiledArtifact: artifact,
-            skillFiles: skillFiles,
-            contentHash: PluginContentHash.hash(files: files),
-            reviewSummary: "approved"
+            manifestName: "weather-tool",
+            skillFiles: skillFiles
         )
         try await repository.savePluginFactoryRelease(release)
 
@@ -633,4 +591,38 @@ final class DBRepositoryTests: XCTestCase {
         }
         return String(cString: c)
     }
+
+    /// Hash must match `packageFiles()`, which uses `guestSource` at the Go guest path.
+    private func makeGoFactoryRelease(
+        pluginID: String,
+        manifestName: String,
+        skillFiles: [String: String] = [:]
+    ) -> PluginFactoryRelease {
+        let artifact = Data("compiled".utf8)
+        let guestSource = "package main"
+        let manifestJSON = "{\"name\":\"\(manifestName)\"}"
+        let runtimeJSON = #"{"language":"go"}"#
+        var files: [String: Data] = [
+            "plugin.json": Data(manifestJSON.utf8),
+            "app.derrick/runtime.json": Data(runtimeJSON.utf8),
+            "app.derrick/plugin.go": Data(guestSource.utf8),
+            "app.derrick/plugin": artifact,
+        ]
+        for (path, body) in skillFiles {
+            files[path] = Data(body.utf8)
+        }
+        let release = PluginFactoryRelease(
+            pluginID: pluginID,
+            version: "1.0.0",
+            manifestJSON: manifestJSON,
+            runtimeJSON: runtimeJSON,
+            guestSource: guestSource,
+            compiledArtifact: artifact,
+            skillFiles: skillFiles,
+            contentHash: PluginContentHash.hash(files: files),
+            reviewSummary: "approved"
+        )
+        XCTAssertTrue(release.verifyIntegrity(), "test fixture hash must match packageFiles()")
+        return release
+    }
 }
diff --git a/packages/DerrickBackend/Sources/DerrickBackend/DaemonRuntime.swift b/packages/DerrickBackend/Sources/DerrickBackend/DaemonRuntime.swift
index 22131acd..96c27f92 100644
--- a/packages/DerrickBackend/Sources/DerrickBackend/DaemonRuntime.swift
+++ b/packages/DerrickBackend/Sources/DerrickBackend/DaemonRuntime.swift
@@ -52,7 +52,7 @@ public actor DaemonRuntime {
             service: .daemon,
             status: ok ? .ok : .degraded,
             detail: ok ? nil : "not bootstrapped",
-            guestRuntimeImage: DerrickGuestRuntime.pythonGuestDockerImage,
+            guestRuntimeImage: DerrickGuestRuntime.guestDockerImage,
             executableFingerprint: DaemonSelfRetirement.launchedFingerprint
         )
     }
diff --git a/packages/DerrickBackend/Sources/DerrickBackend/HITLApprovalNotifier.swift b/packages/DerrickBackend/Sources/DerrickBackend/HITLApprovalNotifier.swift
index e617f6a0..a74708e3 100644
--- a/packages/DerrickBackend/Sources/DerrickBackend/HITLApprovalNotifier.swift
+++ b/packages/DerrickBackend/Sources/DerrickBackend/HITLApprovalNotifier.swift
@@ -31,11 +31,15 @@ public enum HITLApprovalNotifier: Sendable {
 
         let isNetwork = isNetworkToolName(row.toolName)
         let host = host(fromNetworkToolName: row.toolName)
-        let title = isNetwork ? "Network access needed" : "Approval needed"
+        let blacklistPattern = blacklistPattern(from: row.argumentsJSON)
+        let title = isNetwork
+            ? (blacklistPattern == nil ? "Network access needed" : "Network blacklist")
+            : "Approval needed"
         let body: String
-        if isNetwork, let host {
-            let suffix = Self.registrableSuffix(for: host)
-            body = "Allow *.\(suffix)? Tap to approve or deny. Always Allow covers all subdomains."
+        if isNetwork, let blacklistPattern {
+            body = "This request matches blacklist \(blacklistPattern). Tap to allow this run, remove from blacklist, or deny."
+        } else if isNetwork, let host {
+            body = "Network access to \(host). Tap to approve or deny."
         } else {
             let preview = truncated(row.argumentsJSON, limit: 160)
             body = preview.isEmpty
@@ -80,12 +84,13 @@ public enum HITLApprovalNotifier: Sendable {
         return host.isEmpty ? nil : host
     }
 
-    /// Last two labels — same rule as egress permanent allow (`*.apple.com` ← `securemetrics.apple.com`).
-    private static func registrableSuffix(for host: String) -> String {
-        let normalized = host.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
-        let parts = normalized.split(separator: ".").map(String.init)
-        guard parts.count >= 2 else { return normalized }
-        return parts.suffix(2).joined(separator: ".")
+    private static func blacklistPattern(from argumentsJSON: String) -> String? {
+        guard let data = argumentsJSON.data(using: .utf8),
+              let object = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
+              object["kind"] as? String == "blacklist" else {
+            return nil
+        }
+        return object["pattern"] as? String
     }
 
     private static func truncated(_ text: String, limit: Int) -> String {
diff --git a/packages/DerrickBackend/Sources/DerrickBackend/PluginFactoryCreateWorkflow.swift b/packages/DerrickBackend/Sources/DerrickBackend/PluginFactoryCreateWorkflow.swift
index ce7af8ef..34a8199e 100644
--- a/packages/DerrickBackend/Sources/DerrickBackend/PluginFactoryCreateWorkflow.swift
+++ b/packages/DerrickBackend/Sources/DerrickBackend/PluginFactoryCreateWorkflow.swift
@@ -36,56 +36,70 @@ enum PluginFactoryCreateWorkflow {
         ) async throws -> MCPToolCallResultDTO
     ) async throws {
         let input = try PluginFactoryCreateInput.decodeJSON(request.inputJSON)
-        guard input.pluginType == .connector else {
+        guard input.pluginType == .connector || input.pluginType == .custom else {
             try await fail(
                 workflowID: workflowID,
                 stage: "type",
-                message: "Only connector plugins can be built in the factory. News lists are created from the News reader wizard.",
+                message: "This plugin type cannot be built in the factory.",
                 repositoryProvider: repositoryProvider
             )
             return
         }
-        guard let vendor = input.vendor else {
+        guard let pluginID = input.pluginID, !pluginID.isEmpty else {
             try await fail(
                 workflowID: workflowID,
-                stage: "vendor",
-                message: "Choose a messaging vendor for this connector.",
+                stage: "name",
+                message: "Name this plugin before creating it.",
                 repositoryProvider: repositoryProvider
             )
             return
         }
-        guard let pluginID = input.pluginID, !pluginID.isEmpty else {
+        guard !input.description.isEmpty else {
             try await fail(
                 workflowID: workflowID,
-                stage: "name",
-                message: "Name this connector before creating it.",
+                stage: "description",
+                message: "Describe what the plugin should do, then try again.",
                 repositoryProvider: repositoryProvider
             )
             return
         }
-        guard let auth = input.auth else {
+
+        if input.pluginType == .custom {
+            try await runCustomBuild(
+                workflowID: workflowID,
+                request: request,
+                input: input,
+                pluginID: pluginID,
+                baseContext: baseContext,
+                repositoryProvider: repositoryProvider,
+                executeTool: executeTool
+            )
+            return
+        }
+
+        guard let vendor = input.vendor else {
             try await fail(
                 workflowID: workflowID,
-                stage: "auth",
-                message: "Save the connector credentials before creating it.",
+                stage: "vendor",
+                message: "Could not determine which messaging service this plugin targets.",
                 repositoryProvider: repositoryProvider
             )
             return
         }
-        guard auth.authScheme.isSupportedInWizard else {
+        guard let auth = input.auth else {
             try await fail(
                 workflowID: workflowID,
                 stage: "auth",
-                message: "OAuth connectors are not available yet. Use a bot token or API key.",
+                message: "Save the plugin credentials before creating it.",
                 repositoryProvider: repositoryProvider
             )
             return
         }
-        guard !input.description.isEmpty else {
+        guard auth.authScheme.isSupportedInWizard else {
             try await fail(
                 workflowID: workflowID,
-                stage: "description",
-                message: "Choose a vendor and create the connector again.",
+                stage: "auth",
+                message: "OAuth connectors are not available yet. Use a bot token or API key.",
                 repositoryProvider: repositoryProvider
             )
             return
@@ -194,6 +208,87 @@ enum PluginFactoryCreateWorkflow {
         )
     }
 
+    private static func runCustomBuild(
+        workflowID: String,
+        request: WorkflowStartRequest,
+        input: PluginFactoryCreateInput,
+        pluginID: String,
+        baseContext: ExecutionContextWire,
+        repositoryProvider: @escaping @Sendable () async throws -> DBRepository,
+        executeTool: @escaping (
+            String,
+            String,
+            ExecutionContextWire,
+            ServicePrincipal,
+            String?,
+            String?,
+            String,
+            String
+        ) async throws -> MCPToolCallResultDTO
+    ) async throws {
+        try await log(
+            workflowID: workflowID,
+            stage: "factory",
+            message: "Writing SKILL.md, building the guest program, and running trial tests…",
+            repositoryProvider: repositoryProvider
+        )
+        let goal = input.customBuildGoal()
+        let buildArgs = try buildArguments(goal: goal, hostManifest: nil)
+        let buildResult = try await executeTool(
+            AllowedMCPTool.pluginFactoryBuild.rawValue,
+            buildArgs,
+            baseContext,
+            request.principal,
+            request.helperAPIKey,
+            request.helperReviewerModelJSON,
+            workflowID,
+            "factory"
+        )
+        if buildResult.isError {
+            try await fail(
+                workflowID: workflowID,
+                stage: "factory",
+                message: userFacingToolError(buildResult, fallback: "Plugin factory could not finish building the plugin."),
+                repositoryProvider: repositoryProvider
+            )
+            return
+        }
+
+        guard let summary = decodeBuildResult(buildResult.text),
+              summary.ok != false,
+              let savedID = summary.pluginID?.trimmingCharacters(in: .whitespacesAndNewlines),
+              !savedID.isEmpty
+        else {
+            let decoded = decodeBuildResult(buildResult.text)
+            let raw = decoded?.error
+                ?? decoded?.reviewSummary
+                ?? "Plugin factory did not return a saved plugin."
+            try await fail(
+                workflowID: workflowID,
+                stage: "factory",
+                message: PluginFactoryCreateFailureMessage.userFacing(raw),
+                repositoryProvider: repositoryProvider
+            )
+            return
+        }
+
+        let resultJSON = try JSONEncoder.service.encode(
+            PluginFactoryCreateResult(
+                pluginID: savedID,
+                version: summary.version ?? "1.0.0",
+                vendor: "custom",
+                reviewSummary: summary.reviewSummary ?? ""
+            )
+        )
+        let resultText = String(decoding: resultJSON, as: UTF8.self)
+        try await complete(
+            workflowID: workflowID,
+            message: "Plugin saved as /\(savedID).",
+            resultJSON: resultText,
+            repositoryProvider: repositoryProvider
+        )
+    }
+
     private static func crawlArguments(
         startURL: String,
         vendor: PluginFactoryCreateInput.ConnectorVendor,
diff --git a/packages/DerrickBackend/Tests/DerrickBackendTests/PluginMessagingIngressAdapterTests.swift b/packages/DerrickBackend/Tests/DerrickBackendTests/PluginMessagingIngressAdapterTests.swift
index c2c11edc..717f1f0b 100644
--- a/packages/DerrickBackend/Tests/DerrickBackendTests/PluginMessagingIngressAdapterTests.swift
+++ b/packages/DerrickBackend/Tests/DerrickBackendTests/PluginMessagingIngressAdapterTests.swift
@@ -542,10 +542,10 @@ import Testing
         _ = try await repository.createEmptyDatabaseIfNeeded(username: "app-user", password: "app-secret")
         let manifestJSON = """
         {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connection","version":"1.0.0",\
-        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","messaging_ops":["send_message"]}}}
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","messaging_ops":["send_message"]}}}
         """
         let guestSource = "import json, sys\njson.dump([], sys.stdout)"
-        let runtimeJSON = #"{"language":"python","entrypoint":"./app.derrick/plugin.py"}"#
+        let runtimeJSON = #"{"language":"go","entrypoint":"./app.derrick/plugin.go"}"#
         let draft = PluginFactoryRelease(
             pluginID: "slack-connection",
             version: "1.0.0",
diff --git a/packages/DockerRunnerXPC/Sources/DockerRunnerXPC/DockerRunRequestValidator.swift b/packages/DockerRunnerXPC/Sources/DockerRunnerXPC/DockerRunRequestValidator.swift
index 478c0adc..ec7cd578 100644
--- a/packages/DockerRunnerXPC/Sources/DockerRunnerXPC/DockerRunRequestValidator.swift
+++ b/packages/DockerRunnerXPC/Sources/DockerRunnerXPC/DockerRunRequestValidator.swift
@@ -93,11 +93,9 @@ public enum DockerRunRequestValidator: Sendable {
             return .disallowedDockerSubcommand(subcommand)
         }
 
-        if subcommand == "image" {
-            guard let second = dockerArgs.dropFirst().first,
-                  DockerHostLaunch.allowedImageSubcommands.contains(second) else {
-                return .disallowedDockerSubcommand("image \(dockerArgs.dropFirst().first ?? "<missing>")")
-            }
+        if subcommand == "image",
+           let error = validateImageArguments(dockerArgs) {
+            return error
         }
         if subcommand == "exec",
            let error = validateExecArguments(dockerArgs) {
@@ -206,20 +204,17 @@ public enum DockerRunRequestValidator: Sendable {
         case "sh":
             guard args.count == 3,
                   args[1] == "-c",
-                  args[2] == "cat > /tmp/guest.py"
+                  args[2] == "cat > /tmp/guest && chmod +x /tmp/guest"
+                      || args[2] == DockerWorkerRuntime.guestWriteSourceShell
+                      || args[2] == DockerWorkerRuntime.guestCompileShell
+                      || args[2] == DockerWorkerRuntime.guestReadBinaryShell
             else {
                 return .disallowedDockerFlag("exec \(command)")
             }
-        case "python3":
-            guard args.count == 2, args[1] == "/tmp/guest.py" else {
-                return .disallowedDockerFlag("exec \(command)")
-            }
-        case "/usr/local/bin/derrick-web-crawler":
-            guard args == ["/usr/local/bin/derrick-web-crawler"] else {
-                return .disallowedDockerFlag("exec \(command)")
-            }
-        case "/usr/local/bin/derrick-file-extractor":
-            guard args == ["/usr/local/bin/derrick-file-extractor"] else {
+        case DockerWorkerRuntime.crawlerBinary,
+             DockerWorkerRuntime.extractorBinary,
+             DockerWorkerRuntime.guestBinaryPath:
+            guard args == [command] else {
                 return .disallowedDockerFlag("exec \(command)")
             }
         default:
@@ -244,12 +239,45 @@ public enum DockerRunRequestValidator: Sendable {
         guard args.count == 5 else {
             return .disallowedDockerFlag("build extra arguments")
         }
-        guard DockerProductImagePolicy.isAllowedWebCrawlerBuild(
+        if DockerProductImagePolicy.isAllowedWorkerBuild(
+            dockerfilePath: dockerfile,
+            imageTag: tag,
+            contextPath: context
+        ) {
+            return nil
+        }
+        if DockerProductImagePolicy.isAllowedWebCrawlerBuild(
             dockerfilePath: dockerfile,
             imageTag: tag,
             contextPath: context
-        ) else {
-            return .disallowedDockerFlag("build product image")
+        ) {
+            return nil
+        }
+        return .disallowedDockerFlag("build product image")
+    }
+
+    private static func validateImageArguments(
+        _ dockerArgs: [String]
+    ) -> DockerRunRequestValidationError? {
+        let args = Array(dockerArgs.dropFirst())
+        guard let second = args.first,
+              DockerHostLaunch.allowedImageSubcommands.contains(second) else {
+            return .disallowedDockerSubcommand("image \(args.first ?? "<missing>")")
+        }
+        guard second == "inspect" else { return nil }
+        if args.count == 2 {
+            return nil
+        }
+        guard args.count == 4,
+              args[1] == "--format",
+              args[2] == "{{.Id}}" else {
+            return .disallowedDockerFlag("image inspect")
+        }
+        let tag = args[3]
+        guard tag == DockerWorkerRuntime.image
+            || tag == DockerProductImagePolicy.webCrawlerImage
+            || tag == DerrickGuestRuntime.guestDockerImage else {
+            return .disallowedDockerFlag("image inspect tag")
         }
         return nil
     }
diff --git a/packages/DockerRunnerXPC/Tests/DockerRunnerXPCTests/DockerRunnerXPCTests.swift b/packages/DockerRunnerXPC/Tests/DockerRunnerXPCTests/DockerRunnerXPCTests.swift
index e806f4ad..bd387784 100644
--- a/packages/DockerRunnerXPC/Tests/DockerRunnerXPCTests/DockerRunnerXPCTests.swift
+++ b/packages/DockerRunnerXPC/Tests/DockerRunnerXPCTests/DockerRunnerXPCTests.swift
@@ -211,8 +211,11 @@ struct DockerRunnerXPCTests {
             ["version"],
             ["image", "inspect", "img"],
             ["pull", "img"],
-            ["exec", "-i", "c", "python3", "/tmp/guest.py"],
-            ["exec", "-i", "c", "sh", "-c", "cat > /tmp/guest.py"],
+            ["exec", "-i", "c", DockerWorkerRuntime.guestBinaryPath],
+            ["exec", "-i", "c", "sh", "-c", "cat > /tmp/guest && chmod +x /tmp/guest"],
+            ["exec", "-i", "c", "sh", "-c", DockerWorkerRuntime.guestWriteSourceShell],
+            ["exec", "c", "sh", "-c", DockerWorkerRuntime.guestCompileShell],
+            ["exec", "c", "sh", "-c", DockerWorkerRuntime.guestReadBinaryShell],
             ["exec", "-i", "c", "/usr/local/bin/derrick-web-crawler"],
             ["create", "--label", "app.derrick=runtime", "--entrypoint", "/bin/sleep", "--name", "c", "derrick-web-crawler:swift-6.4-v1", "infinity"],
             [
@@ -229,7 +232,7 @@ struct DockerRunnerXPCTests {
                 "--memory", "1g",
                 "--security-opt", "no-new-privileges",
                 "--cap-drop", "ALL",
-                "python:3.14.7",
+                DockerWorkerRuntime.image,
                 "/bin/sleep",
                 "infinity",
             ],
@@ -256,13 +259,13 @@ struct DockerRunnerXPCTests {
         }
     }
 
-    @Test func rejectsInvalidPythonGuestExecCommands() {
+    @Test func rejectsInvalidGoGuestExecCommands() {
         for args in [
-            ["exec", "-i", "c", "python3", "/tmp/other.py"],
-            ["exec", "-i", "c", "python3", "/tmp/guest.py", "extra"],
-            ["exec", "-i", "c", "sh", "-c", "cat > /tmp/other.py"],
+            ["exec", "-i", "c", "python3", "/tmp/guest.go"],
+            ["exec", "-i", "c", DockerWorkerRuntime.guestBinaryPath, "extra"],
+            ["exec", "-i", "c", "sh", "-c", "cat > /tmp/other"],
             ["exec", "-i", "c", "sh", "-c", "rm -rf /"],
-            ["exec", "-i", "c", "sh", "-c", "cat > /tmp/guest.py", "extra"],
+            ["exec", "-i", "c", "sh", "-c", "go build /tmp/plugin.go"],
             ["exec", "-i", "c", "swift", "/tmp/plugin.swift"],
             ["exec", "-i", "c", "/tmp/plugin"],
             ["exec", "-i", "c", "swiftc", "-O", "/tmp/plugin.swift", "-o", "/tmp/plugin"],
@@ -354,7 +357,7 @@ struct DockerRunnerXPCTests {
 
     @Test func rejectsCreateWithoutRuntimeLabel() {
         let r = request(arguments: DockerHostLaunch.dockerCLIArguments([
-            "create", "--name", "c", "python:3.14.7", "/bin/sleep", "infinity",
+            "create", "--name", "c", DockerWorkerRuntime.image, "/bin/sleep", "infinity",
         ]))
         #expect(DockerRunRequestValidator.validate(r) == .disallowedDockerFlag("create missing runtime label"))
     }
diff --git a/packages/MCPServer/Sources/FactoryHarness/FactoryHarnessMain.swift b/packages/MCPServer/Sources/FactoryHarness/FactoryHarnessMain.swift
index 0359bf12..dfe1be76 100644
--- a/packages/MCPServer/Sources/FactoryHarness/FactoryHarnessMain.swift
+++ b/packages/MCPServer/Sources/FactoryHarness/FactoryHarnessMain.swift
@@ -26,7 +26,7 @@ enum FactoryHarnessMain {
         let goal = input.connectorBuildGoal(crawlSummary: SlackConnectorFactoryInput.defaultCrawlSummary)
 
         fputs("FactoryHarness: building slack full-sync connector…\n", stderr)
-        let executor = PythonPluginFactoryDockerExecutor(executor: DirectShellDocker.executor())
+        let executor = GoPluginFactoryDockerExecutor(executor: DirectShellDocker.executor())
         let release = try await PluginFactorySession(
             configuration: PluginFactoryConfiguration(maxBuilderAttempts: 3)
         ).build(
diff --git a/packages/MCPServer/Sources/FactoryHarnessSupport/LiveFactoryModels.swift b/packages/MCPServer/Sources/FactoryHarnessSupport/LiveFactoryModels.swift
index 889e2aac..e721d2c3 100644
--- a/packages/MCPServer/Sources/FactoryHarnessSupport/LiveFactoryModels.swift
+++ b/packages/MCPServer/Sources/FactoryHarnessSupport/LiveFactoryModels.swift
@@ -34,7 +34,7 @@ public actor LiveFactoryBuilder: PluginFactoryBuilder {
                 """
                 The host already assigned plugin_id \(host.pluginID) and these secret ids: \
                 \(host.secrets.map(\.id).joined(separator: ", ")). \
-                Return python_source and test_input_json. Do not pick a different plugin_id or secret ids.
+                Return go_source and test_input_json. Do not pick a different plugin_id or secret ids.
                 """
             )
         }
@@ -75,41 +75,8 @@ public actor LiveFactoryBuilder: PluginFactoryBuilder {
     private static func builderSystemPrompt(for userGoal: String) -> String {
         """
         You are the Derrick plugin builder. Convert the user's goal into one complete Agent Plugin draft.
-        Return exactly one JSON object with these keys:
-        plugin_id (string), version (string), description (string), python_source (string),
-        test_input_json (string containing valid JSON — a serialized object, not prose),
-        skill_files (array of objects with path and body),
-        secrets (array of objects with id, label, and kind; required for connector plugins),
-        role (string, optional: "connector" or "standard"),
-        messaging_ops (array of strings, required for connector role).
-        plugin_id must use lowercase letters, numbers, hyphens, and dots only
-        (for example my-connector). Never use underscores in plugin_id.
-        If the plugin needs a username, password, token, or API key, declare them in secrets.
-        kind must be username, password, token, or api_key. id is a stable Keychain key
-        such as username or bot_token. label is the text shown when the user saves the value.
-        Never put real credentials in python_source.
-        Set role to "connector" when the plugin sends and receives messages with an external
-        messaging service (any chat or mail connector). Omit role or use "standard" otherwise.
-        For role connector, include messaging_ops: an array of implemented ops
-        (send_message, poll_inbox, sync_threads). It must match the user goal scope and test_input_json.
-        Do not return manifest_json. The host creates the canonical Agent Plugin manifest.
-        If skill_files is not needed, return an empty array. Every skill file path must be exactly
-        skills/<name>/SKILL.md. Never use manifest.json or other paths in skill_files.
-        \(DerrickGuestPython.modelContract)
+        \(ScriptExecContractPrompts.pluginFactoryBuilderGuide())
         \(ConnectorContractPrompts.builderGuide(forUserGoal: userGoal))
-        Before returning the draft, self-check the implementation:
-        - Sort every returned collection by an explicit stable key after parsing and de-duplicate it.
-        - Match host responses by the emitted request_id.
-        - Use only the Python standard library (no pip, requests, urllib, socket, or subprocess).
-        - The direct test input must exercise the terminal result path with matching http_results fixtures.
-        For messaging connector plugins (role connector) that call a vendor HTTP API:
-        - Declare secrets in the manifest only. Never hard-code credentials.
-        - Parse each http_results body as JSON when the vendor returns JSON.
-        - When scope includes send_message, the final result.emit must include sent_message.
-        - Direct tests for poll_inbox must include a non-empty messages array; runtime empty messages with vendor success is success.
-        - When scope includes sync_threads, the final result.emit must include a non-empty threads array.
-          Each thread needs vendor_thread_id (opaque vendor ID) and title (human label for the host channel picker).
-          Emit only conversations the saved secret can access; for Slack skip channels where is_member is false.
         When vendor documentation is supplied in the user prompt, use it only to fill may_call HTTP details.
         """
     }
@@ -120,7 +87,7 @@ public actor LiveFactoryBuilder: PluginFactoryBuilder {
             "plugin_id": AgentSchema(type: .string),
             "version": AgentSchema(type: .string),
             "description": AgentSchema(type: .string),
-            "python_source": AgentSchema(type: .string),
+            "go_source": AgentSchema(type: .string),
             "test_input_json": AgentSchema(type: .string),
             "skill_files": AgentSchema(
                 type: .array,
@@ -149,7 +116,7 @@ public actor LiveFactoryBuilder: PluginFactoryBuilder {
             "messaging_ops": AgentSchema(type: .array, items: AgentSchema(type: .string)),
         ],
         required: [
-            "plugin_id", "version", "description", "python_source",
+            "plugin_id", "version", "description", "go_source",
             "test_input_json", "skill_files",
         ]
     )
@@ -181,7 +148,7 @@ public actor LiveFactoryReviewer: PluginFactoryReviewer {
                 test_input_json:
                 \(String(decoding: draft.testInput, as: UTF8.self))
 
-                Python source:
+                Go source:
                 \(draft.guestSource)
 
                 Direct test output:
@@ -199,12 +166,8 @@ public actor LiveFactoryReviewer: PluginFactoryReviewer {
 
     private static func reviewerSystemPrompt(for userGoal: String?) -> String {
         """
-    You are Derrick's independent plugin alignment and safety reviewer.
-    Return exactly one JSON object:
-    {"decision":"approved|rejected","summary":"...","findings":[
-      {"severity":"info|warning|blocking","category":"alignment|safety|correctness|privacy|supplyChain","message":"..."}
-    ]}
-    Reject unsafe or non-deterministic code. Approve when direct test output matches fixtures through result.emit.
+    Review the user's goal, manifest, test_input_json, exact Go source, and direct test output.
+    \(ScriptExecContractPrompts.pluginFactoryReviewerGuide())
     \(ConnectorContractPrompts.reviewerGuide(forUserGoal: userGoal))
     """
     }
diff --git a/packages/MCPServer/Sources/FactoryHarnessSupport/ReferenceSlackConnectorDraft.swift b/packages/MCPServer/Sources/FactoryHarnessSupport/ReferenceSlackConnectorDraft.swift
index 8e102534..54110bc1 100644
--- a/packages/MCPServer/Sources/FactoryHarnessSupport/ReferenceSlackConnectorDraft.swift
+++ b/packages/MCPServer/Sources/FactoryHarnessSupport/ReferenceSlackConnectorDraft.swift
@@ -41,7 +41,7 @@ public enum ReferenceSlackConnectorDraft {
         let manifestJSON = """
         {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connection","version":"1.0.0",\
         "description":"Slack messaging connector",\
-        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","auth_scheme":"bot_token","secrets":[{"id":"bot_token","label":"Bot Token","kind":"token"}],"permissions":["channels:history","channels:read","chat:write","groups:history","groups:read","im:history","im:read","mpim:history","mpim:read","users:read"],"messaging_ops":[\(opsJSON)]}}}
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","auth_scheme":"bot_token","secrets":[{"id":"bot_token","label":"Bot Token","kind":"token"}],"permissions":["channels:history","channels:read","chat:write","groups:history","groups:read","im:history","im:read","mpim:history","mpim:read","users:read"],"messaging_ops":[\(opsJSON)]}}}
         """
         return PluginFactoryDraft(
             manifestJSON: manifestJSON,
@@ -52,104 +52,278 @@ public enum ReferenceSlackConnectorDraft {
     }
 
     private static let fullSyncSource = """
-    import json, sys
-    def emit(x): json.dump(x, sys.stdout, separators=(",", ":"))
-    def sorted_results(results):
-        seen = set()
-        out = []
-        for item in sorted(results or [], key=lambda r: str(r.get("request_id",""))):
-            rid = str(item.get("request_id",""))
-            if rid and rid not in seen:
-                seen.add(rid)
-                out.append(item)
+    package main
+
+    import (
+        "encoding/json"
+        "os"
+        "sort"
+    )
+
+    func emit(v any) {
+        enc := json.NewEncoder(os.Stdout)
+        enc.SetEscapeHTML(false)
+        _ = enc.Encode(v)
+    }
+
+    func sortedResults(results []map[string]any) []map[string]any {
+        if len(results) == 0 {
+            return nil
+        }
+        sort.Slice(results, func(i, j int) bool {
+            left, _ := results[i]["request_id"].(string)
+            right, _ := results[j]["request_id"].(string)
+            return left < right
+        })
+        seen := map[string]bool{}
+        out := []map[string]any{}
+        for _, item := range results {
+            rid, _ := item["request_id"].(string)
+            if rid == "" || seen[rid] {
+                continue
+            }
+            seen[rid] = true
+            out = append(out, item)
+        }
         return out
-    def message_from(msg, default_channel):
-        if not isinstance(msg, dict): return None
-        channel = msg.get("channel") or default_channel
-        ts = msg.get("ts")
-        if not channel or not ts: return None
-        thread_ts = msg.get("thread_ts")
-        parent = None
-        if thread_ts and str(thread_ts) != str(ts):
-            parent = str(thread_ts)
-        reply_count = int(msg.get("reply_count") or 0)
-        row = {"vendor_thread_id":channel,"vendor_message_id":str(ts),"direction":"inbound","sender":msg.get("user") or "slack","body":msg.get("text") or "","created_at":str(ts),"reply_count":reply_count}
-        if parent:
+    }
+
+    func asMap(v any) map[string]any {
+        if m, ok := v.(map[string]any); ok {
+            return m
+        }
+        return map[string]any{}
+    }
+
+    func asString(v any) string {
+        if s, ok := v.(string); ok {
+            return s
+        }
+        return ""
+    }
+
+    func messageFrom(msg map[string]any, defaultChannel string) map[string]any {
+        channel := asString(msg["channel"])
+        if channel == "" {
+            channel = defaultChannel
+        }
+        ts := asString(msg["ts"])
+        if channel == "" || ts == "" {
+            return nil
+        }
+        threadTS := asString(msg["thread_ts"])
+        parent := ""
+        if threadTS != "" && threadTS != ts {
+            parent = threadTS
+        }
+        replyCount := 0
+        if n, ok := msg["reply_count"].(float64); ok {
+            replyCount = int(n)
+        }
+        row := map[string]any{
+            "vendor_thread_id": channel,
+            "vendor_message_id": ts,
+            "direction": "inbound",
+            "sender": func() string {
+                if s := asString(msg["user"]); s != "" {
+                    return s
+                }
+                return "slack"
+            }(),
+            "body": asString(msg["text"]),
+            "created_at": ts,
+            "reply_count": replyCount,
+        }
+        if parent != "" {
             row["parent_vendor_message_id"] = parent
+        }
         return row
-    def main():
-        event = json.load(sys.stdin)
-        params = event.get("params") or {}
-        op = params.get("messaging_op")
-        if event.get("kind") == "manual" and op == "sync_threads":
-            emit([{"verb":"http.request","request_id":"sync-1","method":"GET","url":"https://slack.com/api/conversations.list?types=public_channel,private_channel&limit=200&exclude_archived=true","headers":{"Authorization":"Bearer {{secret:bot_token}}"}}])
+    }
+
+    func main() {
+        var event map[string]any
+        if err := json.NewDecoder(os.Stdin).Decode(&event); err != nil {
             return
-        if event.get("kind") == "manual" and op == "poll_inbox":
-            channel = params.get("vendor_thread_id") or params.get("channel")
-            parent = params.get("parent_vendor_message_id") or params.get("thread_ts")
-            if not channel:
-                emit([{"verb":"result.emit","messages":[]}])
+        }
+        params := asMap(event["params"])
+        op := asString(params["messaging_op"])
+        kind := asString(event["kind"])
+
+        switch {
+        case kind == "manual" && op == "sync_threads":
+            emit([]map[string]any{{
+                "verb": "http.request", "request_id": "sync-1", "method": "GET",
+                "url": "https://slack.com/api/conversations.list?types=public_channel,private_channel&limit=200&exclude_archived=true",
+                "headers": map[string]any{"Authorization": "Bearer {{secret:bot_token}}"},
+            }})
+            return
+        case kind == "manual" && op == "poll_inbox":
+            channel := asString(params["vendor_thread_id"])
+            if channel == "" {
+                channel = asString(params["channel"])
+            }
+            parent := asString(params["parent_vendor_message_id"])
+            if parent == "" {
+                parent = asString(params["thread_ts"])
+            }
+            if channel == "" {
+                emit([]map[string]any{{"verb": "result.emit", "messages": []map[string]any{}}})
                 return
-            if parent:
-                url = "https://slack.com/api/conversations.replies?channel=" + str(channel) + "&ts=" + str(parent) + "&limit=50"
-                emit([{"verb":"http.request","request_id":"replies-1","method":"GET","url":url,"headers":{"Authorization":"Bearer {{secret:bot_token}}"}}])
+            }
+            if parent != "" {
+                url := "https://slack.com/api/conversations.replies?channel=" + channel + "&ts=" + parent + "&limit=50"
+                emit([]map[string]any{{
+                    "verb": "http.request", "request_id": "replies-1", "method": "GET", "url": url,
+                    "headers": map[string]any{"Authorization": "Bearer {{secret:bot_token}}"},
+                }})
                 return
-            url = "https://slack.com/api/conversations.history?channel=" + str(channel) + "&limit=50"
-            emit([{"verb":"http.request","request_id":"poll-1","method":"GET","url":url,"headers":{"Authorization":"Bearer {{secret:bot_token}}"}}])
+            }
+            url := "https://slack.com/api/conversations.history?channel=" + channel + "&limit=50"
+            emit([]map[string]any{{
+                "verb": "http.request", "request_id": "poll-1", "method": "GET", "url": url,
+                "headers": map[string]any{"Authorization": "Bearer {{secret:bot_token}}"},
+            }})
             return
-        if event.get("kind") == "message_in_room" and op == "send_message":
-            channel = params.get("vendor_thread_id")
-            text = params.get("text", "")
-            parent = params.get("parent_vendor_message_id") or params.get("thread_ts")
-            payload = {"channel":channel,"text":text}
-            if parent:
+        case kind == "message_in_room" && op == "send_message":
+            channel := asString(params["vendor_thread_id"])
+            text := asString(params["text"])
+            parent := asString(params["parent_vendor_message_id"])
+            if parent == "" {
+                parent = asString(params["thread_ts"])
+            }
+            payload := map[string]any{"channel": channel, "text": text}
+            if parent != "" {
                 payload["thread_ts"] = parent
-            emit([{"verb":"http.request","request_id":"send-1","method":"POST","url":"https://slack.com/api/chat.postMessage","headers":{"Authorization":"Bearer {{secret:bot_token}}","Content-Type":"application/json"},"json":payload}])
+            }
+            emit([]map[string]any{{
+                "verb": "http.request", "request_id": "send-1", "method": "POST",
+                "url": "https://slack.com/api/chat.postMessage",
+                "headers": map[string]any{
+                    "Authorization": "Bearer {{secret:bot_token}}",
+                    "Content-Type": "application/json",
+                },
+                "json": payload,
+            }})
             return
-        if event.get("kind") == "http_results" and op == "sync_threads":
-            threads = []
-            for item in sorted_results(event.get("http_results")):
-                if item.get("request_id") != "sync-1": continue
-                payload = json.loads(item.get("body") or "{}")
-                if payload.get("ok") is False:
-                    emit([{"verb":"result.emit","title":"Slack list failed","summary":str(payload.get("error") or "unknown")}])
+        case kind == "http_results" && op == "sync_threads":
+            threads := []map[string]any{}
+            rawResults, _ := event["http_results"].([]any)
+            results := []map[string]any{}
+            for _, item := range rawResults {
+                results = append(results, asMap(item))
+            }
+            for _, item := range sortedResults(results) {
+                if asString(item["request_id"]) != "sync-1" {
+                    continue
+                }
+                var payload map[string]any
+                _ = json.Unmarshal([]byte(asString(item["body"])), &payload)
+                if payload["ok"] == false {
+                    emit([]map[string]any{{
+                        "verb": "result.emit",
+                        "title": "Slack list failed",
+                        "summary": asString(payload["error"]),
+                    }})
                     return
-                for ch in sorted(payload.get("channels") or [], key=lambda c: str(c.get("id",""))):
-                    if ch.get("is_member") is False:
+                }
+                channels, _ := payload["channels"].([]any)
+                sort.Slice(channels, func(i, j int) bool {
+                    left := asMap(channels[i])
+                    right := asMap(channels[j])
+                    return asString(left["id"]) < asString(right["id"])
+                })
+                for _, chAny := range channels {
+                    ch := asMap(chAny)
+                    if ch["is_member"] == false {
                         continue
-                    cid = ch.get("id")
-                    name = ch.get("name") or cid
-                    if cid:
-                        threads.append({"vendor_thread_id":cid,"title":"#" + str(name)})
-            emit([{"verb":"result.emit","threads":threads}])
+                    }
+                    cid := asString(ch["id"])
+                    name := asString(ch["name"])
+                    if name == "" {
+                        name = cid
+                    }
+                    if cid != "" {
+                        threads = append(threads, map[string]any{
+                            "vendor_thread_id": cid,
+                            "title": "#" + name,
+                        })
+                    }
+                }
+            }
+            emit([]map[string]any{{"verb": "result.emit", "threads": threads}})
             return
-        if event.get("kind") == "http_results" and op == "poll_inbox":
-            channel = params.get("vendor_thread_id") or params.get("channel")
-            messages = []
-            for item in sorted_results(event.get("http_results")):
-                if item.get("request_id") not in ("poll-1", "replies-1"): continue
-                payload = json.loads(item.get("body") or "{}")
-                if payload.get("ok") is False:
-                    emit([{"verb":"result.emit","title":"Slack blocked this thread","summary":str(payload.get("error") or "unknown")}])
+        case kind == "http_results" && op == "poll_inbox":
+            channel := asString(params["vendor_thread_id"])
+            if channel == "" {
+                channel = asString(params["channel"])
+            }
+            messages := []map[string]any{}
+            rawResults, _ := event["http_results"].([]any)
+            results := []map[string]any{}
+            for _, item := range rawResults {
+                results = append(results, asMap(item))
+            }
+            for _, item := range sortedResults(results) {
+                rid := asString(item["request_id"])
+                if rid != "poll-1" && rid != "replies-1" {
+                    continue
+                }
+                var payload map[string]any
+                _ = json.Unmarshal([]byte(asString(item["body"])), &payload)
+                if payload["ok"] == false {
+                    emit([]map[string]any{{
+                        "verb": "result.emit",
+                        "title": "Slack blocked this thread",
+                        "summary": asString(payload["error"]),
+                    }})
                     return
-                for msg in sorted(payload.get("messages") or [], key=lambda m: str(m.get("ts",""))):
-                    parsed = message_from(msg, channel)
-                    if parsed: messages.append(parsed)
-            emit([{"verb":"result.emit","messages":messages}])
+                }
+                rawMessages, _ := payload["messages"].([]any)
+                sort.Slice(rawMessages, func(i, j int) bool {
+                    left := asMap(rawMessages[i])
+                    right := asMap(rawMessages[j])
+                    return asString(left["ts"]) < asString(right["ts"])
+                })
+                for _, msgAny := range rawMessages {
+                    parsed := messageFrom(asMap(msgAny), channel)
+                    if parsed != nil {
+                        messages = append(messages, parsed)
+                    }
+                }
+            }
+            emit([]map[string]any{{"verb": "result.emit", "messages": messages}})
             return
-        if event.get("kind") == "http_results" and op == "send_message":
-            body = {}
-            for item in sorted_results(event.get("http_results")):
-                if item.get("request_id") == "send-1":
-                    body = json.loads(item.get("body") or "{}")
-            if body.get("ok"):
-                ts = body.get("ts") or (body.get("message") or {}).get("ts")
-                emit([{"verb":"result.emit","sent_message":{"vendor_message_id":ts,"created_at":ts}}])
-            else:
-                emit([{"verb":"result.emit","summary":"send failed"}])
+        case kind == "http_results" && op == "send_message":
+            body := map[string]any{}
+            rawResults, _ := event["http_results"].([]any)
+            results := []map[string]any{}
+            for _, item := range rawResults {
+                results = append(results, asMap(item))
+            }
+            for _, item := range sortedResults(results) {
+                if asString(item["request_id"]) == "send-1" {
+                    _ = json.Unmarshal([]byte(asString(item["body"])), &body)
+                }
+            }
+            if body["ok"] == true {
+                ts := asString(body["ts"])
+                if ts == "" {
+                    ts = asString(asMap(body["message"])["ts"])
+                }
+                emit([]map[string]any{{
+                    "verb": "result.emit",
+                    "sent_message": map[string]any{
+                        "vendor_message_id": ts,
+                        "created_at": ts,
+                    },
+                }})
+            } else {
+                emit([]map[string]any{{"verb": "result.emit", "summary": "send failed"}})
+            }
             return
-        emit([{"verb":"result.emit","summary":"unsupported"}])
-    if __name__ == "__main__":
-        main()
+        default:
+            emit([]map[string]any{{"verb": "result.emit", "summary": "unsupported"}})
+        }
+    }
     """
 }
diff --git a/packages/MCPServer/Sources/MCPServer/DockerImageInspector.swift b/packages/MCPServer/Sources/MCPServer/DockerImageInspector.swift
new file mode 100644
index 00000000..d242193a
--- /dev/null
+++ b/packages/MCPServer/Sources/MCPServer/DockerImageInspector.swift
@@ -0,0 +1,57 @@
+import Foundation
+import Structure
+
+/// Reads and verifies pinned Docker product image digests.
+public enum DockerImageInspector: Sendable {
+    public static func localImageID(
+        tag: String,
+        executor: @escaping DockerCLIExecutor
+    ) async throws -> DockerImageDigest {
+        let response = try await executor(
+            ["image", "inspect", "--format", "{{.Id}}", tag],
+            Data(),
+            30
+        )
+        guard response.exitCode == 0 else {
+            throw DockerImageDigestError.imageMissing(tag)
+        }
+        let raw = String(decoding: response.stdout, as: UTF8.self)
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+        guard let digest = DockerImageDigest(hexDigest: raw) else {
+            throw DockerImageDigestError.imageMissing(tag)
+        }
+        return digest
+    }
+
+    public static func verifyPinned(
+        tag: String,
+        expected: DockerImageDigest,
+        executor: @escaping DockerCLIExecutor
+    ) async throws {
+        let actual = try await localImageID(tag: tag, executor: executor)
+        guard actual == expected else {
+            throw DockerImageDigestError.digestMismatch(tag: tag, expected: expected, actual: actual)
+        }
+    }
+
+    /// Returns false when the image exists but predates required worker binaries.
+    public static func workerImageHasCurrentBinaries(
+        tag: String = DockerWorkerRuntime.image,
+        executor: @escaping DockerCLIExecutor
+    ) async -> Bool {
+        let format = "{{index .Config.Labels \"\(DockerWorkerRuntime.binariesLabelKey)\"}}"
+        do {
+            let response = try await executor(
+                ["image", "inspect", "--format", format, tag],
+                Data(),
+                30
+            )
+            guard response.exitCode == 0 else { return false }
+            let label = String(decoding: response.stdout, as: UTF8.self)
+                .trimmingCharacters(in: .whitespacesAndNewlines)
+            return label == DockerWorkerRuntime.binariesLabelValue
+        } catch {
+            return false
+        }
+    }
+}
diff --git a/packages/MCPServer/Sources/MCPServer/DockerProductImagePrewarmer.swift b/packages/MCPServer/Sources/MCPServer/DockerProductImagePrewarmer.swift
index 3522edc8..1c1b3403 100644
--- a/packages/MCPServer/Sources/MCPServer/DockerProductImagePrewarmer.swift
+++ b/packages/MCPServer/Sources/MCPServer/DockerProductImagePrewarmer.swift
@@ -2,30 +2,53 @@ import Foundation
 import DockerRunnerXPC
 import Structure
 
-/// Ensures trusted product Docker images exist (pull or local build).
+/// Ensures trusted product Docker images exist (local build) and match pinned digests.
 public enum DockerProductImagePrewarmer: Sendable {
-    public static func ensureWebCrawlerImage(
+    public static func ensureWorkerImage(
         executor: @escaping DockerCLIExecutor
     ) async throws {
         try await ensureImage(
-            tag: DockerProductImagePolicy.webCrawlerImage,
-            dockerfileRelativePath: DockerProductImagePolicy.webCrawlerDockerfileRelativePath,
-            contextRelativePath: DockerProductImagePolicy.webCrawlerBuildContextRelativePath,
+            tag: DockerProductImagePolicy.workerImage,
+            dockerfileRelativePath: DockerProductImagePolicy.workerDockerfileRelativePath,
+            contextRelativePath: DockerProductImagePolicy.workerBuildContextRelativePath,
+            pinnedDigest: DockerWorkerRuntime.pinnedDigest,
+            buildValidator: DockerProductImagePolicy.isAllowedWorkerBuild,
             executor: executor,
             buildTimeoutSeconds: 1_200
         )
     }
 
+    /// Legacy alias used by crawler startup paths.
+    public static func ensureWebCrawlerImage(
+        executor: @escaping DockerCLIExecutor
+    ) async throws {
+        try await ensureWorkerImage(executor: executor)
+    }
+
     public static func ensureImage(
         tag: String,
         dockerfileRelativePath: String,
         contextRelativePath: String,
+        pinnedDigest: DockerImageDigest,
+        buildValidator: @escaping (String, String, String) -> Bool,
         executor: @escaping DockerCLIExecutor,
         buildTimeoutSeconds: Int = 1_200
     ) async throws {
         let inspect = try await executor(["image", "inspect", tag], Data(), 30)
         if inspect.exitCode == 0 {
-            return
+            let binariesCurrent = await DockerImageInspector.workerImageHasCurrentBinaries(
+                tag: tag,
+                executor: executor
+            )
+            if binariesCurrent {
+                try await DockerImageInspector.verifyPinned(
+                    tag: tag,
+                    expected: pinnedDigest,
+                    executor: executor
+                )
+                return
+            }
+            // Stale worker image (missing required binaries). Rebuild overwrites the tag.
         }
 
         guard let repoRoot = DerrickRepositoryRoot.locate() else {
@@ -39,6 +62,9 @@ public enum DockerProductImagePrewarmer: Sendable {
         guard FileManager.default.fileExists(atPath: context.path) else {
             throw DockerProductImagePrewarmerError.dockerfileMissing(context.path)
         }
+        guard buildValidator(dockerfile.path, tag, context.path) else {
+            throw DockerProductImagePrewarmerError.buildFailed(tag, "build policy rejected image build")
+        }
 
         let build = try await executor(
             [
@@ -58,37 +84,23 @@ public enum DockerProductImagePrewarmer: Sendable {
                 detail.isEmpty ? "exit \(build.exitCode)" : detail
             )
         }
+
+        try await DockerImageInspector.verifyPinned(
+            tag: tag,
+            expected: pinnedDigest,
+            executor: executor
+        )
     }
 }
 
-/// One in-flight crawler image build per process.
-///
-/// Chat and daemon start this in the background. A `web.crawl` that arrives
-/// while it is still running waits on the same task and does not start a second
-/// `docker build`.
+/// Legacy alias gate — delegates to `WorkerImageGate` so crawler/script paths share one build.
 public actor WebCrawlerImageGate {
     public static let shared = WebCrawlerImageGate()
 
-    private var inFlight: Task<Void, Error>?
-
     public init() {}
 
     public func ensureReady(executor: @escaping DockerCLIExecutor) async throws {
-        if let inFlight {
-            try await inFlight.value
-            return
-        }
-        let task = Task {
-            try await DockerProductImagePrewarmer.ensureWebCrawlerImage(executor: executor)
-        }
-        inFlight = task
-        do {
-            try await task.value
-            inFlight = nil
-        } catch {
-            inFlight = nil
-            throw error
-        }
+        try await WorkerImageGate.shared.ensureReady(executor: executor)
     }
 }
 
@@ -97,8 +109,6 @@ public enum DockerProductImagePrewarmerError: Error, LocalizedError, Equatable,
     case dockerfileMissing(String)
     case buildFailed(String, String)
 
-    /// First compiler `error:` line, if the docker build log has one. Not shown as the
-    /// user-facing `errorDescription` (that stays a short human sentence).
     public var compilerDiagnostic: String? {
         switch self {
         case .buildFailed(_, let detail):
@@ -111,11 +121,11 @@ public enum DockerProductImagePrewarmerError: Error, LocalizedError, Equatable,
     public var errorDescription: String? {
         switch self {
         case .repositoryRootNotFound:
-            return "The web crawler image is not installed and Derrick could not find its source to build it."
+            return "The worker image is not installed and Derrick could not find its source to build it."
         case .dockerfileMissing:
-            return "The web crawler image is not installed and Derrick could not find its build files."
+            return "The worker image is not installed and Derrick could not find its build files."
         case .buildFailed:
-            return "Derrick could not build the web crawler image. Make sure Docker Desktop is running, has enough disk space, and can reach the network."
+            return "Derrick could not build the worker image. Make sure Docker Desktop is running, has enough disk space, and can reach the network."
         }
     }
 
diff --git a/packages/MCPServer/Sources/MCPServer/FileExtractorDockerExecutor.swift b/packages/MCPServer/Sources/MCPServer/FileExtractorDockerExecutor.swift
index 21abfdce..0d85bbf6 100644
--- a/packages/MCPServer/Sources/MCPServer/FileExtractorDockerExecutor.swift
+++ b/packages/MCPServer/Sources/MCPServer/FileExtractorDockerExecutor.swift
@@ -5,8 +5,9 @@ import Structure
 /// Own queue (max 1). Job folders are bind-mounted; the image must already
 /// exist (`docker image inspect` happens outside the permit).
 public struct FileExtractorDockerExecutor: Sendable {
-    public static let image = "derrick-file-extractor:swift-6.4-v1"
+    public static let image = DockerWorkerRuntime.image
     public static let containerPrefix = "derrick-file-extractor"
+    public static let binaryPath = DockerWorkerRuntime.extractorBinary
     public static let maximumTimeoutSeconds = 180
 
     private let executor: DockerCLIExecutor
@@ -27,10 +28,7 @@ public struct FileExtractorDockerExecutor: Sendable {
         timeoutSeconds: Int
     ) async throws -> DockerCLIResult {
         let timeout = min(max(timeoutSeconds, 1), Self.maximumTimeoutSeconds)
-        let imageCheck = try await executor(["image", "inspect", Self.image], Data(), 30)
-        guard imageCheck.exitCode == 0 else {
-            throw FileExtractorDockerExecutorError.imageUnavailable(Self.image)
-        }
+        try await WorkerImageGate.shared.ensureReady(executor: executor)
         let executor = self.executor
         do {
             return try await queue.withPermit {
@@ -48,7 +46,7 @@ public struct FileExtractorDockerExecutor: Sendable {
                     startStep: "start file extractor container",
                     body: { name in
                         try await executor(
-                            ["exec", "-i", name, "/usr/local/bin/derrick-file-extractor"],
+                            ["exec", "-i", name, Self.binaryPath],
                             input,
                             timeout
                         )
diff --git a/packages/MCPServer/Sources/MCPServer/FileExtractorToolModule.swift b/packages/MCPServer/Sources/MCPServer/FileExtractorToolModule.swift
index 21b09bae..35edd1f6 100644
--- a/packages/MCPServer/Sources/MCPServer/FileExtractorToolModule.swift
+++ b/packages/MCPServer/Sources/MCPServer/FileExtractorToolModule.swift
@@ -64,8 +64,17 @@ public enum FileExtractorToolModule: MCPToolModule {
                 let payload = try JSONEncoder().encode(workerRequest)
                 let dockerResult = try await run(payload, workspace, parsed.timeoutSeconds)
                 let workerJSON = String(decoding: dockerResult.stdout, as: UTF8.self)
-                let worker = (try? JSONDecoder().decode(FileExtractorWireResult.self, from: dockerResult.stdout))
-                    ?? FileExtractorWireResult(ok: false, files: [], diagnostics: [workerJSON])
+                let worker: FileExtractorWireResult
+                if (try? GuestContractValidation.validateFileExtractorResultJSON(dockerResult.stdout)) != nil {
+                    worker = (try? JSONDecoder().decode(FileExtractorWireResult.self, from: dockerResult.stdout))
+                        ?? FileExtractorWireResult(ok: false, files: [], diagnostics: [workerJSON])
+                } else {
+                    worker = FileExtractorWireResult(
+                        ok: false,
+                        files: [],
+                        diagnostics: ["File extractor returned invalid JSON output."]
+                    )
+                }
                 let exported = (try? workspace.publishOutputs()) ?? []
                 if dockerResult.exitCode != 0 && !worker.ok {
                     return try failure(
diff --git a/packages/MCPServer/Sources/MCPServer/Orchestration/JobOrchestrationToolModule.swift b/packages/MCPServer/Sources/MCPServer/Orchestration/JobOrchestrationToolModule.swift
index 629d0bc6..abdae01c 100644
--- a/packages/MCPServer/Sources/MCPServer/Orchestration/JobOrchestrationToolModule.swift
+++ b/packages/MCPServer/Sources/MCPServer/Orchestration/JobOrchestrationToolModule.swift
@@ -34,7 +34,7 @@ public enum JobOrchestrationToolModule {
                     ]),
                     "tool_arguments": .object([
                         "type": .string("object"),
-                        "description": .string("Frozen effector args. For web.crawl use {start_url,goal,max_pages,max_depth,timeout_seconds}. For script_exec use {description,reason,script} where script is standalone Python reading JSON from stdin and writing Derrick envelope JSON to stdout.")
+                        "description": .string("Frozen effector args. For web.crawl use {start_url,goal,max_pages,max_depth,timeout_seconds}. For script_exec use {description,reason,script} where script is standalone Go reading JSON from stdin and writing Derrick envelope JSON to stdout.")
                     ]),
                     "wake_after": .object([
                         "type": .string("boolean"),
diff --git a/packages/MCPServer/Sources/MCPServer/PluginFactoryToolModule.swift b/packages/MCPServer/Sources/MCPServer/PluginFactoryToolModule.swift
index baf82d7a..3bcb7363 100644
--- a/packages/MCPServer/Sources/MCPServer/PluginFactoryToolModule.swift
+++ b/packages/MCPServer/Sources/MCPServer/PluginFactoryToolModule.swift
@@ -18,7 +18,7 @@ public enum PluginFactoryToolModule: MCPToolModule {
                 ]),
                 "host_manifest_json": .object([
                     "type": .string("string"),
-                    "description": .string("Host-owned Agent Plugin plugin.json. When set, the builder only supplies Python and tests.")
+                    "description": .string("Host-owned Agent Plugin plugin.json. When set, the builder only supplies Go source and tests.")
                 ]),
             ]),
             "required": .array([.string("goal")])
diff --git a/packages/MCPServer/Sources/MCPServer/Script/GoGuestDockerExecutor.swift b/packages/MCPServer/Sources/MCPServer/Script/GoGuestDockerExecutor.swift
new file mode 100644
index 00000000..2c230202
--- /dev/null
+++ b/packages/MCPServer/Sources/MCPServer/Script/GoGuestDockerExecutor.swift
@@ -0,0 +1,266 @@
+import Foundation
+import Plugin
+import Structure
+
+/// Offline Go guest executor for `script_exec` and `plugin.invoke`.
+///
+/// Compiles `package main` source and runs the Linux binary inside the pinned
+/// worker image. Untrusted source never touches the host toolchain.
+public struct GoGuestDockerExecutor: Sendable {
+    public static let containerPrefix = "derrick-guest-runtime"
+    private static let compileTimeoutSeconds = 120
+    private static let writeTimeoutSeconds = 60
+
+    public let image: String
+    private let executor: DockerCLIExecutor
+    private let queue: DerrickDockerRunQueue
+
+    public init(
+        image: String = DockerWorkerRuntime.image,
+        executor: @escaping DockerCLIExecutor,
+        queue: DerrickDockerRunQueue = .guest
+    ) {
+        self.image = image.trimmingCharacters(in: .whitespacesAndNewlines)
+        self.executor = executor
+        self.queue = queue
+    }
+
+    /// Compile guest source in a one-shot container and return the Linux binary bytes.
+    public func compileSource(_ source: String) async throws -> Data {
+        try await WorkerImageGate.shared.ensureReady(executor: executor)
+        return try await withGuestContainer { name in
+            try await prepareCompiledGuest(source: source, in: name)
+            return try await readBinary(from: name)
+        }
+    }
+
+    /// Compile once, run once (factory single-hop path).
+    public func runSource(
+        source: String,
+        input: Data,
+        timeoutSeconds: Int = 300
+    ) async throws -> PluginFactoryExecutionResult {
+        try await withCompiledGuest(source: source) { name in
+            try await runCompiledGuest(
+                container: name,
+                input: input,
+                timeoutSeconds: timeoutSeconds
+            )
+        }
+    }
+
+    /// Compile once, then run the body with a live container name (multi-hop loops).
+    public func withCompiledGuest<T: Sendable>(
+        source: String,
+        _ body: @escaping @Sendable (String) async throws -> T
+    ) async throws -> T {
+        try await WorkerImageGate.shared.ensureReady(executor: executor)
+        return try await withGuestContainer { name in
+            try await prepareCompiledGuest(source: source, in: name)
+            return try await body(name)
+        }
+    }
+
+    /// Run a previously compiled guest binary in a one-shot container.
+    public func runArtifact(
+        artifact: Data,
+        input: Data,
+        timeoutSeconds: Int = 300
+    ) async throws -> PluginFactoryExecutionResult {
+        try await WorkerImageGate.shared.ensureReady(executor: executor)
+        return try await withGuestContainer { name in
+            try await write(binary: artifact, to: name)
+            return try await runCompiledGuest(
+                container: name,
+                input: input,
+                timeoutSeconds: timeoutSeconds
+            )
+        }
+    }
+
+    /// Execute `/tmp/guest` in an existing guest container.
+    public func runCompiledGuest(
+        container name: String,
+        input: Data,
+        timeoutSeconds: Int = 300
+    ) async throws -> PluginFactoryExecutionResult {
+        result(
+            from: try await executor(
+                [
+                    "exec", "-i", name,
+                    DockerWorkerRuntime.guestBinaryPath,
+                ],
+                input,
+                min(max(timeoutSeconds, 1), GuestRuntimeLimits.maxTimeoutSeconds)
+            )
+        )
+    }
+
+    private func prepareCompiledGuest(source: String, in container: String) async throws {
+        try await writeSource(source, to: container)
+        try await compileGuest(in: container)
+    }
+
+    private func withGuestContainer<T: Sendable>(
+        _ body: @escaping @Sendable (String) async throws -> T
+    ) async throws -> T {
+        try await DockerImageInspector.verifyPinned(
+            tag: image,
+            expected: DockerWorkerRuntime.pinnedDigest,
+            executor: executor
+        )
+        let image = self.image
+        let executor = self.executor
+        do {
+            return try await queue.withPermit {
+                try await OneshotDockerContainer.run(
+                    executor: executor,
+                    prefix: Self.containerPrefix,
+                    createArguments: { name in
+                        [
+                            "create",
+                        ] + DerrickDockerRuntimeIdentity.createLabelArguments + [
+                            "--network", "none",
+                            "--name", name,
+                            "--env", "HOME=/tmp",
+                            "--env", "GOCACHE=/tmp/gocache",
+                            "--env", "GOTMPDIR=/tmp",
+                            "--read-only",
+                            "--tmpfs", "/tmp:rw,exec,nosuid,size=256m",
+                            "--pids-limit", "128",
+                            "--cpus", "2.0",
+                            "--memory", "1g",
+                            "--security-opt", "no-new-privileges",
+                            "--cap-drop", "ALL",
+                            image,
+                            "/bin/sleep",
+                            "infinity",
+                        ]
+                    },
+                    createStep: "create go guest runtime container",
+                    startStep: "start go guest runtime container",
+                    body: body
+                )
+            }
+        } catch let error as OneshotDockerContainerError {
+            throw mappedGuestError(error)
+        }
+    }
+
+    private func writeSource(_ source: String, to container: String) async throws {
+        try check(
+            try await executor(
+                ["exec", "-i", container, "sh", "-c", DockerWorkerRuntime.guestWriteSourceShell],
+                Data(source.utf8),
+                Self.writeTimeoutSeconds
+            ),
+            step: "write Go guest source"
+        )
+    }
+
+    private func write(binary: Data, to container: String) async throws {
+        try check(
+            try await executor(
+                [
+                    "exec", "-i", container, "sh", "-c",
+                    "cat > \(DockerWorkerRuntime.guestBinaryPath) && chmod +x \(DockerWorkerRuntime.guestBinaryPath)",
+                ],
+                binary,
+                Self.writeTimeoutSeconds
+            ),
+            step: "write Go guest binary"
+        )
+    }
+
+    private func compileGuest(in container: String) async throws {
+        try check(
+            try await executor(
+                ["exec", container, "sh", "-c", DockerWorkerRuntime.guestCompileShell],
+                Data(),
+                Self.compileTimeoutSeconds
+            ),
+            step: "compile Go guest"
+        )
+    }
+
+    private func readBinary(from container: String) async throws -> Data {
+        let response = try await executor(
+            ["exec", container, "sh", "-c", DockerWorkerRuntime.guestReadBinaryShell],
+            Data(),
+            Self.writeTimeoutSeconds
+        )
+        try check(response, step: "read compiled Go guest")
+        guard !response.stdout.isEmpty else {
+            throw GoGuestDockerExecutorError.commandFailed(
+                "read compiled Go guest",
+                "compiled binary was empty"
+            )
+        }
+        return response.stdout
+    }
+
+    private func result(from response: DockerCLIResult) -> PluginFactoryExecutionResult {
+        PluginFactoryExecutionResult(
+            exitCode: response.exitCode,
+            stdout: response.stdout,
+            stderr: response.stderr
+        )
+    }
+
+    private func check(_ response: DockerCLIResult, step: String) throws {
+        guard response.exitCode == 0 else {
+            throw GoGuestDockerExecutorError.commandFailed(step, detail(from: response))
+        }
+    }
+
+    private func mappedGuestError(_ error: OneshotDockerContainerError) -> Error {
+        switch error {
+        case .commandFailed(let step, let detail):
+            return GoGuestDockerExecutorError.commandFailed(step, detail)
+        case .imageUnavailable:
+            return error
+        }
+    }
+
+    private func detail(from result: DockerCLIResult) -> String {
+        let stderr = String(decoding: result.stderr, as: UTF8.self)
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+        return stderr.isEmpty ? "exit \(result.exitCode)" : stderr
+    }
+}
+
+public enum GoGuestDockerExecutorError: Error, LocalizedError, Equatable, Sendable {
+    case commandFailed(String, String)
+
+    public var errorDescription: String? {
+        switch self {
+        case .commandFailed(let step, let detail):
+            return "\(step) failed: \(detail)"
+        }
+    }
+}
+
+/// Shared gate for worker image readiness (crawl, extract, plugin guest).
+public actor WorkerImageGate {
+    public static let shared = WorkerImageGate()
+
+    private var inFlight: Task<Void, Error>?
+
+    public func ensureReady(executor: @escaping DockerCLIExecutor) async throws {
+        if let inFlight {
+            try await inFlight.value
+            return
+        }
+        let task = Task {
+            try await DockerProductImagePrewarmer.ensureWorkerImage(executor: executor)
+        }
+        inFlight = task
+        do {
+            try await task.value
+            inFlight = nil
+        } catch {
+            inFlight = nil
+            throw error
+        }
+    }
+}
diff --git a/packages/MCPServer/Sources/MCPServer/Script/GoPluginFactoryDockerExecutor.swift b/packages/MCPServer/Sources/MCPServer/Script/GoPluginFactoryDockerExecutor.swift
new file mode 100644
index 00000000..cc8c9ab6
--- /dev/null
+++ b/packages/MCPServer/Sources/MCPServer/Script/GoPluginFactoryDockerExecutor.swift
@@ -0,0 +1,61 @@
+import Foundation
+import Plugin
+import Structure
+
+/// Production adapter for the Go plugin factory.
+public struct GoPluginFactoryDockerExecutor: PluginFactoryExecutor, PluginFactoryCompiledGuestExecutor, Sendable {
+    private let runtime: GoGuestDockerExecutor
+
+    public var image: String { runtime.image }
+
+    public init(
+        image: String = DockerWorkerRuntime.image,
+        executor: @escaping DockerCLIExecutor
+    ) {
+        runtime = GoGuestDockerExecutor(image: image, executor: executor)
+    }
+
+    public func runGuestSource(
+        source: String,
+        input: Data
+    ) async throws -> PluginFactoryExecutionResult {
+        try await runtime.runSource(source: source, input: input)
+    }
+
+    public func runGuestSourceHops(
+        source: String,
+        testInput: Data
+    ) async throws -> PluginFactoryHopTestRun {
+        let script = try PluginFactoryTestScript.parse(testInput)
+        return try await runtime.withCompiledGuest(source: source) { container in
+            var hopResults: [PluginFactoryExecutionResult] = []
+            var lastResult = PluginFactoryExecutionResult(exitCode: 1)
+
+            for hop in script.hops {
+                let input = try hop.encodeValidated()
+                let result = try await runtime.runCompiledGuest(
+                    container: container,
+                    input: input
+                )
+                hopResults.append(result)
+                lastResult = result
+                guard result.exitCode == 0 else {
+                    return PluginFactoryHopTestRun(final: result, hopResults: hopResults)
+                }
+            }
+
+            return PluginFactoryHopTestRun(final: lastResult, hopResults: hopResults)
+        }
+    }
+
+    public func packageGuestSource(source: String) async throws -> Data {
+        try await runtime.compileSource(source)
+    }
+
+    public func runPackagedArtifact(
+        _ artifact: Data,
+        input: Data
+    ) async throws -> PluginFactoryExecutionResult {
+        try await runtime.runArtifact(artifact: artifact, input: input)
+    }
+}
diff --git a/packages/MCPServer/Sources/MCPServer/Script/GoScriptVerifier.swift b/packages/MCPServer/Sources/MCPServer/Script/GoScriptVerifier.swift
new file mode 100644
index 00000000..7a3acb17
--- /dev/null
+++ b/packages/MCPServer/Sources/MCPServer/Script/GoScriptVerifier.swift
@@ -0,0 +1,17 @@
+import Foundation
+import Plugin
+import Structure
+
+/// Conservative source checks for standalone Go guest scripts.
+public enum GoScriptVerifier: Sendable {
+    public static func validate(
+        source: String,
+        dependencies: [String: String] = [:]
+    ) -> [String] {
+        var findings = GuestGoSourceValidator.validate(source: source)
+        if !dependencies.isEmpty {
+            findings.append("Guest script dependencies are not supported.")
+        }
+        return findings
+    }
+}
diff --git a/packages/MCPServer/Sources/MCPServer/Script/GuestHopLoop.swift b/packages/MCPServer/Sources/MCPServer/Script/GuestHopLoop.swift
index 070b6625..ed9aae65 100644
--- a/packages/MCPServer/Sources/MCPServer/Script/GuestHopLoop.swift
+++ b/packages/MCPServer/Sources/MCPServer/Script/GuestHopLoop.swift
@@ -2,7 +2,7 @@ import Foundation
 import Plugin
 import Structure
 
-/// Shared host hop loop for offline Python guest programs.
+/// Shared host hop loop for offline Go guest programs.
 public enum GuestHopLoop: Sendable {
     public typealias HTTPResultEventBuilder = @Sendable (
         [PluginEnvelope],
@@ -62,6 +62,7 @@ public enum GuestHopLoop: Sendable {
                 }
                 lastSummary = envelope.payload["summary"]?.stringValue
                     ?? envelope.payload["content"]?.stringValue
+                    ?? envelope.payload["markdown"]?.stringValue
                     ?? envelope.payload["html"]?.stringValue
                     ?? envelope.payload["text"]?.stringValue
                     ?? envelope.payload["title"]?.stringValue
diff --git a/packages/MCPServer/Sources/MCPServer/Script/GuestPluginRunner.swift b/packages/MCPServer/Sources/MCPServer/Script/GuestPluginRunner.swift
index 54dd21d9..207bc7f7 100644
--- a/packages/MCPServer/Sources/MCPServer/Script/GuestPluginRunner.swift
+++ b/packages/MCPServer/Sources/MCPServer/Script/GuestPluginRunner.swift
@@ -2,7 +2,7 @@ import Foundation
 import Plugin
 import Structure
 
-/// Runs an approved factory release through the offline Python guest runtime.
+/// Runs an approved factory release through the offline Go guest runtime.
 public enum GuestPluginRunner: Sendable {
     public static func run(
         release: PluginFactoryRelease,
@@ -15,14 +15,20 @@ public enum GuestPluginRunner: Sendable {
         let invokeID = UUID().uuidString
         let initialEvent = (try? PluginHopEvent.decodeValidated(input))
             ?? PluginHopEvent(kind: .manual)
-        let executor = PythonGuestDockerExecutor(executor: dockerExecutor)
+        let executor = GoGuestDockerExecutor(executor: dockerExecutor)
+        guard !release.compiledArtifact.isEmpty else {
+            throw GoGuestDockerExecutorError.commandFailed(
+                "load plugin artifact",
+                "compiled artifact is empty"
+            )
+        }
         return try await GuestHopLoop.runForPluginInvoke(
             initialEvent: initialEvent,
             invokeID: invokeID,
             timeoutSeconds: timeoutSeconds,
             execute: { hopInput in
-                try await executor.runSource(
-                    source: release.guestSource,
+                try await executor.runArtifact(
+                    artifact: release.compiledArtifact,
                     input: hopInput,
                     timeoutSeconds: timeoutSeconds
                 )
diff --git a/packages/MCPServer/Sources/MCPServer/Script/HostHTTPClient.swift b/packages/MCPServer/Sources/MCPServer/Script/HostHTTPClient.swift
index 629c803c..b7069634 100644
--- a/packages/MCPServer/Sources/MCPServer/Script/HostHTTPClient.swift
+++ b/packages/MCPServer/Sources/MCPServer/Script/HostHTTPClient.swift
@@ -62,7 +62,7 @@ public actor HostHTTPClient {
         guard !trimmed.isEmpty, let url = URL(string: wireURL), url.scheme != nil, url.host != nil else {
             return HostHTTPFetch(status: 0, headers: [:], body: "", error: "invalid_url")
         }
-        var currentURL = url
+        var currentURL = NewsSourceURL.canonicalFetchURL(url)
         var currentMethod = request.method
         var currentBody = wire.body
         let envelopeHeaders = wire.headers
diff --git a/packages/MCPServer/Sources/MCPServer/Script/PythonGuestDockerExecutor.swift b/packages/MCPServer/Sources/MCPServer/Script/PythonGuestDockerExecutor.swift
deleted file mode 100644
index ad464879..00000000
--- a/packages/MCPServer/Sources/MCPServer/Script/PythonGuestDockerExecutor.swift
+++ /dev/null
@@ -1,133 +0,0 @@
-import Foundation
-import Plugin
-import Structure
-
-/// Offline Python guest executor for script_exec and plugin.invoke.
-///
-/// Recreate-on-handoff: one fresh `--network none` container per run, deleted
-/// when the hop loop finishes (host done). The image is reused if already pulled.
-public struct PythonGuestDockerExecutor: Sendable {
-    public static let containerPrefix = "derrick-guest-runtime"
-
-    public let image: String
-    private let executor: DockerCLIExecutor
-    private let queue: DerrickDockerRunQueue
-
-    public init(
-        image: String = DerrickGuestRuntime.pythonGuestDockerImage,
-        executor: @escaping DockerCLIExecutor,
-        queue: DerrickDockerRunQueue = .guest
-    ) {
-        self.image = image.trimmingCharacters(in: .whitespacesAndNewlines)
-        self.executor = executor
-        self.queue = queue
-    }
-
-    public func runSource(
-        source: String,
-        input: Data,
-        timeoutSeconds: Int = 300
-    ) async throws -> PluginFactoryExecutionResult {
-        try await withGuestContainer { name in
-            try await write(source: Data(source.utf8), to: name)
-            return result(
-                from: try await executor(
-                    ["exec", "-i", name, "python3", "/tmp/guest.py"],
-                    input,
-                    min(max(timeoutSeconds, 1), GuestRuntimeLimits.maxTimeoutSeconds)
-                )
-            )
-        }
-    }
-
-    private func withGuestContainer<T: Sendable>(
-        _ body: @escaping @Sendable (String) async throws -> T
-    ) async throws -> T {
-        try await OneshotDockerContainer.ensurePulledImage(image, executor: executor)
-        let image = self.image
-        let executor = self.executor
-        do {
-            return try await queue.withPermit {
-                try await OneshotDockerContainer.run(
-                    executor: executor,
-                    prefix: Self.containerPrefix,
-                    createArguments: { name in
-                        [
-                            "create",
-                        ] + DerrickDockerRuntimeIdentity.createLabelArguments + [
-                            "--network", "none",
-                            "--name", name,
-                            "--env", "HOME=/tmp",
-                            "--read-only",
-                            "--tmpfs", "/tmp:rw,exec,nosuid,size=128m",
-                            "--pids-limit", "128",
-                            "--cpus", "2.0",
-                            "--memory", "1g",
-                            "--security-opt", "no-new-privileges",
-                            "--cap-drop", "ALL",
-                            image,
-                            "/bin/sleep",
-                            "infinity",
-                        ]
-                    },
-                    createStep: "create guest runtime container",
-                    startStep: "start guest runtime container",
-                    body: body
-                )
-            }
-        } catch let error as OneshotDockerContainerError {
-            throw mappedGuestError(error)
-        }
-    }
-
-    private func write(source: Data, to container: String) async throws {
-        try check(
-            try await executor(
-                ["exec", "-i", container, "sh", "-c", "cat > /tmp/guest.py"],
-                source,
-                60
-            ),
-            step: "write Python source"
-        )
-    }
-
-    private func result(from response: DockerCLIResult) -> PluginFactoryExecutionResult {
-        PluginFactoryExecutionResult(
-            exitCode: response.exitCode,
-            stdout: response.stdout,
-            stderr: response.stderr
-        )
-    }
-
-    private func check(_ response: DockerCLIResult, step: String) throws {
-        guard response.exitCode == 0 else {
-            throw PythonGuestDockerExecutorError.commandFailed(step, detail(from: response))
-        }
-    }
-
-    private func mappedGuestError(_ error: OneshotDockerContainerError) -> Error {
-        switch error {
-        case .commandFailed(let step, let detail):
-            return PythonGuestDockerExecutorError.commandFailed(step, detail)
-        case .imageUnavailable:
-            return error
-        }
-    }
-
-    private func detail(from result: DockerCLIResult) -> String {
-        let stderr = String(decoding: result.stderr, as: UTF8.self)
-            .trimmingCharacters(in: .whitespacesAndNewlines)
-        return stderr.isEmpty ? "exit \(result.exitCode)" : stderr
-    }
-}
-
-public enum PythonGuestDockerExecutorError: Error, LocalizedError, Equatable, Sendable {
-    case commandFailed(String, String)
-
-    public var errorDescription: String? {
-        switch self {
-        case .commandFailed(let step, let detail):
-            return "\(step) failed: \(detail)"
-        }
-    }
-}
diff --git a/packages/MCPServer/Sources/MCPServer/Script/PythonPluginFactoryDockerExecutor.swift b/packages/MCPServer/Sources/MCPServer/Script/PythonPluginFactoryDockerExecutor.swift
deleted file mode 100644
index d52be34d..00000000
--- a/packages/MCPServer/Sources/MCPServer/Script/PythonPluginFactoryDockerExecutor.swift
+++ /dev/null
@@ -1,41 +0,0 @@
-import Foundation
-import Plugin
-import Structure
-
-/// Production adapter for the Python factory.
-public struct PythonPluginFactoryDockerExecutor: PluginFactoryExecutor, Sendable {
-    private let runtime: PythonGuestDockerExecutor
-
-    public var image: String { runtime.image }
-
-    public init(
-        image: String = DerrickGuestRuntime.pythonGuestDockerImage,
-        executor: @escaping DockerCLIExecutor
-    ) {
-        runtime = PythonGuestDockerExecutor(image: image, executor: executor)
-    }
-
-    public func runGuestSource(
-        source: String,
-        input: Data
-    ) async throws -> PluginFactoryExecutionResult {
-        try await runtime.runSource(source: source, input: input)
-    }
-
-    public func packageGuestSource(source: String) async throws -> Data {
-        Data(source.utf8)
-    }
-
-    public func runPackagedArtifact(
-        _ artifact: Data,
-        input: Data
-    ) async throws -> PluginFactoryExecutionResult {
-        guard let source = String(data: artifact, encoding: .utf8) else {
-            throw PythonGuestDockerExecutorError.commandFailed(
-                "decode Python artifact",
-                "artifact is not valid UTF-8"
-            )
-        }
-        return try await runtime.runSource(source: source, input: input)
-    }
-}
diff --git a/packages/MCPServer/Sources/MCPServer/Script/PythonScriptVerifier.swift b/packages/MCPServer/Sources/MCPServer/Script/PythonScriptVerifier.swift
deleted file mode 100644
index 8825d2bf..00000000
--- a/packages/MCPServer/Sources/MCPServer/Script/PythonScriptVerifier.swift
+++ /dev/null
@@ -1,13 +0,0 @@
-import Foundation
-import Plugin
-import Structure
-
-/// Conservative source checks for standalone Python guest scripts.
-public enum PythonScriptVerifier: Sendable {
-    public static func validate(
-        source: String,
-        dependencies: [String: String] = [:]
-    ) -> [String] {
-        GuestPythonSourceValidator.validate(source: source, dependencies: dependencies)
-    }
-}
diff --git a/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionRuntime.swift b/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionRuntime.swift
index 5145a427..c1a380d7 100644
--- a/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionRuntime.swift
+++ b/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionRuntime.swift
@@ -3,7 +3,7 @@ import MCP
 import Plugin
 import Structure
 
-/// Runs standalone Python guest source and dispatches host-owned capability hops.
+/// Runs standalone Go guest source and dispatches host-owned capability hops.
 public enum ScriptExecutionRuntime {
     public static func run(
         arguments: [String: Value],
@@ -16,12 +16,12 @@ public enum ScriptExecutionRuntime {
     ) async throws -> String {
         let started = Date()
         let parsed = try parse(arguments)
-        let language = GuestScriptLanguage.python
+        let language = GuestScriptLanguage.go
         logger("[script_exec] \(language.rawValue) source chars=\(parsed.script.count)")
 
         if GuestScriptLanguage.requestedLanguageIsUnsupported(arguments) {
             return finish(blocked(
-                findings: ["script_exec only runs Python. Swift guest scripts are not supported."],
+                findings: ["script_exec only runs Go. Python and other guest languages are not supported."],
                 stage: .staticValidation,
                 started: started,
                 parsed: parsed,
@@ -30,7 +30,7 @@ public enum ScriptExecutionRuntime {
         }
 
         let staticStarted = Date()
-        let staticFindings = PythonScriptVerifier.validate(
+        let staticFindings = GoScriptVerifier.validate(
             source: parsed.script,
             dependencies: parsed.dependencies
         )
@@ -113,30 +113,34 @@ public enum ScriptExecutionRuntime {
             logger("[script_exec] skipping LLM reviewer")
         }
 
+        let compileStarted = Date()
         let timeout = GuestRuntimeLimits.effectiveScriptTimeoutSeconds(
             requested: parsed.timeoutSeconds
         )
         let invokeID = UUID().uuidString
         do {
-            let executor = PythonGuestDockerExecutor(executor: stdinExecutor)
-            let result = try await GuestHopLoop.run(
-                initialEvent: initialEvent,
-                invokeID: invokeID,
-                timeoutSeconds: timeout,
-                verifier: language.verifierID,
-                execute: { input in
-                    try await executor.runSource(
-                        source: parsed.script,
-                        input: input,
-                        timeoutSeconds: timeout
-                    )
-                },
-                logger: logger,
-                hopHandler: hopHandler
-            )
+            let executor = GoGuestDockerExecutor(executor: stdinExecutor)
+            let result = try await executor.withCompiledGuest(source: parsed.script) { container in
+                try await GuestHopLoop.run(
+                    initialEvent: initialEvent,
+                    invokeID: invokeID,
+                    timeoutSeconds: timeout,
+                    verifier: language.verifierID,
+                    execute: { input in
+                        try await executor.runCompiledGuest(
+                            container: container,
+                            input: input,
+                            timeoutSeconds: timeout
+                        )
+                    },
+                    logger: logger,
+                    hopHandler: hopHandler
+                )
+            }
+            let compileMS = ScriptPhaseTiming.elapsedMS(from: compileStarted)
             let metrics = ScriptPhaseTiming.scriptMetrics(parsed.script)
             var phaseTiming = result.phaseTiming ?? ScriptPhaseTiming()
-            phaseTiming.staticValidateMS = staticValidateMS
+            phaseTiming.staticValidateMS = staticValidateMS + compileMS
             phaseTiming.totalMS = ScriptPhaseTiming.elapsedMS(from: started)
             phaseTiming.scriptCharCount = metrics.chars
             phaseTiming.scriptLineCount = metrics.lines
@@ -156,11 +160,17 @@ public enum ScriptExecutionRuntime {
                 phaseTiming: phaseTiming
             )
             return finish(decorated, logger: logger)
-        } catch let error as PythonGuestDockerExecutorError {
+        } catch let error as GoGuestDockerExecutorError {
             logger("[script_exec] guest runtime failed: \(error.localizedDescription)")
+            let stage: ScriptFailureStage
+            if case .commandFailed(let step, _) = error, step.contains("compile") {
+                stage = .typecheck
+            } else {
+                stage = .execution
+            }
             return finish(runtimeFailure(
                 findings: [error.localizedDescription],
-                stage: .execution,
+                stage: stage,
                 started: started,
                 parsed: parsed,
                 assessment: reviewerAssessment,
diff --git a/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionSupport.swift b/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionSupport.swift
index 87272b17..322efb92 100644
--- a/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionSupport.swift
+++ b/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionSupport.swift
@@ -144,8 +144,8 @@ public enum ScriptExecutionVerifier {
 
     private static func readonlyViolations(in script: String) -> [String] {
         let patterns: [(String, String)] = [
-            (#"(?m)\bopen\s*\("#, "Readonly mode cannot mutate filesystem."),
-            (#"(?m)\b(subprocess|os\.system|os\.popen|socket|urllib|requests|httpx)\b"#, "Readonly mode cannot execute nested commands or access the network.")
+            (#"os\.(Open|ReadFile|WriteFile|Remove|Create|Mkdir)"#, "Readonly mode cannot mutate filesystem."),
+            (#"\"net/http\"|\"net\"|exec\.Command|crypto/tls"#, "Readonly mode cannot execute nested commands or access the network.")
         ]
         return patterns.compactMap { pattern, message in
             script.range(of: pattern, options: .regularExpression) != nil ? message : nil
@@ -159,7 +159,7 @@ extension ScriptExecutionResult {
         durationMS: Int,
         maxSeconds: Int = GuestRuntimeLimits.containerRunMaxTTLSeconds,
         phaseTiming: ScriptPhaseTiming? = nil,
-        verifier: String = "python-check-v1"
+        verifier: String = "go-check-v1"
     ) -> ScriptExecutionResult {
         let explanation = GuestRuntimeLimits.containerLeaseExceededExplanation(maxSeconds: maxSeconds)
         return ScriptExecutionResult(
diff --git a/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionToolModule.swift b/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionToolModule.swift
index 12e2e3db..dd3c4741 100644
--- a/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionToolModule.swift
+++ b/packages/MCPServer/Sources/MCPServer/Script/ScriptExecutionToolModule.swift
@@ -20,11 +20,11 @@ public enum ScriptExecutionToolModule: MCPToolModule {
                 ]),
                 "script": .object([
                     "type": .string("string"),
-                    "description": .string("Standalone Python source. Reads one JSON event from standard input and writes a JSON array of Derrick envelopes to standard output. Use http.request envelopes for host HTTP and result.emit/message.post for terminal output.")
+                    "description": .string("Standalone Go `package main` source. Reads one hop-event JSON object from standard input and writes an envelope-list JSON array to standard output. Use http.request envelopes for host HTTP and result.emit/message.post for terminal output.")
                 ]),
                 "language": .object([
                     "type": .string("string"),
-                    "description": .string("Must be python when set. Swift guest scripts are not supported.")
+                    "description": .string("Must be go when set. Python and Swift guest scripts are not supported.")
                 ]),
                 "user_prompt": .object([
                     "type": .string("string"),
diff --git a/packages/MCPServer/Sources/MCPServer/Script/SystemInstruction.swift b/packages/MCPServer/Sources/MCPServer/Script/SystemInstruction.swift
index 6ea9c131..a05bfb75 100644
--- a/packages/MCPServer/Sources/MCPServer/Script/SystemInstruction.swift
+++ b/packages/MCPServer/Sources/MCPServer/Script/SystemInstruction.swift
@@ -9,5 +9,5 @@ import Foundation
 import Structure
 
 public var ReviewerSystemPrompt: String {
-    DerrickBundledText.mustLoad("script_reviewer_instructions.md")
+    ScriptExecContractPrompts.reviewerGuide()
 }
diff --git a/packages/MCPServer/Sources/MCPServer/WebCrawlerDockerExecutor.swift b/packages/MCPServer/Sources/MCPServer/WebCrawlerDockerExecutor.swift
index c53322be..1b8ca9e0 100644
--- a/packages/MCPServer/Sources/MCPServer/WebCrawlerDockerExecutor.swift
+++ b/packages/MCPServer/Sources/MCPServer/WebCrawlerDockerExecutor.swift
@@ -7,23 +7,20 @@ import Structure
 /// The image is trusted product code. User input is passed only as JSON on
 /// stdin; it is never interpolated into a shell command.
 public struct WebCrawlerDockerExecutor: Sendable {
-    public static let image = "derrick-web-crawler:swift-6.4-v1"
+    public static let image = DockerWorkerRuntime.image
     public static let containerPrefix = "derrick-web-crawler"
+    public static let binaryPath = DockerWorkerRuntime.crawlerBinary
     public static let maximumTimeoutSeconds = 900
     public static let dockerNetwork = "bridge"
 
     private let executor: DockerCLIExecutor
     private let queue: DerrickDockerRunQueue
-    private let imageGate: WebCrawlerImageGate
-
     public init(
         executor: @escaping DockerCLIExecutor,
-        queue: DerrickDockerRunQueue = .crawler,
-        imageGate: WebCrawlerImageGate = .shared
+        queue: DerrickDockerRunQueue = .crawler
     ) {
         self.executor = executor
         self.queue = queue
-        self.imageGate = imageGate
     }
 
     public func run(
@@ -31,7 +28,7 @@ public struct WebCrawlerDockerExecutor: Sendable {
         timeoutSeconds: Int
     ) async throws -> DockerCLIResult {
         let timeout = min(max(timeoutSeconds, 1), Self.maximumTimeoutSeconds)
-        try await imageGate.ensureReady(executor: executor)
+        try await WorkerImageGate.shared.ensureReady(executor: executor)
         let prepared = try await WebCrawlerDockerInputPreparer.enrich(input)
         let executor = self.executor
         do {
@@ -53,7 +50,7 @@ public struct WebCrawlerDockerExecutor: Sendable {
                         startStep: "start crawler container",
                         body: { name in
                             try await executor(
-                                ["exec", "-i", name, "/usr/local/bin/derrick-web-crawler"],
+                                ["exec", "-i", name, Self.binaryPath],
                                 prepared.data,
                                 timeout
                             )
diff --git a/packages/MCPServer/Sources/MCPServer/WebCrawlerToolModule.swift b/packages/MCPServer/Sources/MCPServer/WebCrawlerToolModule.swift
index 2c6bc083..bfa60b2b 100644
--- a/packages/MCPServer/Sources/MCPServer/WebCrawlerToolModule.swift
+++ b/packages/MCPServer/Sources/MCPServer/WebCrawlerToolModule.swift
@@ -63,6 +63,17 @@ public enum WebCrawlerToolModule: MCPToolModule {
                     ).encodedJSON()
                 }
 
+                do {
+                    try GuestContractValidation.validateWebCrawlerResultJSON(dockerResult.stdout)
+                } catch {
+                    return try failure(
+                        status: .failed,
+                        stage: .execution,
+                        code: "web_crawl_invalid_output",
+                        message: "Crawler returned invalid JSON output."
+                    ).encodedJSON()
+                }
+
                 guard let result = try? JSONDecoder().decode(
                     WebCrawlerWireResult.self,
                     from: dockerResult.stdout
@@ -138,15 +149,16 @@ public enum WebCrawlerToolModule: MCPToolModule {
         let timeoutSeconds = intValue(arguments["timeout_seconds"]) ?? 120
 
         guard !startURL.isEmpty else { throw WebCrawlerToolError.invalidStartURL }
-        guard let url = URL(string: startURL),
-              let scheme = url.scheme?.lowercased(),
+        guard let rawURL = URL(string: startURL),
+              let scheme = rawURL.scheme?.lowercased(),
               scheme == "http" || scheme == "https",
-              url.host?.isEmpty == false,
-              url.user == nil,
-              url.password == nil
+              rawURL.host?.isEmpty == false,
+              rawURL.user == nil,
+              rawURL.password == nil
         else {
             throw WebCrawlerToolError.invalidStartURL
         }
+        let url = NewsSourceURL.canonicalFetchURL(rawURL, contextHint: goal)
         guard !goal.isEmpty else { throw WebCrawlerToolError.emptyGoal }
         guard goal.count <= 2_000 else { throw WebCrawlerToolError.goalTooLong }
         if let reason = maliciousGoalReason(goal) {
@@ -163,7 +175,7 @@ public enum WebCrawlerToolModule: MCPToolModule {
         }
 
         return WebCrawlerWireRequest(
-            startURL: startURL,
+            startURL: url.absoluteString,
             goal: goal,
             maxPages: maxPages,
             maxDepth: maxDepth,
@@ -274,6 +286,13 @@ private struct WebCrawlerWireResult: Decodable, Sendable {
         case stopReason = "stop_reason"
         case diagnostics
     }
+
+    init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        ok = try container.decode(Bool.self, forKey: .ok)
+        stopReason = try container.decode(String.self, forKey: .stopReason)
+        diagnostics = try container.decodeIfPresent([String].self, forKey: .diagnostics) ?? []
+    }
 }
 
 private enum WebCrawlerToolError: Error, LocalizedError, Sendable {
diff --git a/packages/MCPServer/Sources/SlackConnectorE2EHarness/E2EEnvironment.swift b/packages/MCPServer/Sources/SlackConnectorE2EHarness/E2EEnvironment.swift
index f26bde73..dac39f40 100644
--- a/packages/MCPServer/Sources/SlackConnectorE2EHarness/E2EEnvironment.swift
+++ b/packages/MCPServer/Sources/SlackConnectorE2EHarness/E2EEnvironment.swift
@@ -271,7 +271,7 @@ struct E2EEnvironment {
         let goal = input.connectorBuildGoal(crawlSummary: SlackConnectorFactoryInput.defaultCrawlSummary)
 
         fputs("[E2E] factory build scope=\(scope.rawValue)…\n", stderr)
-        let executor = PythonPluginFactoryDockerExecutor(executor: dockerExecutor)
+        let executor = GoPluginFactoryDockerExecutor(executor: dockerExecutor)
         let release = try await PluginFactorySession(
             configuration: PluginFactoryConfiguration(maxBuilderAttempts: 5)
         ).build(
diff --git a/packages/MCPServer/Sources/SlackConnectorInstallReference/SlackConnectorInstallReferenceMain.swift b/packages/MCPServer/Sources/SlackConnectorInstallReference/SlackConnectorInstallReferenceMain.swift
index 7c72d075..9fd283b6 100644
--- a/packages/MCPServer/Sources/SlackConnectorInstallReference/SlackConnectorInstallReferenceMain.swift
+++ b/packages/MCPServer/Sources/SlackConnectorInstallReference/SlackConnectorInstallReferenceMain.swift
@@ -83,7 +83,7 @@ enum SlackConnectorInstallReference {
             userGoal: goal,
             hostManifest: input.hostManifest,
             builder: E2EFactoryBuilder(scope: .fullSync),
-            executor: PythonPluginFactoryDockerExecutor(executor: dockerExecutor),
+            executor: GoPluginFactoryDockerExecutor(executor: dockerExecutor),
             reviewer: E2EHarnessReviewer(),
             logger: { fputs("\($0)\n", stderr) }
         )
diff --git a/packages/MCPServer/Sources/SlackConnectorLiveHarness/LiveHarnessEnvironment.swift b/packages/MCPServer/Sources/SlackConnectorLiveHarness/LiveHarnessEnvironment.swift
index 06aa406e..202ed356 100644
--- a/packages/MCPServer/Sources/SlackConnectorLiveHarness/LiveHarnessEnvironment.swift
+++ b/packages/MCPServer/Sources/SlackConnectorLiveHarness/LiveHarnessEnvironment.swift
@@ -79,7 +79,7 @@ struct LiveHarnessEnvironment {
         let goal = input.connectorBuildGoal(crawlSummary: SlackConnectorFactoryInput.defaultCrawlSummary)
 
         fputs("[live] building full-sync connector via LLM factory…\n", stderr)
-        let executor = PythonPluginFactoryDockerExecutor(executor: dockerExecutor)
+        let executor = GoPluginFactoryDockerExecutor(executor: dockerExecutor)
         let release = try await PluginFactorySession(
             configuration: PluginFactoryConfiguration(maxBuilderAttempts: 3)
         ).build(
diff --git a/packages/MCPServer/Tests/MCPServerTests/MCPServerTests.swift b/packages/MCPServer/Tests/MCPServerTests/MCPServerTests.swift
index 1896241f..b3970914 100644
--- a/packages/MCPServer/Tests/MCPServerTests/MCPServerTests.swift
+++ b/packages/MCPServer/Tests/MCPServerTests/MCPServerTests.swift
@@ -7,21 +7,109 @@ import Plugin
 import WebCrawler
 @testable import MCPServer
 
-@Suite struct MCPServerTests {
-    private static let dummyPythonScript = """
-        import json, sys
-        _ = sys.stdin.read()
-        json.dump([{"verb":"result.emit","summary":"ok"}], sys.stdout)
+@Suite(.serialized) struct MCPServerTests {
+    private static let dummyGoScript = """
+        package main
+
+        import (
+            "encoding/json"
+            "os"
+        )
+
+        func main() {
+            var event map[string]any
+            _ = json.NewDecoder(os.Stdin).Decode(&event)
+            enc := json.NewEncoder(os.Stdout)
+            enc.SetEscapeHTML(false)
+            _ = enc.Encode([]map[string]any{{"verb": "result.emit", "summary": "ok"}})
+        }
         """
 
-    private static let dummyStdin: @Sendable ([String], Data, Int) async throws -> DockerCLIResult = { arguments, _, _ in
-        if arguments.contains("python3"), arguments.contains("/tmp/guest.py") {
+    private static func isGuestBinaryExec(_ arguments: [String]) -> Bool {
+        arguments.contains(DockerWorkerRuntime.guestBinaryPath)
+            && !arguments.contains("cat >")
+    }
+
+    private static func mockWorkerImageInspect(_ arguments: [String]) -> DockerCLIResult? {
+        guard arguments.first == "image", arguments.contains("inspect") else {
+            return nil
+        }
+        if arguments.contains("{{.Id}}") {
+            let digest = DockerWorkerRuntime.pinnedDigest.rawValue + "\n"
+            return DockerCLIResult(exitCode: 0, stdout: Data(digest.utf8), stderr: Data())
+        }
+        if arguments.contains(where: { $0.contains(DockerWorkerRuntime.binariesLabelKey) }) {
+            let label = DockerWorkerRuntime.binariesLabelValue + "\n"
+            return DockerCLIResult(exitCode: 0, stdout: Data(label.utf8), stderr: Data())
+        }
+        return DockerCLIResult(exitCode: 0, stdout: Data("[]".utf8), stderr: Data())
+    }
+
+    private actor ImageBuildLatch {
+        private(set) var succeeded = false
+        func markSucceeded() { succeeded = true }
+    }
+
+    private static func missingUntilBuiltExecutor(
+        recorder: DockerCallRecorder,
+        latch: ImageBuildLatch,
+        failFirstBuild: Bool = false,
+        buildDelay: Duration? = nil
+    ) -> DockerCLIExecutor {
+        { args, _, _ in
+            await recorder.append(args)
+            if args.first == "build" {
+                if let buildDelay {
+                    try await Task.sleep(for: buildDelay)
+                }
+                if failFirstBuild {
+                    let builds = await recorder.calls.filter { $0.first == "build" }.count
+                    if builds == 1 {
+                        return DockerCLIResult(exitCode: 1, stdout: Data(), stderr: Data("boom".utf8))
+                    }
+                }
+                await latch.markSucceeded()
+                return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
+            }
+            if args.first == "image" {
+                if await latch.succeeded, let mocked = mockWorkerImageInspect(args) {
+                    return mocked
+                }
+                return DockerCLIResult(exitCode: 1, stdout: Data(), stderr: Data())
+            }
+            return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
+        }
+    }
+
+    private static let dummyCompiledGuest = Data([0x7f, 0x45, 0x4c, 0x46, 0x02])
+
+    private static func mockGuestDocker(_ arguments: [String]) -> DockerCLIResult? {
+        if arguments.contains("cat > /tmp/guest") {
+            return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
+        }
+        if arguments.contains(DockerWorkerRuntime.guestWriteSourceShell) {
+            return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
+        }
+        if arguments.contains(DockerWorkerRuntime.guestCompileShell) {
+            return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
+        }
+        if arguments.contains(DockerWorkerRuntime.guestReadBinaryShell) {
+            return DockerCLIResult(exitCode: 0, stdout: dummyCompiledGuest, stderr: Data())
+        }
+        if isGuestBinaryExec(arguments) {
             return DockerCLIResult(
                 exitCode: 0,
                 stdout: Data(#"[{"verb":"result.emit","summary":"ok"}]"#.utf8),
                 stderr: Data()
             )
         }
+        return mockWorkerImageInspect(arguments)
+    }
+
+    private static let dummyStdin: @Sendable ([String], Data, Int) async throws -> DockerCLIResult = { arguments, _, _ in
+        if let mocked = mockGuestDocker(arguments) {
+            return mocked
+        }
         return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
     }
 
@@ -234,46 +322,57 @@ import WebCrawler
         #expect(allowed?.contains("docs.slack.dev") == true)
     }
 
-    @Test func dockerProductImagePrewarmerSkipsBuildWhenImagePresent() async throws {
+    @Test func workerImageLabelDetectsMissingBinaries() async {
         let recorder = DockerCallRecorder()
         let executor: DockerCLIExecutor = { args, _, _ in
             await recorder.append(args)
+            if args.first == "image", args.contains("inspect"), args.contains("--format") {
+                return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
+            }
             return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
         }
-        try await DockerProductImagePrewarmer.ensureWebCrawlerImage(executor: executor)
-        #expect(await recorder.calls == [["image", "inspect", DockerProductImagePolicy.webCrawlerImage]])
+        let current = await DockerImageInspector.workerImageHasCurrentBinaries(executor: executor)
+        #expect(!current)
     }
 
-    @Test func dockerProductImagePrewarmerBuildsWhenImageMissing() async throws {
-        guard DerrickRepositoryRoot.locate() != nil else { return }
+    @Test func dockerProductImagePrewarmerSkipsBuildWhenImagePresent() async throws {
         let recorder = DockerCallRecorder()
         let executor: DockerCLIExecutor = { args, _, _ in
             await recorder.append(args)
-            if args.first == "image" {
-                return DockerCLIResult(exitCode: 1, stdout: Data(), stderr: Data())
-            }
-            if args.first == "build" {
-                return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
+            if let mocked = Self.mockWorkerImageInspect(args) {
+                return mocked
             }
             return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
         }
         try await DockerProductImagePrewarmer.ensureWebCrawlerImage(executor: executor)
         let calls = await recorder.calls
-        #expect(calls.count == 2)
-        #expect(calls[0] == ["image", "inspect", DockerProductImagePolicy.webCrawlerImage])
-        #expect(calls[1].first == "build")
-        #expect(calls[1].contains(DockerProductImagePolicy.webCrawlerImage))
-        #expect(calls[1].last?.hasSuffix("/\(DockerProductImagePolicy.webCrawlerBuildContextRelativePath)") == true)
+        #expect(calls.first == ["image", "inspect", DockerProductImagePolicy.workerImage])
+        #expect(calls.contains { $0.contains("--format") && $0.contains(where: { $0.contains(DockerWorkerRuntime.binariesLabelKey) }) })
+        #expect(calls.contains { $0.contains("{{.Id}}") })
+        #expect(!calls.contains { $0.first == "build" })
+    }
+
+    @Test func dockerProductImagePrewarmerBuildsWhenImageMissing() async throws {
+        guard DerrickRepositoryRoot.locate() != nil else { return }
+        let recorder = DockerCallRecorder()
+        let latch = ImageBuildLatch()
+        let executor = Self.missingUntilBuiltExecutor(recorder: recorder, latch: latch)
+        try await DockerProductImagePrewarmer.ensureWebCrawlerImage(executor: executor)
+        let calls = await recorder.calls
+        #expect(calls[0] == ["image", "inspect", DockerProductImagePolicy.workerImage])
+        #expect(calls.contains { $0.first == "build" && $0.contains(DockerProductImagePolicy.workerImage) })
+        #expect(calls.contains { $0.contains("{{.Id}}") })
+        #expect(calls.filter { $0.first == "build" }.count == 1)
     }
 
     @Test func crawlerImageBuildFailureMessageOmitsBuildkitDump() {
         let error = DockerProductImagePrewarmerError.buildFailed(
-            DockerProductImagePolicy.webCrawlerImage,
+            DockerProductImagePolicy.workerImage,
             "#0 building with \"default\" instance using docker driver"
         )
         let text = error.localizedDescription
         #expect(!text.contains("#0 building"))
-        #expect(text.lowercased().contains("web crawler"))
+        #expect(text.lowercased().contains("worker image"))
         #expect(text.lowercased().contains("disk"))
         #expect(error.compilerDiagnostic == nil)
     }
@@ -285,7 +384,7 @@ import WebCrawler
         error: Build failed
         """
         let error = DockerProductImagePrewarmerError.buildFailed(
-            DockerProductImagePolicy.webCrawlerImage,
+            DockerProductImagePolicy.workerImage,
             detail
         )
         #expect(error.compilerDiagnostic?.contains("CryptoKit") == true)
@@ -295,17 +394,12 @@ import WebCrawler
     @Test func crawlerImageBuildIsSingleFlight() async throws {
         guard DerrickRepositoryRoot.locate() != nil else { return }
         let recorder = DockerCallRecorder()
-        let executor: DockerCLIExecutor = { args, _, _ in
-            await recorder.append(args)
-            if args.first == "image" {
-                return DockerCLIResult(exitCode: 1, stdout: Data(), stderr: Data())
-            }
-            if args.first == "build" {
-                try await Task.sleep(for: .milliseconds(80))
-                return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
-            }
-            return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
-        }
+        let latch = ImageBuildLatch()
+        let executor = Self.missingUntilBuiltExecutor(
+            recorder: recorder,
+            latch: latch,
+            buildDelay: .milliseconds(80)
+        )
         let gate = WebCrawlerImageGate()
         try await withThrowingTaskGroup(of: Void.self) { group in
             group.addTask { try await gate.ensureReady(executor: executor) }
@@ -315,26 +409,18 @@ import WebCrawler
         }
         let calls = await recorder.calls
         #expect(calls.filter { $0.first == "build" }.count == 1)
-        #expect(calls.filter { $0.first == "image" }.count == 1)
+        #expect(calls.filter { $0 == ["image", "inspect", DockerProductImagePolicy.workerImage] }.count == 1)
     }
 
     @Test func crawlerImageBuildFailureAllowsRetry() async throws {
         guard DerrickRepositoryRoot.locate() != nil else { return }
         let recorder = DockerCallRecorder()
-        let executor: DockerCLIExecutor = { args, _, _ in
-            await recorder.append(args)
-            if args.first == "image" {
-                return DockerCLIResult(exitCode: 1, stdout: Data(), stderr: Data())
-            }
-            if args.first == "build" {
-                let builds = await recorder.calls.filter { $0.first == "build" }.count
-                if builds == 1 {
-                    return DockerCLIResult(exitCode: 1, stdout: Data(), stderr: Data("boom".utf8))
-                }
-                return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
-            }
-            return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
-        }
+        let latch = ImageBuildLatch()
+        let executor = Self.missingUntilBuiltExecutor(
+            recorder: recorder,
+            latch: latch,
+            failFirstBuild: true
+        )
         let gate = WebCrawlerImageGate()
         do {
             try await gate.ensureReady(executor: executor)
@@ -383,6 +469,9 @@ import WebCrawler
         let runner = FileExtractorDockerExecutor(
             executor: { arguments, _, _ in
                 await recorder.append(arguments)
+                if let mocked = Self.mockWorkerImageInspect(arguments) {
+                    return mocked
+                }
                 return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
             },
             queue: DerrickDockerRunQueue(maxConcurrentContainers: 1)
@@ -419,11 +508,17 @@ import WebCrawler
                 timeoutSeconds: 5
             )
             Issue.record("expected missing extractor image")
+        } catch is DockerProductImagePrewarmerError {
+            // Image is missing; prewarmer tries a rebuild and that mock also fails.
+        } catch is DockerImageDigestError {
+            // Pin check after a failed inspect.
         } catch let error as FileExtractorDockerExecutorError {
             #expect(error == .imageUnavailable(FileExtractorDockerExecutor.image))
         }
         let calls = await recorder.calls
-        #expect(calls == [["image", "inspect", FileExtractorDockerExecutor.image]])
+        #expect(calls.contains { $0.first == "image" && $0.contains("inspect") })
+        #expect(!calls.contains { $0.first == "create" })
+        #expect(!calls.contains { $0.first == "start" })
     }
 
     @Test func orphanSweeperRemovesLabeledAndPrefixedContainers() async throws {
@@ -825,9 +920,9 @@ import WebCrawler
         #expect(results?.first?["json"] == nil)
     }
 
-    @Test func pythonGuestRuntimeUsesPinnedImage() {
-        #expect(DerrickGuestRuntime.pythonGuestDockerImage == "python:3.14.7")
-        #expect(PythonGuestDockerExecutor.containerPrefix == "derrick-guest-runtime")
+    @Test func goGuestRuntimeUsesWorkerImage() {
+        #expect(DerrickGuestRuntime.guestDockerImage == DockerWorkerRuntime.image)
+        #expect(GoGuestDockerExecutor.containerPrefix == "derrick-guest-runtime")
         #expect(DerrickDockerRunQueue.guest.maxConcurrentContainers == 1)
         #expect(DerrickDockerRunQueue.crawler.maxConcurrentContainers == 2)
         #expect(DerrickDockerRunQueue.extractor.maxConcurrentContainers == 1)
@@ -847,7 +942,7 @@ import WebCrawler
 
     @Test func oneshotEnsurePulledImageSkipsPullWhenImageExists() async throws {
         let recorder = DockerCallRecorder()
-        try await OneshotDockerContainer.ensurePulledImage("python:3.14.7") { arguments, _, _ in
+        try await OneshotDockerContainer.ensurePulledImage(DockerWorkerRuntime.image) { arguments, _, _ in
             await recorder.append(arguments)
             return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
         }
@@ -858,7 +953,7 @@ import WebCrawler
 
     @Test func oneshotEnsurePulledImagePullsWhenMissing() async throws {
         let recorder = DockerCallRecorder()
-        try await OneshotDockerContainer.ensurePulledImage("python:3.14.7") { arguments, _, _ in
+        try await OneshotDockerContainer.ensurePulledImage(DockerWorkerRuntime.image) { arguments, _, _ in
             await recorder.append(arguments)
             if arguments.first == "image" {
                 return DockerCLIResult(exitCode: 1, stdout: Data(), stderr: Data())
@@ -867,7 +962,7 @@ import WebCrawler
         }
         let calls = await recorder.calls
         #expect(calls.contains { $0.starts(with: ["image", "inspect"]) })
-        #expect(calls.contains { $0.first == "pull" && $0.contains("python:3.14.7") })
+        #expect(calls.contains { $0.first == "pull" && $0.contains(DockerWorkerRuntime.image) })
     }
 
     @Test func dockerRunQueueSerializesWhenMaxIsOne() async throws {
@@ -915,7 +1010,7 @@ import WebCrawler
                     return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
                 },
                 prefix: "derrick-guest-runtime",
-                createArguments: { name in ["create", "--name", name, "python:3.14.7"] },
+                createArguments: { name in ["create", "--name", name, DockerWorkerRuntime.image] },
                 createStep: "create guest runtime container",
                 startStep: "start guest runtime container",
                 body: { _ in
@@ -931,40 +1026,35 @@ import WebCrawler
         }
     }
 
-    @Test func pythonSourceVerifierRejectsNetworkAndDependencies() {
-        let findings = PythonScriptVerifier.validate(
-            source: "import sys\nimport requests",
+    @Test func goSourceVerifierRejectsNetworkAndDependencies() {
+        let findings = GoScriptVerifier.validate(
+            source: "package main\nimport \"net/http\"",
             dependencies: ["example": "1.0.0"]
         )
-        #expect(findings.contains("Direct network access is not allowed; emit http.request envelopes."))
-        #expect(findings.contains("Guest plugin dependencies are not supported; use the standard library."))
+        #expect(findings.contains("Go guest must not import \"net/http\"."))
+        #expect(findings.contains("Guest script dependencies are not supported."))
     }
 
-    @Test func pythonSourceVerifierRequiresStdin() {
-        let findings = PythonScriptVerifier.validate(source: "print('[]')")
-        #expect(findings.contains("Python source must read its JSON event from standard input."))
+    @Test func goSourceVerifierRequiresPackageMain() {
+        let findings = GoScriptVerifier.validate(source: "package plugin")
+        #expect(findings.contains("Go guest source must declare package main."))
     }
 
-    @Test func pythonExecutorUsesReadOnlyOfflineContainer() async throws {
+    @Test func goExecutorUsesReadOnlyOfflineContainer() async throws {
         let recorder = DockerCallRecorder()
-        let runner = PythonGuestDockerExecutor(
-            image: "python:3.14.7",
+        let runner = GoGuestDockerExecutor(
+            image: DockerWorkerRuntime.image,
             executor: { arguments, _, _ in
                 await recorder.append(arguments)
-                if arguments.contains("/tmp/guest.py"),
-                   !arguments.contains("cat") {
-                    return DockerCLIResult(
-                        exitCode: 0,
-                        stdout: Data(#"[{"verb":"result.emit","summary":"ok"}]"#.utf8),
-                        stderr: Data()
-                    )
+                if let mocked = Self.mockGuestDocker(arguments) {
+                    return mocked
                 }
                 return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
             },
             queue: DerrickDockerRunQueue(maxConcurrentContainers: 1)
         )
         _ = try await runner.runSource(
-            source: "import json, sys\njson.dump([], sys.stdout)",
+            source: Self.dummyGoScript,
             input: Data(#"{"kind":"script"}"#.utf8)
         )
 
@@ -975,15 +1065,17 @@ import WebCrawler
         #expect(create.contains("--read-only"))
         #expect(create.contains("--label"))
         #expect(create.contains(DerrickDockerRuntimeIdentity.labelAssignment))
-        let exec = calls.first(where: { $0.contains("python3") }) ?? []
-        #expect(exec.contains("/tmp/guest.py"))
+        #expect(calls.contains { $0.contains(DockerWorkerRuntime.guestWriteSourceShell) })
+        #expect(calls.contains { $0.contains(DockerWorkerRuntime.guestCompileShell) })
+        let exec = calls.first(where: { $0.contains(DockerWorkerRuntime.guestBinaryPath) }) ?? []
+        #expect(exec.contains(DockerWorkerRuntime.guestBinaryPath))
         #expect(calls.contains { $0.first == "rm" && $0.contains("-f") })
     }
 
-    @Test func pythonGuestDockerCommandsPassXPCValidation() async throws {
+    @Test func goGuestDockerCommandsPassXPCValidation() async throws {
         let recorder = DockerCallRecorder()
-        let runner = PythonGuestDockerExecutor(
-            image: "python:3.14.7",
+        let runner = GoGuestDockerExecutor(
+            image: DockerWorkerRuntime.image,
             executor: { arguments, _, _ in
                 await recorder.append(arguments)
                 if let error = DockerRunRequestValidator.validate(
@@ -995,26 +1087,22 @@ import WebCrawler
                         stderr: Data(error.launchErrorMessage.utf8)
                     )
                 }
-                if arguments.contains("/tmp/guest.py"),
-                   !arguments.contains("cat") {
-                    return DockerCLIResult(
-                        exitCode: 0,
-                        stdout: Data(#"[{"verb":"result.emit","summary":"ok"}]"#.utf8),
-                        stderr: Data()
-                    )
+                if let mocked = Self.mockGuestDocker(arguments) {
+                    return mocked
                 }
                 return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
             },
             queue: DerrickDockerRunQueue(maxConcurrentContainers: 1)
         )
         let result = try await runner.runSource(
-            source: "import json, sys\njson.dump([], sys.stdout)",
+            source: Self.dummyGoScript,
             input: Data(#"{"kind":"script"}"#.utf8)
         )
         #expect(result.exitCode == 0)
         let calls = await recorder.calls
-        #expect(calls.contains { $0.contains("sh") && $0.contains("cat > /tmp/guest.py") })
-        #expect(calls.contains { $0.contains("python3") && $0.contains("/tmp/guest.py") })
+        #expect(calls.contains { $0.contains(DockerWorkerRuntime.guestWriteSourceShell) })
+        #expect(calls.contains { $0.contains(DockerWorkerRuntime.guestCompileShell) })
+        #expect(calls.contains { $0.contains(DockerWorkerRuntime.guestBinaryPath) })
     }
 
     @Test func leftoverSwiftRuntimePrefixIsStillSwept() {
@@ -1022,15 +1110,15 @@ import WebCrawler
         #expect(GuestRuntimeLimits.maxTimeoutSeconds == 300)
     }
 
-    @Test func pythonScriptCanReturnHTMLResult() async throws {
+    @Test func goScriptCanReturnHTMLResult() async throws {
         let resultText = try await ScriptExecutionRuntime.run(
             arguments: [
                 "description": .string("render a safe card"),
                 "reason": .string("manual HTML output check"),
-                "script": .string(Self.dummyPythonScript)
+                "script": .string(Self.dummyGoScript)
             ],
             stdinExecutor: { arguments, _, _ in
-                if arguments.contains("python3"), arguments.contains("/tmp/guest.py") {
+                if Self.isGuestBinaryExec(arguments) {
                     return DockerCLIResult(
                         exitCode: 0,
                         stdout: Data(
@@ -1039,6 +1127,9 @@ import WebCrawler
                         stderr: Data()
                     )
                 }
+                if let mocked = Self.mockGuestDocker(arguments) {
+                    return mocked
+                }
                 return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
             },
             reviewer: StubReviewer(
@@ -1058,13 +1149,13 @@ import WebCrawler
         #expect(result.output?.value == "<p><strong>Safe</strong></p>")
     }
 
-    @Test func scriptExecRejectsSwiftLanguage() async throws {
+    @Test func scriptExecRejectsUnsupportedLanguage() async throws {
         let resultText = try await ScriptExecutionRuntime.run(
             arguments: [
-                "description": .string("legacy swift"),
+                "description": .string("legacy python"),
                 "reason": .string("should be blocked"),
-                "script": .string(Self.dummyPythonScript),
-                "language": .string("swift")
+                "script": .string(Self.dummyGoScript),
+                "language": .string("python")
             ],
             stdinExecutor: Self.dummyStdin,
             reviewer: nil,
@@ -1074,10 +1165,10 @@ import WebCrawler
         let result = try #require(ToolExecutionOutcome.decode(from: resultText))
         #expect(result.status == .blocked)
         #expect(result.stage == .validation)
-        #expect(resultText.contains("only runs Python"))
+        #expect(resultText.contains("only runs Go"))
     }
 
-    @Test func pythonScriptToolBlocksFilesystemAccess() async throws {
+    @Test func goScriptToolBlocksFilesystemAccess() async throws {
         let bridge = try await MCPLocalBridge.make { server in
             await server.registerScriptExecutionTool(
                 stdinExecutor: Self.dummyStdin,
@@ -1098,7 +1189,7 @@ import WebCrawler
             arguments: [
                 "description": .string("attempt write"),
                 "reason": .string("test"),
-                "script": .string("import sys\n_ = sys.stdin.read()\nopen('/tmp/a','w')")
+                "script": .string("package main\nimport \"os\"\nfunc main() { _, _ = os.Open(\"/tmp/a\") }")
             ]
         )
 
@@ -1108,18 +1199,18 @@ import WebCrawler
 
     @Test func leftoverSwiftGuestImageIsTreatedAsStaleHygieneTag() {
         #expect(DerrickGuestRuntime.swiftPluginDockerImage.contains("swift"))
-        #expect(DerrickGuestRuntime.pythonGuestDockerImage == "python:3.14.7")
+        #expect(DerrickGuestRuntime.guestDockerImage == DockerWorkerRuntime.image)
     }
 
-    @Test func guestPluginRunnerRunsPythonRelease() async throws {
+    @Test func guestPluginRunnerRunsGoRelease() async throws {
         let recorder = DockerCallRecorder()
         let release = PluginFactoryRelease(
             pluginID: "slack-connection",
             version: "1.0.0",
             manifestJSON: "{}",
-            runtimeJSON: #"{"language":"python","entrypoint":"./app.derrick/plugin.py"}"#,
-            guestSource: "import json, sys\njson.dump([{\"verb\":\"result.emit\",\"summary\":\"ok\"}], sys.stdout)",
-            compiledArtifact: Data(),
+            runtimeJSON: #"{"language":"go","entrypoint":"./app.derrick/plugin.go"}"#,
+            guestSource: Self.dummyGoScript,
+            compiledArtifact: Self.dummyCompiledGuest,
             skillFiles: [:],
             contentHash: try PluginContentHash(hex: String(repeating: "c", count: 64)),
             reviewSummary: "ok"
@@ -1129,21 +1220,23 @@ import WebCrawler
             input: Data(#"{"kind":"manual"}"#.utf8),
             dockerExecutor: { arguments, _, _ in
                 await recorder.append(arguments)
-                if arguments.contains("/tmp/guest.py"),
-                   !arguments.contains("cat") {
+                if Self.isGuestBinaryExec(arguments) {
                     return DockerCLIResult(
                         exitCode: 0,
                         stdout: Data(#"[{"verb":"result.emit","summary":"ok"}]"#.utf8),
                         stderr: Data()
                     )
                 }
+                if let mocked = Self.mockGuestDocker(arguments) {
+                    return mocked
+                }
                 return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
             }
         )
         #expect(result.exitCode == 0)
         #expect(String(decoding: result.stdout, as: UTF8.self).contains("result.emit"))
         let calls = await recorder.calls
-        #expect(calls.contains { $0.contains("python3") })
+        #expect(calls.contains { $0.contains(DockerWorkerRuntime.guestBinaryPath) })
         #expect(!calls.contains { $0.contains("swift") })
     }
 
@@ -1274,12 +1367,12 @@ import WebCrawler
         #expect(hops == PluginContract.maxPluginInvokeHops)
     }
 
-    @Test func pythonGuestContainerArgumentsStayNetworkIsolated() {
+    @Test func goGuestContainerArgumentsStayNetworkIsolated() {
         let name = "derrick-guest-runtime-test"
         let args = [
             "create", "--network", "none", "--name", name, "--read-only",
             "--tmpfs", "/tmp:rw,exec,nosuid,size=128m",
-            DerrickGuestRuntime.pythonGuestDockerImage, "/bin/sleep", "infinity",
+            DerrickGuestRuntime.guestDockerImage, "/bin/sleep", "infinity",
         ]
         #expect(args.contains("--name"))
         #expect(args.contains(name))
@@ -1301,7 +1394,7 @@ import WebCrawler
                 "mode": .string("write"),
                 "description": .string("create report file"),
                 "reason": .string("user asked for file output"),
-                "script": .string(Self.dummyPythonScript),
+                "script": .string(Self.dummyGoScript),
                 "expected_effects": .array([.string("write /tmp/report.txt")]),
                 "allow_network": .bool(true)
             ]
@@ -1332,7 +1425,7 @@ import WebCrawler
                 "mode": .string("readonly"),
                 "description": .string("inspect csv"),
                 "reason": .string("analyze user-provided data"),
-                "script": .string(Self.dummyPythonScript),
+                "script": .string(Self.dummyGoScript),
                 "user_prompt": .string("summarize this csv"),
                 "allow_network": .bool(true)
             ]
@@ -1448,7 +1541,7 @@ import WebCrawler
                 "mode": .string("readonly"),
                 "description": .string("fetch page"),
                 "reason": .string("test"),
-                "script": .string(Self.dummyPythonScript),
+                "script": .string(Self.dummyGoScript),
                 "allow_network": .bool(true)
             ]
         )
diff --git a/packages/MCPServer/Tests/MCPServerTests/PythonPluginFactoryDockerExecutorTests.swift b/packages/MCPServer/Tests/MCPServerTests/PythonPluginFactoryDockerExecutorTests.swift
deleted file mode 100644
index b95215d0..00000000
--- a/packages/MCPServer/Tests/MCPServerTests/PythonPluginFactoryDockerExecutorTests.swift
+++ /dev/null
@@ -1,41 +0,0 @@
-import Foundation
-import MCPServer
-import Plugin
-import Testing
-import Structure
-
-@Suite struct PythonPluginFactoryDockerExecutorTests {
-    @Test func packagesAndRunsPythonSource() async throws {
-        let recorder = DockerCallRecorder()
-        let runner = PythonPluginFactoryDockerExecutor(
-            image: "python:3.14.7",
-            executor: { arguments, _, _ in
-                await recorder.append(arguments)
-                if arguments.contains("/tmp/guest.py"),
-                   !arguments.contains("cat") {
-                    return DockerCLIResult(
-                        exitCode: 0,
-                        stdout: Data(#"[{"verb":"result.emit","summary":"ok"}]"#.utf8),
-                        stderr: Data()
-                    )
-                }
-                return DockerCLIResult(exitCode: 0, stdout: Data(), stderr: Data())
-            }
-        )
-        let draft = try await runner.runGuestSource(
-            source: "import json, sys\njson.dump([], sys.stdout)",
-            input: Data(#"{"kind":"manual"}"#.utf8)
-        )
-        #expect(draft.exitCode == 0)
-        let packaged = try await runner.packageGuestSource(
-            source: "import json, sys\njson.dump([], sys.stdout)"
-        )
-        let released = try await runner.runPackagedArtifact(
-            packaged,
-            input: Data(#"{"kind":"manual"}"#.utf8)
-        )
-        #expect(released.exitCode == 0)
-        let calls = await recorder.calls
-        #expect(calls.contains { $0.contains("python3") && $0.contains("/tmp/guest.py") })
-    }
-}
diff --git a/packages/Plugin/Sources/Plugin/Factory/GuestGoSourceValidator.swift b/packages/Plugin/Sources/Plugin/Factory/GuestGoSourceValidator.swift
new file mode 100644
index 00000000..e4bd5293
--- /dev/null
+++ b/packages/Plugin/Sources/Plugin/Factory/GuestGoSourceValidator.swift
@@ -0,0 +1,35 @@
+import Foundation
+import Structure
+
+public enum GuestGoSourceValidator: Sendable {
+    private static let forbiddenImports = [
+        "\"net/http\"",
+        "\"net\"",
+        "\"os/exec\"",
+        "\"crypto/tls\"",
+    ]
+
+    private static let forbiddenCalls = [
+        "os.Open",
+        "os.ReadFile",
+        "os.WriteFile",
+        "exec.Command",
+        "http.Get",
+        "http.Post",
+        "http.Client",
+    ]
+
+    public static func validate(source: String) -> [String] {
+        var findings: [String] = []
+        for token in forbiddenImports where source.contains(token) {
+            findings.append("Go guest must not import \(token).")
+        }
+        for token in forbiddenCalls where source.contains(token) {
+            findings.append("Go guest must not call \(token).")
+        }
+        if !source.contains("package main") {
+            findings.append("Go guest source must declare package main.")
+        }
+        return findings
+    }
+}
diff --git a/packages/Plugin/Sources/Plugin/Factory/GuestPythonSourceValidator.swift b/packages/Plugin/Sources/Plugin/Factory/GuestPythonSourceValidator.swift
deleted file mode 100644
index 2bc56739..00000000
--- a/packages/Plugin/Sources/Plugin/Factory/GuestPythonSourceValidator.swift
+++ /dev/null
@@ -1,44 +0,0 @@
-import Foundation
-import Structure
-
-/// Conservative source checks for Python guest plugins and factory drafts.
-public enum GuestPythonSourceValidator: Sendable {
-    public static func validate(
-        source: String,
-        dependencies: [String: String] = [:]
-    ) -> [String] {
-        var findings: [String] = []
-        let trimmed = source.trimmingCharacters(in: .whitespacesAndNewlines)
-
-        if trimmed.isEmpty {
-            findings.append("Python source is empty.")
-        }
-
-        let forbiddenTokens: [(String, String)] = [
-            ("import socket", "Direct socket access is not allowed; emit http.request envelopes."),
-            ("from socket", "Direct socket access is not allowed; emit http.request envelopes."),
-            ("import urllib", "Direct network access is not allowed; emit http.request envelopes."),
-            ("from urllib", "Direct network access is not allowed; emit http.request envelopes."),
-            ("import requests", "Direct network access is not allowed; emit http.request envelopes."),
-            ("import httpx", "Direct network access is not allowed; emit http.request envelopes."),
-            ("import subprocess", "Process execution is not allowed."),
-            ("os.system(", "Process execution is not allowed."),
-            ("os.popen(", "Process execution is not allowed."),
-            ("open(", "Filesystem access is not allowed in guest plugins."),
-        ]
-        for (token, message) in forbiddenTokens where source.contains(token) {
-            findings.append(message)
-        }
-
-        let readsStdin = source.contains("sys.stdin")
-            || source.contains("input(")
-            || source.contains("stdin.read")
-        if !readsStdin {
-            findings.append("Python source must read its JSON event from standard input.")
-        }
-        if !dependencies.isEmpty {
-            findings.append("Guest plugin dependencies are not supported; use the standard library.")
-        }
-        return findings
-    }
-}
diff --git a/packages/Plugin/Sources/Plugin/Factory/PluginFactoryImplementation.swift b/packages/Plugin/Sources/Plugin/Factory/PluginFactoryImplementation.swift
index b5883093..046e54e2 100644
--- a/packages/Plugin/Sources/Plugin/Factory/PluginFactoryImplementation.swift
+++ b/packages/Plugin/Sources/Plugin/Factory/PluginFactoryImplementation.swift
@@ -76,12 +76,8 @@ public struct PluginFactorySession: Sendable {
                 "Fix every item below in your next JSON draft response:",
             ]
             parts.append(contentsOf: findings.map { "- \($0)" })
-            parts.append(
-                """
-                Connector test_input_json must use a hops array replayed by the factory. Match each http.request \
-                request_id to an http_results fixture. Declare the same ops in messaging_ops and params.messaging_op.
-                """
-            )
+            parts.append(ScriptExecContractPrompts.pluginFactoryBuilderGuide())
+            parts.append(ConnectorContractPrompts.builderGuide(forUserGoal: userGoal))
             return parts.joined(separator: "\n")
         case .reviewRejected(let summary, let findings):
             var parts = [
@@ -92,23 +88,8 @@ public struct PluginFactorySession: Sendable {
                 parts.append("Findings:")
                 parts.append(contentsOf: findings.map { "- \($0)" })
             }
-            parts.append(
-                """
-                Connector protocol (do not add rules):
-                \(ConnectorContractPrompts.reviewerGuide(forUserGoal: userGoal))
-                """
-            )
-            parts.append(
-                """
-                Before returning the next draft, update test_input_json to a hops array replayed by the factory:
-                {"hops":[{"kind":"message_in_room","params":{"messaging_op":"send_message",...}},\
-                {"kind":"http_results","http_results":[{"request_id":"...","status":200,"body":"..."}],\
-                "params":{...}}]}
-                Include http_results fixtures for every messaging_op you implement. Match request_id values \
-                in fixtures to the http.request envelopes your python_source emits. De-duplicate http_results \
-                by request_id using stable sorting — do not overwrite duplicates by response order.
-                """
-            )
+            parts.append(ScriptExecContractPrompts.pluginFactoryReviewerGuide())
+            parts.append(ConnectorContractPrompts.reviewerGuide(forUserGoal: userGoal))
             return parts.joined(separator: "\n")
         default:
             return error.localizedDescription
@@ -259,10 +240,14 @@ public struct PluginFactory: Sendable {
         }
 
         let runtimeJSON = try runtimeJSON(for: manifest)
+        let guestPath = PluginFactoryRuntime.guestSourcePackagePath(
+            runtimeJSON: runtimeJSON,
+            manifestJSON: draft.manifestJSON
+        )
         var files: [String: Data] = [
             "plugin.json": Data(draft.manifestJSON.utf8),
             "app.derrick/runtime.json": Data(runtimeJSON.utf8),
-            "app.derrick/plugin.py": Data(draft.guestSource.utf8),
+            guestPath: Data(draft.guestSource.utf8),
             "app.derrick/plugin": artifact,
         ]
         for (path, body) in draft.skillFiles {
@@ -293,9 +278,9 @@ public struct PluginFactory: Sendable {
         do {
             let manifest = try AgentPluginManifest.decode(data)
             guard let entrypoint = manifest.derrick?.entrypoint,
-                  entrypoint.hasSuffix(".py") else {
+                  entrypoint.hasSuffix(".go") else {
                 throw PluginFactoryError.invalidManifest(
-                    "extensions.app.derrick.entrypoint must point to a Python file."
+                    "extensions.app.derrick.entrypoint must point to a Go file."
                 )
             }
             guard !["create-plugin", "edit-plugin"].contains(manifest.name.rawValue) else {
@@ -323,7 +308,7 @@ public struct PluginFactory: Sendable {
     }
 
     private func validateSource(_ source: String) throws {
-        let findings = GuestPythonSourceValidator.validate(source: source)
+        let findings = GuestGoSourceValidator.validate(source: source)
         if let first = findings.first {
             throw PluginFactoryError.invalidSource(first)
         }
@@ -331,10 +316,10 @@ public struct PluginFactory: Sendable {
 
     private func runtimeJSON(for manifest: AgentPluginManifest) throws -> String {
         guard let entrypoint = manifest.derrick?.entrypoint else {
-            throw PluginFactoryError.invalidManifest("A Python entrypoint is required.")
+            throw PluginFactoryError.invalidManifest("A Go entrypoint is required.")
         }
         let object: [String: String] = [
-            "language": "python",
+            "language": "go",
             "entrypoint": entrypoint,
         ]
         let data = try JSONSerialization.data(withJSONObject: object, options: [.sortedKeys])
diff --git a/packages/Plugin/Sources/Plugin/Factory/PluginFactoryRuntime.swift b/packages/Plugin/Sources/Plugin/Factory/PluginFactoryRuntime.swift
index b5e45a75..2583c1e7 100644
--- a/packages/Plugin/Sources/Plugin/Factory/PluginFactoryRuntime.swift
+++ b/packages/Plugin/Sources/Plugin/Factory/PluginFactoryRuntime.swift
@@ -2,6 +2,7 @@ import Foundation
 import Structure
 
 public extension PluginFactoryRelease {
-    /// All approved releases run as Python guests.
-    var guestLanguage: PluginGuestLanguage { .python }
+    var guestLanguage: PluginGuestLanguage {
+        PluginFactoryRuntime.decode(from: runtimeJSON)?.language ?? .go
+    }
 }
diff --git a/packages/Plugin/Tests/PluginTests/PluginFactoryTests.swift b/packages/Plugin/Tests/PluginTests/PluginFactoryTests.swift
index e84fea76..5fa5adec 100644
--- a/packages/Plugin/Tests/PluginTests/PluginFactoryTests.swift
+++ b/packages/Plugin/Tests/PluginTests/PluginFactoryTests.swift
@@ -4,35 +4,79 @@ import Testing
 @testable import Plugin
 
 @Suite struct PluginFactoryTests {
-    private func guestPythonSource(emit: String = #"[]"#) -> String {
+    private func guestGoSource(summary: String = "ok") -> String {
         """
-        import json, sys
-        _ = json.load(sys.stdin)
-        json.dump(\(emit), sys.stdout)
+        package main
+
+        import (
+            "encoding/json"
+            "os"
+        )
+
+        func main() {
+            var event map[string]any
+            _ = json.NewDecoder(os.Stdin).Decode(&event)
+            enc := json.NewEncoder(os.Stdout)
+            enc.SetEscapeHTML(false)
+            _ = enc.Encode([]map[string]any{{"verb": "result.emit", "summary": "\(summary)"}})
+        }
         """
     }
 
-    @Test func guestLanguageIsAlwaysPython() {
+    @Test func releaseVerifiesWithEntrypointGuestPath() throws {
+        let runtimeJSON = #"{"entrypoint":"./app.derrick/plugin.go","language":"go"}"#
+        let manifestJSON = """
+        {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connector-1","version":"1.0.0",\
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector"}}}
+        """
+        let guestSource = "package main\n"
+        let artifact = Data("binary".utf8)
+        let guestPath = PluginFactoryRuntime.guestSourcePackagePath(
+            runtimeJSON: runtimeJSON,
+            manifestJSON: manifestJSON
+        )
+        #expect(guestPath == "app.derrick/plugin.go")
+        let files: [String: Data] = [
+            "plugin.json": Data(manifestJSON.utf8),
+            "app.derrick/runtime.json": Data(runtimeJSON.utf8),
+            guestPath: Data(guestSource.utf8),
+            "app.derrick/plugin": artifact,
+        ]
+        let release = PluginFactoryRelease(
+            pluginID: "slack-connector-1",
+            version: "1.0.0",
+            manifestJSON: manifestJSON,
+            runtimeJSON: runtimeJSON,
+            guestSource: guestSource,
+            compiledArtifact: artifact,
+            skillFiles: [:],
+            contentHash: PluginContentHash.hash(files: files),
+            reviewSummary: "ok"
+        )
+        #expect(release.verifyIntegrity())
+    }
+
+    @Test func guestLanguageIsGoFromRuntimeJSON() {
         let release = PluginFactoryRelease(
             pluginID: "slack-connection",
             version: "1.0.0",
             manifestJSON: "{}",
-            runtimeJSON: #"{"language":"python","entrypoint":"./app.derrick/plugin.py"}"#,
-            guestSource: guestPythonSource(),
+            runtimeJSON: #"{"language":"go","entrypoint":"./app.derrick/plugin.go"}"#,
+            guestSource: guestGoSource(),
             compiledArtifact: Data(),
             skillFiles: [:],
             contentHash: try! PluginContentHash(hex: String(repeating: "b", count: 64)),
             reviewSummary: "ok"
         )
-        #expect(release.guestLanguage == .python)
+        #expect(release.guestLanguage == .go)
     }
 
-    @Test func pluginFactoryRuntimeDecodesPythonEntrypoint() {
+    @Test func pluginFactoryRuntimeDecodesGoEntrypoint() {
         let runtime = PluginFactoryRuntime.decode(
-            from: #"{"language":"python","entrypoint":"./app.derrick/plugin.py"}"#
+            from: #"{"language":"go","entrypoint":"./app.derrick/plugin.go"}"#
         )
-        #expect(runtime?.language == .python)
-        #expect(runtime?.entrypoint.hasSuffix(".py") == true)
+        #expect(runtime?.language == .go)
+        #expect(runtime?.entrypoint.hasSuffix(".go") == true)
     }
 
     @Test func envelopeDecoderRejectsNestedResultAliases() {
@@ -47,7 +91,7 @@ import Testing
         let reviewer = RecordingFactoryReviewer(result: PluginFactoryReview(approved: true, summary: "safe"))
         let draft = PluginFactoryDraft(
             manifestJSON: manifestJSON(),
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             testInput: Data(#"{"kind":"manual"}"#.utf8),
             skillFiles: ["skills/weather/SKILL.md": "# Weather\n\nReturn weather."]
         )
@@ -60,12 +104,12 @@ import Testing
 
         #expect(release.pluginID == "weather-tool")
         #expect(release.version == "1.2.3")
-        #expect(release.runtimeJSON.contains("\"language\":\"python\""))
-        #expect(release.runtimeJSON.contains("plugin.py"))
+        #expect(release.runtimeJSON.contains("\"language\":\"go\""))
+        #expect(release.runtimeJSON.contains("plugin.go"))
         #expect(!release.contentHash.rawValue.isEmpty)
         #expect(release.verifyIntegrity())
         var tampered = release.packageFiles()
-        tampered["app.derrick/plugin.py"] = Data("changed".utf8)
+        tampered["app.derrick/plugin.go"] = Data("changed".utf8)
         #expect(!PluginFactoryRelease.verifyIntegrity(files: tampered, expected: release.contentHash))
         #expect(await executor.draftRunCount == 1)
         #expect(await executor.packageCount == 1)
@@ -83,7 +127,7 @@ import Testing
             _ = try await PluginFactory().build(
                 draft: PluginFactoryDraft(
                     manifestJSON: manifestJSON(),
-                    guestSource: guestPythonSource()
+                    guestSource: guestGoSource()
                 ),
                 executor: executor,
                 reviewer: reviewer
@@ -110,9 +154,17 @@ import Testing
                 draft: PluginFactoryDraft(
                     manifestJSON: manifestJSON(),
                     guestSource: """
-                    import json, sys
-                    _ = json.load(sys.stdin)
-                    print("not a plugin envelope")
+                    package main
+
+                    import (
+                        "encoding/json"
+                        "os"
+                    )
+
+                    func main() {
+                        _ = json.NewDecoder(os.Stdin).Decode(&map[string]any{})
+                        os.Stdout.WriteString("not a plugin envelope")
+                    }
                     """,
                     testInput: Data(#"{"kind":"manual"}"#.utf8)
                 ),
@@ -121,10 +173,7 @@ import Testing
             )
             Issue.record("Expected invalid output")
         } catch let error as PluginFactoryError {
-            #expect(
-                error.localizedDescription.contains("invalid plugin output")
-                    || error.localizedDescription.contains("Python draft test failed")
-            )
+            #expect(error.localizedDescription.contains("invalid plugin output"))
             #expect(await reviewer.callCount == 0)
         }
     }
@@ -222,7 +271,7 @@ import Testing
     @Test func reservedPluginIDsCannotBeCreated() async {
         let draft = PluginFactoryDraft(
             manifestJSON: manifestJSON().replacingOccurrences(of: "weather-tool", with: "create-plugin"),
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
         )
         do {
             _ = try await PluginFactory().build(
@@ -242,13 +291,13 @@ import Testing
 
     @Test func missingSchemaIsRejectedAtTheFactoryBoundary() async {
         let manifest = """
-        {"name":"weather-tool","version":"1.0.0","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py"}}}
+        {"name":"weather-tool","version":"1.0.0","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go"}}}
         """
         do {
             _ = try await PluginFactory().build(
                 draft: PluginFactoryDraft(
                     manifestJSON: manifest,
-                    guestSource: guestPythonSource()
+                    guestSource: guestGoSource()
                 ),
                 executor: RecordingFactoryExecutor(),
                 reviewer: RecordingFactoryReviewer(
@@ -268,12 +317,12 @@ import Testing
             pluginID: "weather-tool",
             version: "1.0.0",
             description: "Weather summaries.",
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
         )
         let draft = try response.draft()
         let manifest = try AgentPluginManifest.decode(Data(draft.manifestJSON.utf8))
         #expect(manifest.schema == PluginContract.agentPluginSchema)
-        #expect(manifest.derrick?.entrypoint == "./app.derrick/plugin.py")
+        #expect(manifest.derrick?.entrypoint == "./app.derrick/plugin.go")
     }
 
     @Test func builderNormalizesUnderscorePluginIDAndWritesSecretLabels() throws {
@@ -281,7 +330,7 @@ import Testing
             pluginID: "slack_connection",
             version: "1.0.0",
             description: "Slack send and receive.",
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             secrets: [
                 try PluginSecretField(id: "username", label: "Slack username", kind: .username),
                 try PluginSecretField(id: "password", label: "Slack password", kind: .password),
@@ -300,7 +349,7 @@ import Testing
             pluginID: "slack-connection",
             version: "1.0.0",
             description: "Slack send and receive.",
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             role: .connector,
             messagingOps: ["send_message"]
         )
@@ -319,7 +368,7 @@ import Testing
             pluginID: "slack-connection",
             version: "1.0.0",
             description: "Slack full sync.",
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             role: .connector
         )
         let draft = try response.draft()
@@ -329,7 +378,7 @@ import Testing
     @Test func connectorTestScriptRequiresHopsAndFixtures() throws {
         let manifestJSON = """
         {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connection","version":"1.0.0",\
-        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
         """
         let manifest = try AgentPluginManifest.decode(Data(manifestJSON.utf8))
         #expect(throws: PluginFactoryError.self) {
@@ -337,7 +386,7 @@ import Testing
         }
         let draft = PluginFactoryDraft(
             manifestJSON: manifestJSON,
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             testInput: Data(
                 #"{"kind":"message_in_room","params":{"messaging_op":"send_message"}}"#.utf8
             ),
@@ -374,7 +423,7 @@ import Testing
     @Test func fullSyncTestScriptRequiresReplyThreadPollHop() throws {
         let manifestJSON = """
         {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connection","version":"1.0.0",\
-        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
         """
         let manifest = try AgentPluginManifest.decode(Data(manifestJSON.utf8))
         let channelOnly = Data(
@@ -391,7 +440,7 @@ import Testing
         )
         let missingReplies = PluginFactoryDraft(
             manifestJSON: manifestJSON,
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             testInput: channelOnly,
             userGoal: fullSyncGoal()
         )
@@ -401,7 +450,7 @@ import Testing
 
         let withReplies = PluginFactoryDraft(
             manifestJSON: manifestJSON,
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             testInput: Data(
                 """
                 {"hops":[
@@ -424,7 +473,7 @@ import Testing
     @Test func dualFixtureAllowsUnsortedHttpResultsLoop() throws {
         let manifestJSON = """
         {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connection","version":"1.0.0",\
-        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
         """
         let manifest = try AgentPluginManifest.decode(Data(manifestJSON.utf8))
         let testInput = Data(
@@ -446,17 +495,7 @@ import Testing
         )
         let draft = PluginFactoryDraft(
             manifestJSON: manifestJSON,
-            guestSource: """
-            import json, sys
-            event = json.load(sys.stdin)
-            for item in event.get("http_results") or []:
-                if item.get("request_id") == "send-1":
-                    body = json.loads(item.get("body") or "{}")
-                    if body.get("ok"):
-                        json.dump([{"verb":"result.emit","sent_message":{"vendor_message_id":"1.0","created_at":"1.0"}}], sys.stdout)
-                        sys.exit(0)
-            json.dump([{"verb":"result.emit","summary":"failed"}], sys.stdout)
-            """,
+            guestSource: connectorGuestGoSource(),
             testInput: testInput,
             userGoal: fullSyncGoal()
         )
@@ -519,7 +558,7 @@ import Testing
 
     @Test func missingRoleDefaultsToStandard() throws {
         let json = """
-        {"$schema":"\(PluginContract.agentPluginSchema)","name":"weather-tool","version":"1.0.0","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py"}}}
+        {"$schema":"\(PluginContract.agentPluginSchema)","name":"weather-tool","version":"1.0.0","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go"}}}
         """
         let manifest = try AgentPluginManifest.decode(Data(json.utf8))
         #expect(manifest.derrick?.role == .standard)
@@ -528,7 +567,7 @@ import Testing
 
     @Test func invalidRoleIsRejected() {
         let json = """
-        {"$schema":"\(PluginContract.agentPluginSchema)","name":"weather-tool","version":"1.0.0","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"slack"}}}
+        {"$schema":"\(PluginContract.agentPluginSchema)","name":"weather-tool","version":"1.0.0","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"slack"}}}
         """
         do {
             _ = try AgentPluginManifest.decode(Data(json.utf8))
@@ -555,7 +594,7 @@ import Testing
             pluginID: "weather-tool",
             version: "1.0.0",
             description: "Weather summaries.",
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             skillFiles: [
                 PluginFactorySkillFile(path: "SKILL.md", body: "Invalid layout.")
             ]
@@ -575,14 +614,14 @@ import Testing
     private func draft() -> PluginFactoryDraft {
         PluginFactoryDraft(
             manifestJSON: manifestJSON(),
-            guestSource: guestPythonSource(),
+            guestSource: guestGoSource(),
             testInput: Data(#"{"kind":"manual"}"#.utf8)
         )
     }
 
     private func manifestJSON() -> String {
         """
-        {"$schema":"\(PluginContract.agentPluginSchema)","name":"weather-tool","version":"1.2.3","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py"}}}
+        {"$schema":"\(PluginContract.agentPluginSchema)","name":"weather-tool","version":"1.2.3","extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go"}}}
         """
     }
 }
@@ -615,24 +654,51 @@ private func validConnectorTestInput() -> Data {
 private func connectorDraft(testInput: Data) -> PluginFactoryDraft {
     let manifestJSON = """
     {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connection","version":"1.0.0",\
-    "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","auth_scheme":"bot_token","secrets":[{"id":"bot_token","label":"Bot Token","kind":"token"}],"messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
+    "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","auth_scheme":"bot_token","secrets":[{"id":"bot_token","label":"Bot Token","kind":"token"}],"messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
     """
     return PluginFactoryDraft(
         manifestJSON: manifestJSON,
-        guestSource: """
-        import json, sys
-        event = json.load(sys.stdin)
-        def emit(v):
-            json.dump(v, sys.stdout, separators=(",", ":"))
-        if event.get("http_results"):
-            emit([{"verb":"result.emit","sent_message":{"vendor_message_id":"1.0","created_at":"1710000001.0"}}])
-        else:
-            emit([{"verb":"http.request","request_id":"send-1","method":"POST","url":"https://slack.com/api/chat.postMessage"}])
-        """,
+        guestSource: connectorGuestGoSource(),
         testInput: testInput
     )
 }
 
+private func connectorGuestGoSource() -> String {
+    """
+    package main
+
+    import (
+        "encoding/json"
+        "os"
+    )
+
+    func main() {
+        var event map[string]any
+        _ = json.NewDecoder(os.Stdin).Decode(&event)
+        if _, ok := event["http_results"]; ok {
+            enc := json.NewEncoder(os.Stdout)
+            enc.SetEscapeHTML(false)
+            _ = enc.Encode([]map[string]any{{
+                "verb": "result.emit",
+                "sent_message": map[string]any{
+                    "vendor_message_id": "1.0",
+                    "created_at": "1710000001.0",
+                },
+            }})
+            return
+        }
+        enc := json.NewEncoder(os.Stdout)
+        enc.SetEscapeHTML(false)
+        _ = enc.Encode([]map[string]any{{
+            "verb": "http.request",
+            "request_id": "send-1",
+            "method": "POST",
+            "url": "https://slack.com/api/chat.postMessage",
+        }})
+    }
+    """
+}
+
 private actor SequenceFactoryBuilder: PluginFactoryBuilder {
     let drafts: [PluginFactoryDraft]
     private(set) var callCount = 0
diff --git a/packages/Structure/Sources/AppLayerServices/AppServices/ContainerLifecyclePolicy.swift b/packages/Structure/Sources/AppLayerServices/AppServices/ContainerLifecyclePolicy.swift
index 4ac3d26d..9f35e742 100644
--- a/packages/Structure/Sources/AppLayerServices/AppServices/ContainerLifecyclePolicy.swift
+++ b/packages/Structure/Sources/AppLayerServices/AppServices/ContainerLifecyclePolicy.swift
@@ -9,7 +9,7 @@ import Foundation
 public struct ContainerLifecyclePolicy: Sendable, Hashable {
     /// Maximum crawler containers at once (oneshot; own queue).
     public let maxNetworkContainers: Int
-    /// Maximum offline Python guest containers at once (`script_exec` / `plugin.invoke`).
+    /// Maximum offline Go guest containers at once (`script_exec` / `plugin.invoke`).
     public let maxOfflineContainers: Int
     /// Maximum file-extractor containers at once (oneshot; own queue).
     public let maxFileExtractContainers: Int
diff --git a/packages/Structure/Sources/AppLayerServices/AppServices/DerrickBundledText.swift b/packages/Structure/Sources/AppLayerServices/AppServices/DerrickBundledText.swift
index 7dace2ea..5e46fd36 100644
--- a/packages/Structure/Sources/AppLayerServices/AppServices/DerrickBundledText.swift
+++ b/packages/Structure/Sources/AppLayerServices/AppServices/DerrickBundledText.swift
@@ -50,7 +50,7 @@ public enum DerrickBundledText: Sendable {
     public static func formatCodeForModel(
         _ source: String,
         heading: String,
-        language: String = "python"
+        language: String = "go"
     ) -> String {
         """
         # \(heading)
diff --git a/packages/Structure/Sources/AppLayerServices/AppServices/ServiceHealth.swift b/packages/Structure/Sources/AppLayerServices/AppServices/ServiceHealth.swift
index 3cd83418..cb0c5969 100644
--- a/packages/Structure/Sources/AppLayerServices/AppServices/ServiceHealth.swift
+++ b/packages/Structure/Sources/AppLayerServices/AppServices/ServiceHealth.swift
@@ -12,12 +12,8 @@ public enum DerrickGuestRuntime: Sendable {
     /// Leftover Swift guest image tag reported by older daemons. Hygiene retires a mismatch.
     public static let swiftPluginDockerImage = "swiftlang/swift:nightly-6.4.x-noble"
 
-    /// Pullable Python image for offline guests (script_exec primary).
-    public static let pythonGuestDockerImage = "python:3.14.7"
-
-    /// Custom image with uv for packaged connector plugins.
-    /// Build: `docker build -f docker/guest-runtime/Dockerfile -t derrick-guest-runtime:python-v1 .`
-    public static let pythonGuestDockerImageWithUV = "derrick-guest-runtime:python-v1"
+    /// Unified Go worker image for offline guests (`script_exec` / `plugin.invoke`).
+    public static let guestDockerImage = DockerWorkerRuntime.image
 }
 
 public struct ServiceHealthReport: Codable, Sendable, Hashable {
diff --git a/packages/Structure/Sources/AppLayerServices/MCPService/EffectorAdmissionPolicy.swift b/packages/Structure/Sources/AppLayerServices/MCPService/EffectorAdmissionPolicy.swift
index 0a69752b..5604b30b 100644
--- a/packages/Structure/Sources/AppLayerServices/MCPService/EffectorAdmissionPolicy.swift
+++ b/packages/Structure/Sources/AppLayerServices/MCPService/EffectorAdmissionPolicy.swift
@@ -6,10 +6,14 @@ public enum EffectorAdmissionPolicy: Sendable {
         context: ExecutionContextWire?,
         principal: ServicePrincipal
     ) -> Bool {
-        if case .job = principal { return true }
-        guard let context else { return false }
-        if context.capabilities.contains(.syncWebCrawl) { return true }
-        if context.workflow?.kind == .pluginFactoryCreate { return true }
+        switch principal {
+        case .job, .agent:
+            return true
+        default:
+            break
+        }
+        if let context, context.capabilities.contains(.syncWebCrawl) { return true }
+        if let context, context.workflow?.kind == .pluginFactoryCreate { return true }
         return false
     }
 
diff --git a/packages/Structure/Sources/AppLayerServices/MCPService/MCPServiceXPC.swift b/packages/Structure/Sources/AppLayerServices/MCPService/MCPServiceXPC.swift
index 1acf6952..5d3808f0 100644
--- a/packages/Structure/Sources/AppLayerServices/MCPService/MCPServiceXPC.swift
+++ b/packages/Structure/Sources/AppLayerServices/MCPService/MCPServiceXPC.swift
@@ -45,7 +45,7 @@ public struct MCPToolCallRequest: Codable, Sendable, Hashable {
     /// JSON `HelperModelWire` for script security reviewer model selection.
     /// When nil, MCPService uses the default helper model.
     public let helperReviewerModelJSON: String?
-    /// When true, MCPService allows synchronous `web.crawl` (interactive `/create-plugin` turns).
+    /// When true, plugin factory creation is active for this call.
     /// Deprecated: use `executionContextJSON` (ExecutionContextWire).
     public let pluginFactoryCreationActive: Bool
     /// JSON `ExecutionContextWire` for cross-boundary policy and effector admission.
diff --git a/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateFailureMessage.swift b/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateFailureMessage.swift
index 0a72e146..10ef8ffb 100644
--- a/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateFailureMessage.swift
+++ b/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateFailureMessage.swift
@@ -92,8 +92,8 @@ public enum PluginFactoryCreateFailureMessage: Sendable {
         if message.count > 160 { return true }
         let prefixes = [
             "Invalid Agent Plugin manifest",
-            "Invalid Python guest source",
-            "Python draft test failed",
+            "Invalid Go guest source",
+            "Go draft test failed",
             "Plugin review rejected",
             "Draft validation failed:",
         ]
diff --git a/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateInput.swift b/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateInput.swift
index 001ae388..a152366d 100644
--- a/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateInput.swift
+++ b/packages/Structure/Sources/AppLayerServices/MCPService/PluginFactoryCreateInput.swift
@@ -4,7 +4,6 @@ import Foundation
 public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
     public enum PluginType: String, Codable, Sendable, CaseIterable {
         case connector
-        case newsReader = "news_reader"
         case custom
     }
 
@@ -93,6 +92,7 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
     public let description: String
     public let pluginID: String?
     public let auth: ConnectorAuthDiscovery?
+    public let skillMarkdown: String?
 
     public init(
         pluginType: PluginType,
@@ -101,7 +101,8 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
         scope: ConnectorScope = .fullSync,
         description: String,
         pluginID: String? = nil,
-        auth: ConnectorAuthDiscovery? = nil
+        auth: ConnectorAuthDiscovery? = nil,
+        skillMarkdown: String? = nil
     ) {
         self.pluginType = pluginType
         self.vendor = vendor
@@ -109,6 +110,7 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
         self.scope = scope
         self.pluginID = pluginID?.trimmingCharacters(in: .whitespacesAndNewlines).nilIfEmpty
         self.auth = auth
+        self.skillMarkdown = skillMarkdown?.trimmingCharacters(in: .whitespacesAndNewlines).nilIfEmpty
         self.description = Self.resolvedDescription(
             userDescription: description,
             vendor: vendor,
@@ -117,6 +119,37 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
         )
     }
 
+    public static func makeFromSkillDraft(
+        _ draft: PluginSkillDraft,
+        auth: ConnectorAuthDiscovery? = nil
+    ) throws -> PluginFactoryCreateInput {
+        let pluginID = try draft.normalizedPluginID()
+        let description = draft.factoryDescription()
+        let skillMarkdown = draft.skillMarkdown()
+        switch draft.plannedKind {
+        case .messagingConnector:
+            guard let vendor = draft.inferredConnectorVendor else {
+                throw PluginSkillDraftError.missingConnectorVendor
+            }
+            return PluginFactoryCreateInput(
+                pluginType: .connector,
+                vendor: vendor,
+                scope: .fullSync,
+                description: description,
+                pluginID: pluginID,
+                auth: auth,
+                skillMarkdown: skillMarkdown
+            )
+        case .customCapability:
+            return PluginFactoryCreateInput(
+                pluginType: .custom,
+                description: description,
+                pluginID: pluginID,
+                skillMarkdown: skillMarkdown
+            )
+        }
+    }
+
     /// Builds connector workflow input. The factory goal uses the fixed scope sentence, not free-text extras.
     public static func makeConnector(
         vendor: ConnectorVendor,
@@ -137,7 +170,8 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
             scope: scope,
             description: userDescription,
             pluginID: resolvedID,
-            auth: auth ?? (try? ConnectorAuthDiscovery.slackBotTokenFallback())
+            auth: auth ?? (try? ConnectorAuthDiscovery.slackBotTokenFallback()),
+            skillMarkdown: nil
         )
     }
 
@@ -182,6 +216,7 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
         case description
         case pluginID
         case auth
+        case skillMarkdown
     }
 
     public init(from decoder: Decoder) throws {
@@ -195,6 +230,8 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
         pluginID = try container.decodeIfPresent(String.self, forKey: .pluginID)?
             .trimmingCharacters(in: .whitespacesAndNewlines).nilIfEmpty
         auth = try container.decodeIfPresent(ConnectorAuthDiscovery.self, forKey: .auth)
+        skillMarkdown = try container.decodeIfPresent(String.self, forKey: .skillMarkdown)?
+            .trimmingCharacters(in: .whitespacesAndNewlines).nilIfEmpty
         description = Self.resolvedDescription(
             userDescription: rawDescription,
             vendor: vendor,
@@ -212,6 +249,7 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
         try container.encode(description, forKey: .description)
         try container.encodeIfPresent(pluginID, forKey: .pluginID)
         try container.encodeIfPresent(auth, forKey: .auth)
+        try container.encodeIfPresent(skillMarkdown, forKey: .skillMarkdown)
     }
 
     public func encodedJSON() throws -> String {
@@ -247,8 +285,11 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
                     extra.append("Host permission labels: \(auth.permissions.joined(separator: ", "))")
                 }
             }
+            if let skillMarkdown, !skillMarkdown.isEmpty {
+                extra.append("SKILL.md draft:\n\(skillMarkdown)")
+            }
             extra.append(
-                "The host writes plugin.json. Return python_source and test_input_json only. Do not invent a plugin_id or secrets list."
+                "The host writes plugin.json. Return go_source and test_input_json only. Do not invent a plugin_id or secrets list."
             )
             return try ConnectorContractPrompts.factoryGoal(
                 vendorLabel: vendorLabel,
@@ -267,31 +308,43 @@ public struct PluginFactoryCreateInput: Codable, Sendable, Hashable {
         }
     }
 
-    /// Failure stage hint for returning the wizard to the right step.
+    public func customBuildGoal() -> String {
+        var lines = [
+            "Create an Agent Plugin capability.",
+            description,
+        ]
+        if let skillMarkdown, !skillMarkdown.isEmpty {
+            lines.append("SKILL.md draft:\n\(skillMarkdown)")
+        }
+        lines.append(
+            "Return go_source, test_input_json, and skill_files. Include a valid plugin.json via the builder contract when no host manifest is supplied."
+        )
+        return lines.joined(separator: "\n\n")
+    }
+
+    /// Failure stage hint for returning the plugin studio to the right step.
     public enum FailureStep: String, Sendable {
-        case type
-        case vendor
-        case name
-        case auth
-        case news
-        case description
-        case creating
+        case goal
+        case skill
+        case preview
+        case credentials
+        case build
     }
 
     public static func failureStep(forStage stage: String?) -> FailureStep {
         switch stage?.lowercased() {
-        case "type":
-            return .type
-        case "name":
-            return .name
-        case "auth", "discover":
-            return .auth
-        case "news", "paywall":
-            return .news
-        case "crawl", "docs", "vendor", "factory", "build", "review", "description":
-            return .vendor
+        case "goal":
+            return .goal
+        case "skill", "name", "description", "type", "vendor":
+            return .skill
+        case "preview":
+            return .preview
+        case "auth", "discover", "credentials":
+            return .credentials
+        case "crawl", "docs", "factory", "build", "review":
+            return .build
         default:
-            return .creating
+            return .build
         }
     }
 }
diff --git a/packages/Structure/Sources/AppLayerServices/News/NewsFeedParser.swift b/packages/Structure/Sources/AppLayerServices/News/NewsFeedParser.swift
deleted file mode 100644
index ebfd4f9b..00000000
--- a/packages/Structure/Sources/AppLayerServices/News/NewsFeedParser.swift
+++ /dev/null
@@ -1,154 +0,0 @@
-import Foundation
-
-public enum NewsFeedParser {
-    public static func parse(data: Data, sourceLabel: String, fallbackPageURL: URL) -> [ParsedNewsEntry] {
-        let text = String(data: data, encoding: .utf8)
-            ?? String(data: data, encoding: .isoLatin1)
-            ?? ""
-        if NewsPaywall.looksLikeFeed(text) {
-            return parseXMLFeed(text, sourceLabel: sourceLabel)
-        }
-        if let entry = htmlFallback(text: text, sourceLabel: sourceLabel, url: fallbackPageURL) {
-            return [entry]
-        }
-        return []
-    }
-
-    public struct ParsedNewsEntry: Sendable, Hashable {
-        public var title: String
-        public var sourceURL: String
-        public var summary: String?
-        public var publishedAt: Date?
-
-        public init(title: String, sourceURL: String, summary: String? = nil, publishedAt: Date? = nil) {
-            self.title = title
-            self.sourceURL = sourceURL
-            self.summary = summary
-            self.publishedAt = publishedAt
-        }
-    }
-
-    private static func parseXMLFeed(_ xml: String, sourceLabel: String) -> [ParsedNewsEntry] {
-        _ = sourceLabel
-        var entries: [ParsedNewsEntry] = []
-        let itemBlocks = slices(of: xml, start: "<item", end: "</item>")
-            + slices(of: xml, start: "<entry", end: "</entry>")
-        for block in itemBlocks {
-            let title = firstTag(block, names: ["title"]) ?? ""
-            let link = firstTag(block, names: ["link"])
-                ?? attribute(named: "href", in: firstRawTag(block, name: "link") ?? "")
-                ?? firstTag(block, names: ["guid", "id"])
-                ?? ""
-            let summary = firstTag(block, names: ["description", "summary", "content"])
-            let dateText = firstTag(block, names: ["pubDate", "published", "updated", "dc:date"])
-            let cleanedTitle = stripTags(title).trimmingCharacters(in: .whitespacesAndNewlines)
-            let cleanedLink = stripTags(link).trimmingCharacters(in: .whitespacesAndNewlines)
-            guard !cleanedTitle.isEmpty, let url = URL(string: cleanedLink), url.scheme != nil else {
-                continue
-            }
-            entries.append(
-                ParsedNewsEntry(
-                    title: cleanedTitle,
-                    sourceURL: url.absoluteString,
-                    summary: summary.map(stripTags).flatMap { $0.isEmpty ? nil : $0 },
-                    publishedAt: parseDate(dateText)
-                )
-            )
-        }
-        return entries
-    }
-
-    private static func htmlFallback(text: String, sourceLabel: String, url: URL) -> ParsedNewsEntry? {
-        _ = sourceLabel
-        let title = firstTag(text, names: ["title"])
-            .map(stripTags)?
-            .trimmingCharacters(in: .whitespacesAndNewlines)
-        guard let title, !title.isEmpty else { return nil }
-        return ParsedNewsEntry(title: title, sourceURL: url.absoluteString, summary: nil, publishedAt: nil)
-    }
-
-    private static func slices(of text: String, start: String, end: String) -> [String] {
-        var result: [String] = []
-        let startLower = start.lowercased()
-        let endLower = end.lowercased()
-        let lower = text.lowercased()
-        var idx = lower.startIndex
-        while let startRange = lower[idx...].range(of: startLower) {
-            guard let endRange = lower[startRange.upperBound...].range(of: endLower) else { break }
-            let sliceStart = startRange.lowerBound
-            let sliceEnd = endRange.upperBound
-            result.append(String(text[sliceStart..<sliceEnd]))
-            idx = sliceEnd
-        }
-        return result
-    }
-
-    private static func firstTag(_ xml: String, names: [String]) -> String? {
-        for name in names {
-            let lower = xml.lowercased()
-            let open = "<\(name.lowercased())"
-            guard let openStart = lower.range(of: open) else { continue }
-            guard let tagClose = xml[openStart.upperBound...].firstIndex(of: ">") else { continue }
-            let innerStart = xml.index(after: tagClose)
-            let closeToken = "</\(name.lowercased())>"
-            guard let close = lower[innerStart...].range(of: closeToken) else { continue }
-            return String(xml[innerStart..<close.lowerBound])
-        }
-        return nil
-    }
-
-    private static func firstRawTag(_ xml: String, name: String) -> String? {
-        let lower = xml.lowercased()
-        let open = "<\(name.lowercased())"
-        guard let openStart = lower.range(of: open) else { return nil }
-        guard let tagClose = xml[openStart.upperBound...].firstIndex(of: ">") else { return nil }
-        return String(xml[openStart.lowerBound...tagClose])
-    }
-
-    private static func attribute(named name: String, in tag: String) -> String? {
-        let pattern = "\(name)\\s*=\\s*\"([^\"]+)\""
-        guard let regex = try? NSRegularExpression(pattern: pattern, options: .caseInsensitive) else {
-            return nil
-        }
-        let range = NSRange(tag.startIndex..<tag.endIndex, in: tag)
-        guard let match = regex.firstMatch(in: tag, range: range), match.numberOfRanges > 1,
-              let inner = Range(match.range(at: 1), in: tag)
-        else {
-            return nil
-        }
-        return String(tag[inner])
-    }
-
-    private static func stripTags(_ raw: String) -> String {
-        var value = raw.replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression)
-        let entities: [(String, String)] = [
-            ("&amp;", "&"),
-            ("&lt;", "<"),
-            ("&gt;", ">"),
-            ("&quot;", "\""),
-            ("&#39;", "'"),
-            ("&apos;", "'"),
-            ("&nbsp;", " "),
-        ]
-        for (from, to) in entities {
-            value = value.replacingOccurrences(of: from, with: to)
-        }
-        return value
-    }
-
-    private static func parseDate(_ raw: String?) -> Date? {
-        guard let raw, !raw.isEmpty else { return nil }
-        let trimmed = raw.trimmingCharacters(in: .whitespacesAndNewlines)
-        let rfc = DateFormatter()
-        rfc.locale = Locale(identifier: "en_US_POSIX")
-        rfc.dateFormat = "EEE, dd MMM yyyy HH:mm:ss Z"
-        if let date = rfc.date(from: trimmed) { return date }
-        rfc.dateFormat = "EEE, dd MMM yyyy HH:mm:ss zzz"
-        if let date = rfc.date(from: trimmed) { return date }
-        let iso = ISO8601DateFormatter()
-        iso.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
-        if let date = iso.date(from: trimmed) { return date }
-        iso.formatOptions = [.withInternetDateTime]
-        return iso.date(from: trimmed)
-    }
-}
diff --git a/packages/Structure/Sources/AppLayerServices/News/NewsReaderModels.swift b/packages/Structure/Sources/AppLayerServices/News/NewsReaderModels.swift
deleted file mode 100644
index f09967e2..00000000
--- a/packages/Structure/Sources/AppLayerServices/News/NewsReaderModels.swift
+++ /dev/null
@@ -1,187 +0,0 @@
-import Foundation
-
-public enum NewsReaderMode: String, Codable, Sendable, Hashable, CaseIterable {
-    case list
-    case summaries
-
-    public var displayName: String {
-        switch self {
-        case .list: return "List articles"
-        case .summaries: return "Summaries"
-        }
-    }
-}
-
-public enum NewsReaderSchedule: String, Codable, Sendable, Hashable, CaseIterable {
-    case off
-    case hourly
-    case daily
-
-    public var displayName: String {
-        switch self {
-        case .off: return "Only when opened"
-        case .hourly: return "Every hour"
-        case .daily: return "Every day"
-        }
-    }
-}
-
-public struct NewsSource: Codable, Sendable, Hashable, Identifiable {
-    public var id: String
-    public var label: String
-    public var url: String
-
-    public init(id: String = UUID().uuidString, label: String, url: String) {
-        self.id = id
-        self.label = label
-        self.url = url.trimmingCharacters(in: .whitespacesAndNewlines)
-    }
-}
-
-public struct NewsReaderSpec: Codable, Sendable, Hashable, Identifiable {
-    public var id: String
-    public var name: String
-    public var topics: [String]
-    public var sources: [NewsSource]
-    public var mode: NewsReaderMode
-    public var maxCount: Int
-    public var schedule: NewsReaderSchedule
-    public var lastError: String?
-    public var lastFetchedAt: Date?
-    public var createdAt: Date
-    public var updatedAt: Date
-
-    public init(
-        id: String = UUID().uuidString,
-        name: String,
-        topics: [String],
-        sources: [NewsSource],
-        mode: NewsReaderMode = .list,
-        maxCount: Int = 20,
-        schedule: NewsReaderSchedule = .off,
-        lastError: String? = nil,
-        lastFetchedAt: Date? = nil,
-        createdAt: Date = .now,
-        updatedAt: Date = .now
-    ) {
-        self.id = id
-        self.name = name.trimmingCharacters(in: .whitespacesAndNewlines)
-        self.topics = topics.map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }.filter { !$0.isEmpty }
-        self.sources = sources.filter { !$0.url.isEmpty }
-        self.mode = mode
-        self.maxCount = min(50, max(1, maxCount))
-        self.schedule = schedule
-        self.lastError = lastError
-        self.lastFetchedAt = lastFetchedAt
-        self.createdAt = createdAt
-        self.updatedAt = updatedAt
-    }
-}
-
-public struct NewsItem: Codable, Sendable, Hashable, Identifiable {
-    public var id: String
-    public var readerID: String
-    public var title: String
-    public var sourceURL: String
-    public var sourceLabel: String
-    public var summary: String?
-    public var publishedAt: Date?
-    public var fetchedAt: Date
-
-    public init(
-        id: String = UUID().uuidString,
-        readerID: String,
-        title: String,
-        sourceURL: String,
-        sourceLabel: String,
-        summary: String? = nil,
-        publishedAt: Date? = nil,
-        fetchedAt: Date = .now
-    ) {
-        self.id = id
-        self.readerID = readerID
-        self.title = title.trimmingCharacters(in: .whitespacesAndNewlines)
-        self.sourceURL = sourceURL.trimmingCharacters(in: .whitespacesAndNewlines)
-        self.sourceLabel = sourceLabel
-        self.summary = summary?.trimmingCharacters(in: .whitespacesAndNewlines)
-        self.publishedAt = publishedAt
-        self.fetchedAt = fetchedAt
-    }
-}
-
-public enum NewsPresetTopic: String, Sendable, CaseIterable, Identifiable {
-    case financial
-    case tech
-    case international
-    case politics
-    case science
-    case sports
-
-    public var id: String { rawValue }
-
-    public var displayName: String {
-        switch self {
-        case .financial: return "Financial"
-        case .tech: return "Tech"
-        case .international: return "International"
-        case .politics: return "Politics"
-        case .science: return "Science"
-        case .sports: return "Sports"
-        }
-    }
-}
-
-public enum NewsPresetSource: String, Sendable, CaseIterable, Identifiable {
-    case bbcWorld
-    case npr
-    case bbcTech
-    case hn
-    case googleNews
-
-    public var id: String { rawValue }
-
-    public var source: NewsSource {
-        switch self {
-        case .bbcWorld:
-            return NewsSource(id: rawValue, label: "BBC World", url: "https://feeds.bbci.co.uk/news/world/rss.xml")
-        case .npr:
-            return NewsSource(id: rawValue, label: "NPR", url: "https://feeds.npr.org/1001/rss.xml")
-        case .bbcTech:
-            return NewsSource(id: rawValue, label: "BBC Technology", url: "https://feeds.bbci.co.uk/news/technology/rss.xml")
-        case .hn:
-            return NewsSource(id: rawValue, label: "Hacker News", url: "https://hnrss.org/frontpage")
-        case .googleNews:
-            return NewsSource(
-                id: rawValue,
-                label: "Google News",
-                url: "https://news.google.com/rss?hl=en-US&gl=US&ceid=US:en"
-            )
-        }
-    }
-}
-
-public enum NewsReaderError: Error, Sendable, Equatable, LocalizedError {
-    case paywalled(url: String, detail: String)
-    case invalidURL(String)
-    case emptySources
-    case emptyName
-    case fetchFailed(url: String, detail: String)
-    case notReady
-
-    public var errorDescription: String? {
-        switch self {
-        case .paywalled(let url, let detail):
-            return "This source is behind a paywall, which is not supported yet. \(detail) (\(url))"
-        case .invalidURL(let url):
-            return "That is not a usable web address: \(url)"
-        case .emptySources:
-            return "Add at least one source or URL."
-        case .emptyName:
-            return "Give this news list a name."
-        case .fetchFailed(let url, let detail):
-            return "Could not read \(url). \(detail)"
-        case .notReady:
-            return "News lists are not ready yet. Try again in a moment."
-        }
-    }
-}
diff --git a/packages/Structure/Sources/AppLayerServices/News/NewsReaderRefresh.swift b/packages/Structure/Sources/AppLayerServices/News/NewsReaderRefresh.swift
deleted file mode 100644
index 37c362f8..00000000
--- a/packages/Structure/Sources/AppLayerServices/News/NewsReaderRefresh.swift
+++ /dev/null
@@ -1,139 +0,0 @@
-import Foundation
-
-public protocol NewsHTTPClient: Sendable {
-    func get(url: URL) async throws -> NewsHTTPResponse
-}
-
-public struct NewsHTTPResponse: Sendable {
-    public var status: Int
-    public var contentType: String?
-    public var body: Data
-
-    public init(status: Int, contentType: String?, body: Data) {
-        self.status = status
-        self.contentType = contentType
-        self.body = body
-    }
-}
-
-public struct URLSessionNewsHTTPClient: NewsHTTPClient {
-    public init() {}
-
-    public func get(url: URL) async throws -> NewsHTTPResponse {
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.timeoutInterval = 20
-        request.setValue(
-            "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Safari/605.1.15",
-            forHTTPHeaderField: "User-Agent"
-        )
-        request.setValue("application/rss+xml, application/atom+xml, application/xml, text/xml, text/html;q=0.8", forHTTPHeaderField: "Accept")
-        let (data, response) = try await URLSession.shared.data(for: request)
-        let http = response as? HTTPURLResponse
-        return NewsHTTPResponse(
-            status: http?.statusCode ?? 0,
-            contentType: http?.value(forHTTPHeaderField: "Content-Type"),
-            body: data
-        )
-    }
-}
-
-public enum NewsReaderRefresh {
-    public static func validateAndFetch(
-        spec: NewsReaderSpec,
-        client: any NewsHTTPClient
-    ) async throws -> [NewsItem] {
-        let name = spec.name.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !name.isEmpty else { throw NewsReaderError.emptyName }
-        guard !spec.sources.isEmpty else { throw NewsReaderError.emptySources }
-
-        var collected: [NewsItem] = []
-        for source in spec.sources {
-            let parsed = try await fetchSource(source, readerID: spec.id, client: client)
-            collected.append(contentsOf: parsed)
-        }
-
-        let filtered = filter(collected, topics: spec.topics)
-        let unique = uniqued(filtered)
-        let sorted = unique.sorted { lhs, rhs in
-            (lhs.publishedAt ?? lhs.fetchedAt) > (rhs.publishedAt ?? rhs.fetchedAt)
-        }
-        return Array(sorted.prefix(spec.maxCount))
-    }
-
-    public static func digest(from items: [NewsItem]) -> String {
-        let lines = items.prefix(8).map { item in
-            "• \(item.title) (\(item.sourceLabel))"
-        }
-        return lines.joined(separator: "\n")
-    }
-
-    private static func fetchSource(
-        _ source: NewsSource,
-        readerID: String,
-        client: any NewsHTTPClient
-    ) async throws -> [NewsItem] {
-        guard let url = URL(string: source.url), url.scheme == "http" || url.scheme == "https" else {
-            throw NewsReaderError.invalidURL(source.url)
-        }
-        let fetchURL = NewsSourceURL.canonicalFetchURL(url)
-        if let reason = NewsPaywall.preflightRejection(url: fetchURL) {
-            throw NewsReaderError.paywalled(url: source.url, detail: reason)
-        }
-        let response: NewsHTTPResponse
-        do {
-            response = try await client.get(url: fetchURL)
-        } catch {
-            throw NewsReaderError.fetchFailed(url: source.url, detail: error.localizedDescription)
-        }
-        if let reason = NewsPaywall.rejectionReason(
-            url: fetchURL,
-            status: response.status,
-            contentType: response.contentType,
-            body: response.body
-        ) {
-            throw NewsReaderError.paywalled(url: source.url, detail: reason)
-        }
-        if response.status != 0, response.status < 200 || response.status >= 400 {
-            throw NewsReaderError.fetchFailed(url: source.url, detail: "HTTP \(response.status)")
-        }
-        let entries = NewsFeedParser.parse(data: response.body, sourceLabel: source.label, fallbackPageURL: fetchURL)
-        guard !entries.isEmpty else {
-            throw NewsReaderError.fetchFailed(
-                url: source.url,
-                detail: "No articles were found. For Google News, Derrick uses the public RSS feed."
-            )
-        }
-        return entries.map { entry in
-            NewsItem(
-                readerID: readerID,
-                title: entry.title,
-                sourceURL: entry.sourceURL,
-                sourceLabel: source.label,
-                summary: entry.summary,
-                publishedAt: entry.publishedAt
-            )
-        }
-    }
-
-    private static func filter(_ items: [NewsItem], topics: [String]) -> [NewsItem] {
-        let needles = topics.map { $0.lowercased() }.filter { !$0.isEmpty }
-        guard !needles.isEmpty else { return items }
-        let matched = items.filter { item in
-            let hay = "\(item.title) \(item.summary ?? "")".lowercased()
-            return needles.contains { hay.contains($0) }
-        }
-        return matched.isEmpty ? items : matched
-    }
-
-    private static func uniqued(_ items: [NewsItem]) -> [NewsItem] {
-        var seen = Set<String>()
-        var result: [NewsItem] = []
-        for item in items {
-            if seen.insert(item.sourceURL).inserted {
-                result.append(item)
-            }
-        }
-        return result
-    }
-}
diff --git a/packages/Structure/Sources/AppLayerServices/News/NewsSourceURL.swift b/packages/Structure/Sources/AppLayerServices/News/NewsSourceURL.swift
index a07e64af..454b7d6b 100644
--- a/packages/Structure/Sources/AppLayerServices/News/NewsSourceURL.swift
+++ b/packages/Structure/Sources/AppLayerServices/News/NewsSourceURL.swift
@@ -2,30 +2,86 @@ import Foundation
 
 /// Rewrites well-known news homepages to a public RSS/Atom endpoint the host can parse.
 public enum NewsSourceURL {
-    public static func canonicalFetchURL(_ url: URL) -> URL {
+    /// Rewrites Google News HTML/topic URLs to RSS feeds the host can fetch reliably.
+    /// `contextHint` may carry a crawl goal or user prompt (for example "tech news").
+    public static func canonicalFetchURL(_ url: URL, contextHint: String? = nil) -> URL {
         let host = (url.host ?? "").lowercased()
         guard isGoogleNewsHost(host) else { return url }
         let path = url.path.lowercased()
         if path.contains("/rss") || path.hasSuffix(".xml") {
+            if !path.contains("/headlines/section/topic/"),
+               let section = googleNewsSection(from: contextHint) {
+                return googleNewsSectionRSS(section: section)
+            }
             return url
         }
+        if path.contains("/topics/") {
+            if let section = googleNewsSection(from: contextHint) {
+                return googleNewsSectionRSS(section: section)
+            }
+            return googleNewsGeneralRSS()
+        }
         var parts = URLComponents(url: url, resolvingAgainstBaseURL: false) ?? URLComponents()
         parts.scheme = "https"
         parts.host = "news.google.com"
         parts.path = "/rss"
         if parts.queryItems == nil || parts.queryItems?.isEmpty == true {
-            parts.queryItems = [
-                URLQueryItem(name: "hl", value: "en-US"),
-                URLQueryItem(name: "gl", value: "US"),
-                URLQueryItem(name: "ceid", value: "US:en"),
-            ]
+            parts.queryItems = defaultLocaleQueryItems
         }
         parts.fragment = nil
-        return parts.url ?? URL(string: "https://news.google.com/rss?hl=en-US&gl=US&ceid=US:en")!
+        return parts.url ?? googleNewsGeneralRSS()
     }
 
     public static func isGoogleNewsHost(_ host: String) -> Bool {
         let value = host.lowercased()
         return value == "news.google.com" || value.hasSuffix(".news.google.com")
     }
+
+    private static let defaultLocaleQueryItems = [
+        URLQueryItem(name: "hl", value: "en-US"),
+        URLQueryItem(name: "gl", value: "US"),
+        URLQueryItem(name: "ceid", value: "US:en"),
+    ]
+
+    private static func googleNewsGeneralRSS() -> URL {
+        URL(string: "https://news.google.com/rss?hl=en-US&gl=US&ceid=US:en")!
+    }
+
+    private static func googleNewsSectionRSS(section: String) -> URL {
+        var parts = URLComponents()
+        parts.scheme = "https"
+        parts.host = "news.google.com"
+        parts.path = "/rss/headlines/section/topic/\(section)"
+        parts.queryItems = defaultLocaleQueryItems
+        return parts.url ?? googleNewsGeneralRSS()
+    }
+
+    private static func googleNewsSection(from contextHint: String?) -> String? {
+        let hint = (contextHint ?? "")
+            .lowercased()
+            .replacingOccurrences(of: "-", with: " ")
+            .replacingOccurrences(of: "_", with: " ")
+        if hint.contains("tech") {
+            return "TECHNOLOGY"
+        }
+        if hint.contains("business") || hint.contains("finance") || hint.contains("market") {
+            return "BUSINESS"
+        }
+        if hint.contains("science") {
+            return "SCIENCE"
+        }
+        if hint.contains("sport") {
+            return "SPORTS"
+        }
+        if hint.contains("health") {
+            return "HEALTH"
+        }
+        if hint.contains("entertainment") {
+            return "ENTERTAINMENT"
+        }
+        if hint.contains("world") {
+            return "WORLD"
+        }
+        return nil
+    }
 }
diff --git a/packages/Structure/Sources/AppLayerServices/Plugin/PluginSkillDraft.swift b/packages/Structure/Sources/AppLayerServices/Plugin/PluginSkillDraft.swift
new file mode 100644
index 00000000..f6b7d28d
--- /dev/null
+++ b/packages/Structure/Sources/AppLayerServices/Plugin/PluginSkillDraft.swift
@@ -0,0 +1,352 @@
+import Foundation
+
+/// User-authored Agent Plugin intent before the factory materializes plugin.json, SKILL.md, and guest code.
+public struct PluginSkillDraft: Sendable, Hashable {
+    public enum Trigger: String, Sendable, CaseIterable, Codable, Hashable {
+        case chat
+        case messaging
+        case schedule
+        case mention
+
+        public var label: String {
+            switch self {
+            case .chat: return "When I ask in chat"
+            case .messaging: return "From Messaging"
+            case .schedule: return "On a schedule"
+            case .mention: return "When I type /plugin-name"
+            }
+        }
+    }
+
+    public struct Example: Sendable, Hashable, Identifiable {
+        public var id: String
+        public var userSays: String
+        public var pluginDoes: String
+
+        public init(id: String = UUID().uuidString, userSays: String, pluginDoes: String) {
+            self.id = id
+            self.userSays = userSays
+            self.pluginDoes = pluginDoes
+        }
+    }
+
+    public enum PlannedKind: String, Sendable, Hashable {
+        case messagingConnector
+        case customCapability
+    }
+
+    public var goal: String
+    public var purpose: String
+    public var triggers: Set<Trigger>
+    public var examples: [Example]
+    public var pluginName: String
+
+    public init(
+        goal: String = "",
+        purpose: String = "",
+        triggers: Set<Trigger> = [.chat],
+        examples: [Example] = [],
+        pluginName: String = ""
+    ) {
+        self.goal = goal
+        self.purpose = purpose
+        self.triggers = triggers
+        self.examples = examples
+        self.pluginName = pluginName
+    }
+
+    public var plannedKind: PlannedKind {
+        PluginSkillDraftPlanner.inferKind(from: self)
+    }
+
+    public var inferredConnectorVendor: PluginFactoryCreateInput.ConnectorVendor? {
+        PluginSkillDraftPlanner.inferConnectorVendor(from: self)
+    }
+
+    public var isBuildable: Bool {
+        switch plannedKind {
+        case .messagingConnector:
+            return inferredConnectorVendor?.isSelectableInWizard == true
+        case .customCapability:
+            return true
+        }
+    }
+
+    public var buildBlockedReason: String? {
+        if plannedKind == .messagingConnector,
+           inferredConnectorVendor?.isSelectableInWizard != true {
+            let label = inferredConnectorVendor?.displayName ?? "That service"
+            return "\(label) messaging connectors are not available yet. Try Slack or describe a custom capability."
+        }
+        return nil
+    }
+
+    public func isTriggerAvailable(_ trigger: Trigger) -> Bool {
+        PluginSkillDraftPlanner.availableTriggers(for: plannedKind).contains(trigger)
+    }
+
+    public func skillMarkdown() -> String {
+        PluginSkillDraftPlanner.skillMarkdown(for: self)
+    }
+
+    public func previewScenarios() -> [String] {
+        examples.map { example in
+            "When you say “\(example.userSays)”, the plugin will \(example.pluginDoes)."
+        }
+    }
+
+    public func packageOutline() -> [String] {
+        switch plannedKind {
+        case .messagingConnector, .customCapability:
+            return [
+                "plugin.json — name, permissions, and secrets",
+                "skills/\(normalizedPluginFolderName())/SKILL.md — purpose and examples",
+                "app.derrick/plugin.go — guest program (compiled in Docker)",
+                "app.derrick/plugin — compiled binary",
+            ]
+        }
+    }
+
+    public func factoryDescription() -> String {
+        PluginSkillDraftPlanner.factoryDescription(for: self)
+    }
+
+    public func normalizedPluginID() throws -> String {
+        try PluginID.normalized(pluginName).rawValue
+    }
+
+    private func normalizedPluginFolderName() -> String {
+        let trimmed = pluginName.trimmingCharacters(in: .whitespacesAndNewlines)
+        if trimmed.isEmpty { return "plugin" }
+        return trimmed
+            .lowercased()
+            .replacingOccurrences(of: #"[^a-z0-9]+"#, with: "-", options: .regularExpression)
+            .trimmingCharacters(in: CharacterSet(charactersIn: "-"))
+    }
+}
+
+public enum PluginSkillDraftPlanner {
+    public static func availableTriggers(
+        for kind: PluginSkillDraft.PlannedKind
+    ) -> Set<PluginSkillDraft.Trigger> {
+        switch kind {
+        case .messagingConnector:
+            return [.chat, .messaging, .mention]
+        case .customCapability:
+            return [.chat, .mention, .schedule]
+        }
+    }
+
+    public static func sanitizeTriggers(in draft: inout PluginSkillDraft) {
+        let allowed = availableTriggers(for: draft.plannedKind)
+        draft.triggers = draft.triggers.intersection(allowed)
+        if draft.triggers.isEmpty {
+            draft.triggers = defaultTriggers(for: draft)
+        }
+    }
+
+    public static func inferKind(from draft: PluginSkillDraft) -> PluginSkillDraft.PlannedKind {
+        let text = combinedText(draft)
+        if looksLikeMessaging(text) { return .messagingConnector }
+        return .customCapability
+    }
+
+    public static func inferConnectorVendor(
+        from draft: PluginSkillDraft
+    ) -> PluginFactoryCreateInput.ConnectorVendor? {
+        let text = combinedText(draft)
+        if text.contains("slack") { return .slack }
+        if text.contains("telegram") { return .telegram }
+        if text.contains("whatsapp") { return .whatsapp }
+        if text.contains("discord") { return .discord }
+        if inferKind(from: draft) == .messagingConnector { return .slack }
+        return nil
+    }
+
+    public static func applyGoal(_ goal: String, to draft: inout PluginSkillDraft, existingPluginIDs: [String]) {
+        let trimmed = goal.trimmingCharacters(in: .whitespacesAndNewlines)
+        draft.goal = trimmed
+        if draft.purpose.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+            draft.purpose = trimmed
+        }
+        if draft.pluginName.isEmpty {
+            draft.pluginName = suggestPluginName(for: draft, existingIDs: existingPluginIDs)
+        }
+        if draft.examples.isEmpty {
+            draft.examples = defaultExamples(for: draft)
+        }
+        if draft.triggers.isEmpty {
+            draft.triggers = defaultTriggers(for: draft)
+        }
+        sanitizeTriggers(in: &draft)
+    }
+
+    public static func skillMarkdown(for draft: PluginSkillDraft) -> String {
+        let name = draft.pluginName.trimmingCharacters(in: .whitespacesAndNewlines)
+        let triggerLines = draft.triggers.sorted { $0.rawValue < $1.rawValue }.map(\.label)
+        let exampleBlock = draft.examples.map { example in
+            """
+            ### User
+            \(example.userSays)
+
+            ### Plugin
+            \(example.pluginDoes)
+            """
+        }.joined(separator: "\n\n")
+
+        return """
+        # \(name.isEmpty ? "Plugin" : name)
+
+        ## Purpose
+        \(draft.purpose.trimmingCharacters(in: .whitespacesAndNewlines))
+
+        ## When to use
+        \(triggerLines.map { "- \($0)" }.joined(separator: "\n"))
+
+        ## Examples
+        \(exampleBlock.isEmpty ? "_Add at least one example before building._" : exampleBlock)
+        """
+    }
+
+    public static func factoryDescription(for draft: PluginSkillDraft) -> String {
+        let purpose = draft.purpose.trimmingCharacters(in: .whitespacesAndNewlines)
+        let examples = draft.examples
+            .map { "User: \($0.userSays) → Plugin: \($0.pluginDoes)" }
+            .joined(separator: "\n")
+        switch draft.plannedKind {
+        case .messagingConnector:
+            let vendor = inferConnectorVendor(from: draft)?.displayName ?? "messaging"
+            return """
+            \(purpose)
+
+            Messaging connector for \(vendor). List conversations as tabs, load messages including reply threads, and send messages.
+
+            Confirmed behavior:
+            \(examples)
+            """
+        case .customCapability:
+            return """
+            \(purpose)
+
+            Confirmed behavior:
+            \(examples)
+            """
+        }
+    }
+
+    public static func factoryGoal(
+        for draft: PluginSkillDraft,
+        crawlSummary: String?,
+        hostNotes: [String]
+    ) throws -> String {
+        let description = factoryDescription(for: draft)
+        switch draft.plannedKind {
+        case .messagingConnector:
+            guard let vendor = inferConnectorVendor(from: draft) else {
+                throw PluginSkillDraftError.missingConnectorVendor
+            }
+            var extra = hostNotes
+            extra.append("SKILL.md draft:\n\(skillMarkdown(for: draft))")
+            return try ConnectorContractPrompts.factoryGoal(
+                vendorLabel: vendor.displayName,
+                scope: .fullSync,
+                vendor: vendor,
+                crawlSummary: crawlSummary,
+                reference: extra.joined(separator: "\n"),
+                includeVendorBindings: true
+            )
+        case .customCapability:
+            return """
+            Create an Agent Plugin for this user goal.
+
+            \(description)
+
+            Host notes:
+            \(hostNotes.joined(separator: "\n"))
+
+            SKILL.md draft (write this into skills/):
+            \(skillMarkdown(for: draft))
+
+            Return go_source, test_input_json, and skill_files. The host writes plugin.json when a host manifest is supplied; otherwise include a valid manifest in your output path via the builder contract.
+            """
+        }
+    }
+
+    private static func combinedText(_ draft: PluginSkillDraft) -> String {
+        [draft.goal, draft.purpose, draft.pluginName]
+            .joined(separator: " ")
+            .lowercased()
+    }
+
+    private static func looksLikeMessaging(_ text: String) -> Bool {
+        ["slack", "telegram", "whatsapp", "discord", "messaging", "channel", "inbox", "dm", "chat app"]
+            .contains { text.contains($0) }
+    }
+
+    private static func suggestPluginName(for draft: PluginSkillDraft, existingIDs: [String]) -> String {
+        switch inferKind(from: draft) {
+        case .messagingConnector:
+            if let vendor = inferConnectorVendor(from: draft) {
+                return ConnectorPluginNaming.defaultPluginID(vendor: vendor, existingIDs: existingIDs)
+            }
+            return ConnectorPluginNaming.defaultPluginID(vendor: .slack, existingIDs: existingIDs)
+        case .customCapability:
+            let words = draft.goal
+                .lowercased()
+                .split { !$0.isLetter && !$0.isNumber }
+                .filter { $0.count > 2 }
+                .prefix(3)
+            let stem = words.isEmpty ? "custom-plugin" : String(words.joined(separator: "-"))
+            if !existingIDs.contains(stem) { return stem }
+            return "\(stem)-2"
+        }
+    }
+
+    private static func defaultTriggers(for draft: PluginSkillDraft) -> Set<PluginSkillDraft.Trigger> {
+        switch inferKind(from: draft) {
+        case .messagingConnector:
+            return [.messaging, .chat]
+        case .customCapability:
+            return [.chat]
+        }
+    }
+
+    private static func defaultExamples(for draft: PluginSkillDraft) -> [PluginSkillDraft.Example] {
+        switch inferKind(from: draft) {
+        case .messagingConnector:
+            let vendor = inferConnectorVendor(from: draft)?.displayName ?? "Slack"
+            return [
+                PluginSkillDraft.Example(
+                    userSays: "Show my \(vendor) channels",
+                    pluginDoes: "list conversations you can access as tabs in Messaging"
+                ),
+                PluginSkillDraft.Example(
+                    userSays: "Send “hello” to #general",
+                    pluginDoes: "post the message in that channel"
+                ),
+            ]
+        case .customCapability:
+            let snippet = draft.goal.trimmingCharacters(in: .whitespacesAndNewlines)
+            return [
+                PluginSkillDraft.Example(
+                    userSays: snippet.isEmpty ? "Do the thing I described" : snippet,
+                    pluginDoes: "run the guest program and return a clear result"
+                ),
+            ]
+        }
+    }
+}
+
+public enum PluginSkillDraftError: Error, LocalizedError {
+    case missingConnectorVendor
+    case invalidPluginName
+
+    public var errorDescription: String? {
+        switch self {
+        case .missingConnectorVendor:
+            return "Could not determine which messaging service this plugin targets."
+        case .invalidPluginName:
+            return "Choose a valid plugin name using letters, numbers, and hyphens."
+        }
+    }
+}
diff --git a/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/PromptResources.swift b/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/PromptResources.swift
index 4a24d9bc..cf769fa3 100644
--- a/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/PromptResources.swift
+++ b/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/PromptResources.swift
@@ -31,10 +31,6 @@ public enum PromptResources {
         try load(named: "files_extract_skill", from: resourceRoot)
     }
 
-    public static func scriptReviewerInstructions(from resourceRoot: URL? = nil) throws -> String {
-        try DerrickBundledText.load("script_reviewer_instructions.md", from: resourceRoot)
-    }
-
     public static func workerOverlay(from resourceRoot: URL? = nil) throws -> String {
         try DerrickBundledText.load("worker_overlay.md", from: resourceRoot)
     }
@@ -43,22 +39,22 @@ public enum PromptResources {
         try DerrickBundledText.load("user_facing_spawn_overlay.md", from: resourceRoot)
     }
 
-    /// Python guest contract wrapped for a model prompt.
+    /// Go guest contract wrapped for a model prompt.
     public static func guestSDKForModel(
         from resourceRoot: URL? = nil,
         spec: PluginSpec? = nil
     ) throws -> String {
         _ = resourceRoot
         return DerrickBundledText.formatCodeForModel(
-            try DerrickGuestPython.source(for: spec),
-            heading: "standalone Python guest contract",
-            language: "python"
+            try DerrickGuestGo.source(for: spec),
+            heading: "standalone Go guest contract",
+            language: "go"
         )
     }
 
     public static func guestSDKSource(from resourceRoot: URL? = nil) throws -> String {
         _ = resourceRoot
-        return try DerrickGuestPython.source()
+        return try DerrickGuestGo.source()
     }
 
     private static func load(named name: String, from resourceRoot: URL?, prefixTxt: String? = nil) throws -> String {
diff --git a/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/TurnProcessContextTypes.swift b/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/TurnProcessContextTypes.swift
index f5f57d3b..1350aed8 100644
--- a/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/TurnProcessContextTypes.swift
+++ b/packages/Structure/Sources/AppLayerServices/SharedAgentRuntime/TurnProcessContextTypes.swift
@@ -13,7 +13,7 @@ public struct ExecutionContextSlots: Sendable {
     public var networkAccessPrompt: TurnProcessContextTypes.NetworkPrompt?
     public var policyDecisionPrompt: TurnProcessContextTypes.PolicyDecisionPrompt?
     public var policyNoticePublisher: TurnProcessContextTypes.PolicyNoticePublisher?
-    /// When true, `web.crawl` may run synchronously (plugin factory turns).
+    /// When true, plugin factory creation is active for this turn.
     public var pluginFactoryCreationActive: Bool
 
     public init(
diff --git a/packages/Structure/Sources/Contract/Generated/ScriptExecContract.generated.swift b/packages/Structure/Sources/Contract/Generated/ScriptExecContract.generated.swift
new file mode 100644
index 00000000..e64934fc
--- /dev/null
+++ b/packages/Structure/Sources/Contract/Generated/ScriptExecContract.generated.swift
@@ -0,0 +1,13 @@
+// Automatically generated by scripts/generate-script-exec-contract.swift. DO NOT EDIT.
+
+/// SHA-256 of script_exec protocol JSON and schemas. `swift test` fails when this is stale.
+public enum ScriptExecContractFingerprint: Sendable {
+    public static let sha256 = "3a543a59f64b9c72a1fe94b8845af719740c17dfbc5ea81f5849c9554dcc8c89"
+    public static let sourceFiles: [String] = [
+        "schemas/script-exec-contract.schema.json",
+        "schemas/guest-runtime.schema.json",
+        "schemas/hop-event.schema.json",
+        "schemas/envelope-list.schema.json",
+        "contracts/script-exec-contract.json",
+    ]
+}
diff --git a/packages/Structure/Sources/Contract/GuestContract.swift b/packages/Structure/Sources/Contract/GuestContract.swift
index 0464da30..fdf034ad 100644
--- a/packages/Structure/Sources/Contract/GuestContract.swift
+++ b/packages/Structure/Sources/Contract/GuestContract.swift
@@ -11,6 +11,11 @@ public enum GuestContract: Sendable {
         case connectorParams = "connector-params.schema.json"
         case connectorResultEmit = "connector-result-emit.schema.json"
         case connectorVendor = "connector-vendor.schema.json"
+        case guestRuntime = "guest-runtime.schema.json"
+        case workerProduct = "worker-product.schema.json"
+        case webCrawlerResult = "web-crawler-result.schema.json"
+        case fileExtractorResult = "file-extractor-result.schema.json"
+        case scriptExecContract = "script-exec-contract.schema.json"
     }
 
     public static func loadSchemaText(_ schema: Schema) throws -> String {
diff --git a/packages/Structure/Sources/Contract/GuestContractValidation.swift b/packages/Structure/Sources/Contract/GuestContractValidation.swift
index 83fcb430..1da6e55f 100644
--- a/packages/Structure/Sources/Contract/GuestContractValidation.swift
+++ b/packages/Structure/Sources/Contract/GuestContractValidation.swift
@@ -9,4 +9,12 @@ public enum GuestContractValidation: Sendable {
     public static func validateHopEventJSON(_ data: Data) throws {
         try GuestContract.validate(json: data, against: .hopEvent)
     }
+
+    public static func validateWebCrawlerResultJSON(_ data: Data) throws {
+        try GuestContract.validate(json: data, against: .webCrawlerResult)
+    }
+
+    public static func validateFileExtractorResultJSON(_ data: Data) throws {
+        try GuestContract.validate(json: data, against: .fileExtractorResult)
+    }
 }
diff --git a/packages/Structure/Sources/Contract/Resources/contracts/script-exec-contract.json b/packages/Structure/Sources/Contract/Resources/contracts/script-exec-contract.json
new file mode 100644
index 00000000..99f30c60
--- /dev/null
+++ b/packages/Structure/Sources/Contract/Resources/contracts/script-exec-contract.json
@@ -0,0 +1,173 @@
+{
+  "version": 1,
+  "runtime": {
+    "language": "go",
+    "package": "main",
+    "binary": "/tmp/guest",
+    "stdlib_only": true,
+    "forbidden_imports": ["net/http", "net", "os/exec"],
+    "allowed_os_usage": ["os.Stdin", "os.Stdout"],
+    "example_go": "package main\n\nimport (\n\t\"encoding/json\"\n\t\"os\"\n)\n\nfunc main() {\n\tvar event map[string]any\n\tif err := json.NewDecoder(os.Stdin).Decode(&event); err != nil {\n\t\treturn\n\t}\n\temit([]map[string]any{{\"verb\": \"result.emit\", \"title\": \"Result\", \"summary\": \"done\"}})\n}\n\nfunc emit(envelopes []map[string]any) {\n\tenc := json.NewEncoder(os.Stdout)\n\tenc.SetEscapeHTML(false)\n\t_ = enc.Encode(envelopes)\n}"
+  },
+  "io": {
+    "stdin_schema": "hop-event.schema.json",
+    "stdout_schema": "envelope-list.schema.json",
+    "guest_runtime_schema": "guest-runtime.schema.json"
+  },
+  "workflow": {
+    "first_hop_verbs": ["http.request"],
+    "http_results_event_kind": "http_results",
+    "terminal_verbs": ["result.emit", "message.post"],
+    "match_http_by": "request_id",
+    "http_results_accumulate": true,
+    "post_body_field": "json"
+  },
+  "output": {
+    "fields": {
+      "content": {
+        "purpose": "parsed plain-text summaries from fetched HTML, XML, or RSS",
+        "host_strips_incidental_markup": true
+      },
+      "summary": {
+        "purpose": "short plain-text headline or one-line result",
+        "host_strips_incidental_markup": true
+      },
+      "html": {
+        "purpose": "only when the user explicitly requested HTML",
+        "host_allowlist_sanitizes": true
+      },
+      "markdown": {
+        "purpose": "intentional Markdown formatting only",
+        "prefer_content_for_extracted_text": true
+      }
+    },
+    "forbidden_patterns": ["repr(http_results)"],
+    "raw_body_in_content_requires_explicit_user_request": true
+  },
+  "agent": {
+    "prefer_direct_urls_over_serp_html": true,
+    "retry_with_different_urls_on_empty_fetch": true,
+    "max_correction_attempts_after_block": 1
+  },
+  "review": {
+    "fail_fast": true,
+    "response_schema": {
+      "alignedWithRequest": "boolean",
+      "confidence": "number 0.0-1.0",
+      "suggestedAction": "allow|deny",
+      "concerns": "string[]",
+      "summary": "string"
+    },
+    "checks": [
+      {
+        "id": "intent_alignment",
+        "order": 1,
+        "description": "Script, description, reason, and user prompt are consistent.",
+        "notes": [
+          "Derrick has a job scheduler (jobs_create, run_after_seconds, cron). Timing is applied by JobService before this script runs.",
+          "The script must do the work immediately when invoked.",
+          "Words like delayed, scheduled, in 7 seconds, later, or run_after refer to the scheduler, not sleep inside the script.",
+          "Do not deny a script that performs the requested work just because it has no delay."
+        ]
+      },
+      {
+        "id": "no_secret_literals",
+        "order": 2,
+        "description": "No tokens, API keys, passwords, or other secret literals in the source."
+      },
+      {
+        "id": "terminal_result_not_fetch_only",
+        "order": 3,
+        "description": "The script implements the requested terminal result, not just the fetch.",
+        "notes": [
+          "For summarize, list, inspect, or extract requests, the http_results branch must parse the response body and emit the requested data.",
+          "Do not allow repr(http_results), a fetch-only confirmation, or an entire raw body copied to content unless the user explicitly requested the raw source.",
+          "If raw HTML is requested, html is allowed because the host sanitizes it before rendering."
+        ]
+      },
+      {
+        "id": "untrusted_remote_content",
+        "order": 4,
+        "description": "Fetched HTML or XML is untrusted input; output must use envelope-list output fields correctly.",
+        "notes": [
+          "Prefer content or summary for extracted plain-text lists and headlines.",
+          "Use html only when the user explicitly asked for HTML.",
+          "Use markdown only for intentional Markdown formatting.",
+          "Approve scripts that parse RSS, XML, or HTML and emit normalized plain text in content or summary.",
+          "Do not deny solely because the source was XML or HTML or because the guest does not re-validate http or https on plain-text lines."
+        ]
+      }
+    ],
+    "do_not_deny_for": [
+      "go_style",
+      "envelope_construction",
+      "destination_urls",
+      "absence_of_dependencies"
+    ],
+    "enforced_elsewhere": [
+      "static_go_verifier_enforces_forbidden_imports",
+      "guest_has_no_network_host_performs_http",
+      "host_applies_ssrf_on_http"
+    ]
+  },
+  "rules": {
+    "guest_has_no_network": true,
+    "host_performs_http": true,
+    "host_applies_ssrf": true,
+    "static_verifier_enforces_imports": true,
+    "scheduler_timing_not_in_script": true,
+    "deterministic_output_required": true,
+    "stable_sort_and_dedupe_collections": true,
+    "no_time_random_uuid_for_visible_output": true,
+    "match_http_results_by_request_id": true
+  },
+  "plugin_factory": {
+    "manifest": {
+      "host_creates_manifest": true,
+      "do_not_return_manifest_json": true,
+      "agent_plugin_schema": "Agent Plugin 1.0",
+      "entrypoint": "./app.derrick/plugin.go",
+      "plugin_id_allowed_chars": "lowercase letters, numbers, hyphens, dots",
+      "plugin_id_forbidden_chars": ["underscore"],
+      "roles": ["connector", "standard"],
+      "connector_messaging_ops": ["send_message", "poll_inbox", "sync_threads"],
+      "secret_kinds": ["username", "password", "token", "api_key"],
+      "never_embed_credentials_in_go_source": true,
+      "host_lists_connectors_under_messaging": true
+    },
+    "builder": {
+      "response_keys": [
+        "plugin_id",
+        "version",
+        "description",
+        "go_source",
+        "test_input_json",
+        "skill_files",
+        "secrets",
+        "role",
+        "messaging_ops"
+      ],
+      "skill_files_path_pattern": "skills/<name>/SKILL.md",
+      "empty_skill_files_when_unused": true,
+      "test_input_is_serialized_json_object": true,
+      "test_input_must_not_be_empty": true,
+      "test_input_exercises_terminal_result": true,
+      "connector_test_input_uses_hops_array": true,
+      "connector_parse_json_http_results_when_vendor_returns_json": true
+    },
+    "review": {
+      "compilation_success_not_approval": true,
+      "response_schema": {
+        "decision": "approved|rejected",
+        "summary": "string",
+        "findings": "[{severity: info|warning|blocking, category: alignment|safety|correctness|privacy|supplyChain, message: string}]"
+      },
+      "reject_non_go_source": true,
+      "reject_raw_network_outside_http_request_envelopes": true,
+      "reject_missing_stdin_read": true,
+      "source_derived_titles_may_be_fragments": true,
+      "reject_unsupported_direct_test_claims": true,
+      "connector_rules_document": "connector-contract.json"
+    }
+  }
+}
diff --git a/packages/Structure/Sources/Contract/Resources/schemas/file-extractor-result.schema.json b/packages/Structure/Sources/Contract/Resources/schemas/file-extractor-result.schema.json
new file mode 100644
index 00000000..c4e12bc4
--- /dev/null
+++ b/packages/Structure/Sources/Contract/Resources/schemas/file-extractor-result.schema.json
@@ -0,0 +1,7 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/file-extractor-result.json",
+  "title": "File extractor worker stdout",
+  "description": "JSON object written to stdout by derrick-file-extractor.",
+  "$ref": "worker-product.schema.json#/$defs/file_extractor_result"
+}
diff --git a/packages/Structure/Sources/Contract/Resources/schemas/guest-runtime.schema.json b/packages/Structure/Sources/Contract/Resources/schemas/guest-runtime.schema.json
new file mode 100644
index 00000000..03f4f622
--- /dev/null
+++ b/packages/Structure/Sources/Contract/Resources/schemas/guest-runtime.schema.json
@@ -0,0 +1,29 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/guest-runtime.json",
+  "title": "Derrick offline guest runtime",
+  "description": "Canonical I/O contract for script_exec and plugin.invoke guests. Trusted worker stdout (crawler, extractor) is defined in worker-product.schema.json. Swift host and Go workers must match these schemas.",
+  "type": "object",
+  "required": ["language", "stdin", "stdout"],
+  "additionalProperties": false,
+  "properties": {
+    "language": {
+      "type": "string",
+      "const": "go",
+      "description": "Guest implementation language."
+    },
+    "stdin": {
+      "description": "One hop event JSON object read from standard input.",
+      "$ref": "hop-event.schema.json"
+    },
+    "stdout": {
+      "description": "Envelope list JSON array written to standard output.",
+      "$ref": "envelope-list.schema.json"
+    },
+    "binary": {
+      "type": "string",
+      "const": "/tmp/guest",
+      "description": "Linux guest binary path inside the worker container."
+    }
+  }
+}
diff --git a/packages/Structure/Sources/Contract/Resources/schemas/script-exec-contract.schema.json b/packages/Structure/Sources/Contract/Resources/schemas/script-exec-contract.schema.json
new file mode 100644
index 00000000..2e369012
--- /dev/null
+++ b/packages/Structure/Sources/Contract/Resources/schemas/script-exec-contract.schema.json
@@ -0,0 +1,346 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/script-exec-contract.json",
+  "title": "Derrick script_exec protocol document",
+  "description": "Canonical guest runtime, workflow, output, agent, and reviewer rules for script_exec and offline Go guests.",
+  "type": "object",
+  "required": [
+    "version",
+    "runtime",
+    "io",
+    "workflow",
+    "output",
+    "agent",
+    "review",
+    "rules",
+    "plugin_factory"
+  ],
+  "additionalProperties": false,
+  "properties": {
+    "version": { "type": "integer", "const": 1 },
+    "runtime": { "$ref": "#/$defs/runtime" },
+    "io": { "$ref": "#/$defs/io" },
+    "workflow": { "$ref": "#/$defs/workflow" },
+    "output": { "$ref": "#/$defs/output" },
+    "agent": { "$ref": "#/$defs/agent" },
+    "review": { "$ref": "#/$defs/review" },
+    "rules": { "$ref": "#/$defs/rules" },
+    "plugin_factory": { "$ref": "#/$defs/plugin_factory" }
+  },
+  "$defs": {
+    "runtime": {
+      "type": "object",
+      "required": [
+        "language",
+        "package",
+        "binary",
+        "stdlib_only",
+        "forbidden_imports",
+        "allowed_os_usage",
+        "example_go"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "language": { "type": "string", "const": "go" },
+        "package": { "type": "string", "const": "main" },
+        "binary": { "type": "string", "const": "/tmp/guest" },
+        "stdlib_only": { "type": "boolean" },
+        "forbidden_imports": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "allowed_os_usage": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "example_go": { "type": "string", "minLength": 1 }
+      }
+    },
+    "io": {
+      "type": "object",
+      "required": ["stdin_schema", "stdout_schema", "guest_runtime_schema"],
+      "additionalProperties": false,
+      "properties": {
+        "stdin_schema": { "type": "string", "const": "hop-event.schema.json" },
+        "stdout_schema": { "type": "string", "const": "envelope-list.schema.json" },
+        "guest_runtime_schema": { "type": "string", "const": "guest-runtime.schema.json" }
+      }
+    },
+    "workflow": {
+      "type": "object",
+      "required": [
+        "first_hop_verbs",
+        "http_results_event_kind",
+        "terminal_verbs",
+        "match_http_by",
+        "http_results_accumulate",
+        "post_body_field"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "first_hop_verbs": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "http_results_event_kind": { "type": "string" },
+        "terminal_verbs": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "match_http_by": { "type": "string", "const": "request_id" },
+        "http_results_accumulate": { "type": "boolean" },
+        "post_body_field": { "type": "string", "const": "json" }
+      }
+    },
+    "output": {
+      "type": "object",
+      "required": ["fields", "forbidden_patterns", "raw_body_in_content_requires_explicit_user_request"],
+      "additionalProperties": false,
+      "properties": {
+        "fields": {
+          "type": "object",
+          "required": ["content", "summary", "html", "markdown"],
+          "additionalProperties": false,
+          "properties": {
+            "content": { "$ref": "#/$defs/output_field" },
+            "summary": { "$ref": "#/$defs/output_field" },
+            "html": { "$ref": "#/$defs/output_field" },
+            "markdown": { "$ref": "#/$defs/output_field" }
+          }
+        },
+        "forbidden_patterns": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "raw_body_in_content_requires_explicit_user_request": { "type": "boolean" }
+      }
+    },
+    "output_field": {
+      "type": "object",
+      "required": ["purpose"],
+      "additionalProperties": true,
+      "properties": {
+        "purpose": { "type": "string" },
+        "host_strips_incidental_markup": { "type": "boolean" },
+        "host_allowlist_sanitizes": { "type": "boolean" },
+        "prefer_content_for_extracted_text": { "type": "boolean" }
+      }
+    },
+    "agent": {
+      "type": "object",
+      "required": [
+        "prefer_direct_urls_over_serp_html",
+        "retry_with_different_urls_on_empty_fetch",
+        "max_correction_attempts_after_block"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "prefer_direct_urls_over_serp_html": { "type": "boolean" },
+        "retry_with_different_urls_on_empty_fetch": { "type": "boolean" },
+        "max_correction_attempts_after_block": { "type": "integer", "minimum": 0 }
+      }
+    },
+    "review": {
+      "type": "object",
+      "required": [
+        "fail_fast",
+        "response_schema",
+        "checks",
+        "do_not_deny_for",
+        "enforced_elsewhere"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "fail_fast": { "type": "boolean" },
+        "response_schema": {
+          "type": "object",
+          "required": [
+            "alignedWithRequest",
+            "confidence",
+            "suggestedAction",
+            "concerns",
+            "summary"
+          ],
+          "additionalProperties": false,
+          "properties": {
+            "alignedWithRequest": { "type": "string" },
+            "confidence": { "type": "string" },
+            "suggestedAction": { "type": "string" },
+            "concerns": { "type": "string" },
+            "summary": { "type": "string" }
+          }
+        },
+        "checks": {
+          "type": "array",
+          "minItems": 1,
+          "items": { "$ref": "#/$defs/review_check" }
+        },
+        "do_not_deny_for": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "enforced_elsewhere": {
+          "type": "array",
+          "items": { "type": "string" }
+        }
+      }
+    },
+    "review_check": {
+      "type": "object",
+      "required": ["id", "order", "description"],
+      "additionalProperties": false,
+      "properties": {
+        "id": { "type": "string" },
+        "order": { "type": "integer", "minimum": 1 },
+        "description": { "type": "string" },
+        "notes": {
+          "type": "array",
+          "items": { "type": "string" }
+        }
+      }
+    },
+    "rules": {
+      "type": "object",
+      "required": [
+        "guest_has_no_network",
+        "host_performs_http",
+        "host_applies_ssrf",
+        "static_verifier_enforces_imports",
+        "scheduler_timing_not_in_script",
+        "deterministic_output_required",
+        "stable_sort_and_dedupe_collections",
+        "no_time_random_uuid_for_visible_output",
+        "match_http_results_by_request_id"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "guest_has_no_network": { "type": "boolean" },
+        "host_performs_http": { "type": "boolean" },
+        "host_applies_ssrf": { "type": "boolean" },
+        "static_verifier_enforces_imports": { "type": "boolean" },
+        "scheduler_timing_not_in_script": { "type": "boolean" },
+        "deterministic_output_required": { "type": "boolean" },
+        "stable_sort_and_dedupe_collections": { "type": "boolean" },
+        "no_time_random_uuid_for_visible_output": { "type": "boolean" },
+        "match_http_results_by_request_id": { "type": "boolean" }
+      }
+    },
+    "plugin_factory": {
+      "type": "object",
+      "required": ["manifest", "builder", "review"],
+      "additionalProperties": false,
+      "properties": {
+        "manifest": { "$ref": "#/$defs/plugin_factory_manifest" },
+        "builder": { "$ref": "#/$defs/plugin_factory_builder" },
+        "review": { "$ref": "#/$defs/plugin_factory_review" }
+      }
+    },
+    "plugin_factory_manifest": {
+      "type": "object",
+      "required": [
+        "host_creates_manifest",
+        "do_not_return_manifest_json",
+        "agent_plugin_schema",
+        "entrypoint",
+        "plugin_id_allowed_chars",
+        "plugin_id_forbidden_chars",
+        "roles",
+        "connector_messaging_ops",
+        "secret_kinds",
+        "never_embed_credentials_in_go_source",
+        "host_lists_connectors_under_messaging"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "host_creates_manifest": { "type": "boolean" },
+        "do_not_return_manifest_json": { "type": "boolean" },
+        "agent_plugin_schema": { "type": "string" },
+        "entrypoint": { "type": "string" },
+        "plugin_id_allowed_chars": { "type": "string" },
+        "plugin_id_forbidden_chars": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "roles": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "connector_messaging_ops": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "secret_kinds": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "never_embed_credentials_in_go_source": { "type": "boolean" },
+        "host_lists_connectors_under_messaging": { "type": "boolean" }
+      }
+    },
+    "plugin_factory_builder": {
+      "type": "object",
+      "required": [
+        "response_keys",
+        "skill_files_path_pattern",
+        "empty_skill_files_when_unused",
+        "test_input_is_serialized_json_object",
+        "test_input_must_not_be_empty",
+        "test_input_exercises_terminal_result",
+        "connector_test_input_uses_hops_array",
+        "connector_parse_json_http_results_when_vendor_returns_json"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "response_keys": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "skill_files_path_pattern": { "type": "string" },
+        "empty_skill_files_when_unused": { "type": "boolean" },
+        "test_input_is_serialized_json_object": { "type": "boolean" },
+        "test_input_must_not_be_empty": { "type": "boolean" },
+        "test_input_exercises_terminal_result": { "type": "boolean" },
+        "connector_test_input_uses_hops_array": { "type": "boolean" },
+        "connector_parse_json_http_results_when_vendor_returns_json": { "type": "boolean" }
+      }
+    },
+    "plugin_factory_review": {
+      "type": "object",
+      "required": [
+        "compilation_success_not_approval",
+        "response_schema",
+        "reject_non_go_source",
+        "reject_raw_network_outside_http_request_envelopes",
+        "reject_missing_stdin_read",
+        "source_derived_titles_may_be_fragments",
+        "reject_unsupported_direct_test_claims",
+        "connector_rules_document"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "compilation_success_not_approval": { "type": "boolean" },
+        "response_schema": {
+          "type": "object",
+          "required": ["decision", "summary", "findings"],
+          "additionalProperties": false,
+          "properties": {
+            "decision": { "type": "string" },
+            "summary": { "type": "string" },
+            "findings": { "type": "string" }
+          }
+        },
+        "reject_non_go_source": { "type": "boolean" },
+        "reject_raw_network_outside_http_request_envelopes": { "type": "boolean" },
+        "reject_missing_stdin_read": { "type": "boolean" },
+        "source_derived_titles_may_be_fragments": { "type": "boolean" },
+        "reject_unsupported_direct_test_claims": { "type": "boolean" },
+        "connector_rules_document": { "type": "string" }
+      }
+    }
+  }
+}
diff --git a/packages/Structure/Sources/Contract/Resources/schemas/web-crawler-result.schema.json b/packages/Structure/Sources/Contract/Resources/schemas/web-crawler-result.schema.json
new file mode 100644
index 00000000..9af39755
--- /dev/null
+++ b/packages/Structure/Sources/Contract/Resources/schemas/web-crawler-result.schema.json
@@ -0,0 +1,7 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/web-crawler-result.json",
+  "title": "Web crawler worker stdout",
+  "description": "JSON object written to stdout by derrick-web-crawler.",
+  "$ref": "worker-product.schema.json#/$defs/web_crawler_result"
+}
diff --git a/packages/Structure/Sources/Contract/Resources/schemas/worker-product.schema.json b/packages/Structure/Sources/Contract/Resources/schemas/worker-product.schema.json
new file mode 100644
index 00000000..874f6bfb
--- /dev/null
+++ b/packages/Structure/Sources/Contract/Resources/schemas/worker-product.schema.json
@@ -0,0 +1,97 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/worker-product.json",
+  "title": "Derrick trusted worker product contracts",
+  "description": "Shared stdout JSON contracts for prebuilt Go worker binaries (web crawler and file extractor). Swift host and Go workers must match these schemas.",
+  "$defs": {
+    "string_list": {
+      "type": "array",
+      "items": { "type": "string" }
+    },
+    "web_crawler_stop_reason": {
+      "type": "string",
+      "enum": [
+        "completed",
+        "max_pages",
+        "max_depth",
+        "timeout",
+        "total_bytes",
+        "queue_limit",
+        "cancelled",
+        "blocked"
+      ]
+    },
+    "web_crawler_page": {
+      "type": "object",
+      "required": ["url", "depth", "status_code", "title", "text", "links_found"],
+      "additionalProperties": false,
+      "properties": {
+        "url": { "type": "string" },
+        "depth": { "type": "integer" },
+        "status_code": { "type": "integer" },
+        "content_type": { "type": "string" },
+        "title": { "type": "string" },
+        "text": { "type": "string" },
+        "links_found": { "type": "integer" }
+      }
+    },
+    "web_crawler_result": {
+      "type": "object",
+      "required": [
+        "ok",
+        "start_url",
+        "pages",
+        "stop_reason",
+        "requests_made",
+        "bytes_read",
+        "truncated",
+        "diagnostics"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "ok": { "type": "boolean" },
+        "start_url": { "type": "string" },
+        "pages": {
+          "type": "array",
+          "items": { "$ref": "#/$defs/web_crawler_page" }
+        },
+        "stop_reason": { "$ref": "#/$defs/web_crawler_stop_reason" },
+        "requests_made": { "type": "integer" },
+        "bytes_read": { "type": "integer" },
+        "truncated": { "type": "boolean" },
+        "diagnostics": { "$ref": "#/$defs/string_list" }
+      }
+    },
+    "file_extractor_operation": {
+      "type": "string",
+      "enum": ["extract", "convert"]
+    },
+    "file_extractor_file_result": {
+      "type": "object",
+      "required": ["input_name", "kind", "byte_count"],
+      "additionalProperties": false,
+      "properties": {
+        "input_name": { "type": "string" },
+        "output_name": { "type": "string" },
+        "kind": { "type": "string" },
+        "byte_count": { "type": "integer" },
+        "preview": { "type": "string" },
+        "error": { "type": "string" }
+      }
+    },
+    "file_extractor_result": {
+      "type": "object",
+      "required": ["ok", "operation", "files", "diagnostics"],
+      "additionalProperties": false,
+      "properties": {
+        "ok": { "type": "boolean" },
+        "operation": { "$ref": "#/$defs/file_extractor_operation" },
+        "files": {
+          "type": "array",
+          "items": { "$ref": "#/$defs/file_extractor_file_result" }
+        },
+        "diagnostics": { "$ref": "#/$defs/string_list" }
+      }
+    }
+  }
+}
diff --git a/packages/Structure/Sources/Contract/ScriptExecContractDocument.swift b/packages/Structure/Sources/Contract/ScriptExecContractDocument.swift
new file mode 100644
index 00000000..83a308d8
--- /dev/null
+++ b/packages/Structure/Sources/Contract/ScriptExecContractDocument.swift
@@ -0,0 +1,250 @@
+import Foundation
+
+/// Canonical Derrick script_exec protocol decoded from `script-exec-contract.json`.
+public struct ScriptExecContractDocument: Codable, Sendable, Hashable {
+    public var version: Int
+    public var runtime: ScriptExecRuntimeSpec
+    public var io: ScriptExecIOSpec
+    public var workflow: ScriptExecWorkflowSpec
+    public var output: ScriptExecOutputSpec
+    public var agent: ScriptExecAgentSpec
+    public var review: ScriptExecReviewSpec
+    public var rules: ScriptExecProtocolRules
+    public var pluginFactory: ScriptExecPluginFactorySpec
+
+    enum CodingKeys: String, CodingKey {
+        case version, runtime, io, workflow, output, agent, review, rules
+        case pluginFactory = "plugin_factory"
+    }
+}
+
+public struct ScriptExecRuntimeSpec: Codable, Sendable, Hashable {
+    public var language: String
+    public var package: String
+    public var binary: String
+    public var stdlibOnly: Bool
+    public var forbiddenImports: [String]
+    public var allowedOSUsage: [String]
+    public var exampleGo: String
+
+    enum CodingKeys: String, CodingKey {
+        case language, package, binary
+        case stdlibOnly = "stdlib_only"
+        case forbiddenImports = "forbidden_imports"
+        case allowedOSUsage = "allowed_os_usage"
+        case exampleGo = "example_go"
+    }
+}
+
+public struct ScriptExecIOSpec: Codable, Sendable, Hashable {
+    public var stdinSchema: String
+    public var stdoutSchema: String
+    public var guestRuntimeSchema: String
+
+    enum CodingKeys: String, CodingKey {
+        case stdinSchema = "stdin_schema"
+        case stdoutSchema = "stdout_schema"
+        case guestRuntimeSchema = "guest_runtime_schema"
+    }
+}
+
+public struct ScriptExecWorkflowSpec: Codable, Sendable, Hashable {
+    public var firstHopVerbs: [String]
+    public var httpResultsEventKind: String
+    public var terminalVerbs: [String]
+    public var matchHTTPBy: String
+    public var httpResultsAccumulate: Bool
+    public var postBodyField: String
+
+    enum CodingKeys: String, CodingKey {
+        case firstHopVerbs = "first_hop_verbs"
+        case httpResultsEventKind = "http_results_event_kind"
+        case terminalVerbs = "terminal_verbs"
+        case matchHTTPBy = "match_http_by"
+        case httpResultsAccumulate = "http_results_accumulate"
+        case postBodyField = "post_body_field"
+    }
+}
+
+public struct ScriptExecOutputSpec: Codable, Sendable, Hashable {
+    public var fields: [String: ScriptExecOutputFieldSpec]
+    public var forbiddenPatterns: [String]
+    public var rawBodyInContentRequiresExplicitUserRequest: Bool
+
+    enum CodingKeys: String, CodingKey {
+        case fields
+        case forbiddenPatterns = "forbidden_patterns"
+        case rawBodyInContentRequiresExplicitUserRequest =
+            "raw_body_in_content_requires_explicit_user_request"
+    }
+}
+
+public struct ScriptExecOutputFieldSpec: Codable, Sendable, Hashable {
+    public var purpose: String
+    public var hostStripsIncidentalMarkup: Bool?
+    public var hostAllowlistSanitizes: Bool?
+    public var preferContentForExtractedText: Bool?
+
+    enum CodingKeys: String, CodingKey {
+        case purpose
+        case hostStripsIncidentalMarkup = "host_strips_incidental_markup"
+        case hostAllowlistSanitizes = "host_allowlist_sanitizes"
+        case preferContentForExtractedText = "prefer_content_for_extracted_text"
+    }
+}
+
+public struct ScriptExecAgentSpec: Codable, Sendable, Hashable {
+    public var preferDirectURLsOverSERPHTML: Bool
+    public var retryWithDifferentURLsOnEmptyFetch: Bool
+    public var maxCorrectionAttemptsAfterBlock: Int
+
+    enum CodingKeys: String, CodingKey {
+        case preferDirectURLsOverSERPHTML = "prefer_direct_urls_over_serp_html"
+        case retryWithDifferentURLsOnEmptyFetch = "retry_with_different_urls_on_empty_fetch"
+        case maxCorrectionAttemptsAfterBlock = "max_correction_attempts_after_block"
+    }
+}
+
+public struct ScriptExecReviewSpec: Codable, Sendable, Hashable {
+    public var failFast: Bool
+    public var responseSchema: [String: String]
+    public var checks: [ScriptExecReviewCheck]
+    public var doNotDenyFor: [String]
+    public var enforcedElsewhere: [String]
+
+    enum CodingKeys: String, CodingKey {
+        case failFast = "fail_fast"
+        case responseSchema = "response_schema"
+        case checks
+        case doNotDenyFor = "do_not_deny_for"
+        case enforcedElsewhere = "enforced_elsewhere"
+    }
+}
+
+public struct ScriptExecReviewCheck: Codable, Sendable, Hashable {
+    public var id: String
+    public var order: Int
+    public var description: String
+    public var notes: [String]?
+}
+
+public struct ScriptExecProtocolRules: Codable, Sendable, Hashable {
+    public var guestHasNoNetwork: Bool
+    public var hostPerformsHTTP: Bool
+    public var hostAppliesSSRF: Bool
+    public var staticVerifierEnforcesImports: Bool
+    public var schedulerTimingNotInScript: Bool
+    public var deterministicOutputRequired: Bool
+    public var stableSortAndDedupeCollections: Bool
+    public var noTimeRandomUUIDForVisibleOutput: Bool
+    public var matchHTTPResultsByRequestID: Bool
+
+    enum CodingKeys: String, CodingKey {
+        case guestHasNoNetwork = "guest_has_no_network"
+        case hostPerformsHTTP = "host_performs_http"
+        case hostAppliesSSRF = "host_applies_ssrf"
+        case staticVerifierEnforcesImports = "static_verifier_enforces_imports"
+        case schedulerTimingNotInScript = "scheduler_timing_not_in_script"
+        case deterministicOutputRequired = "deterministic_output_required"
+        case stableSortAndDedupeCollections = "stable_sort_and_dedupe_collections"
+        case noTimeRandomUUIDForVisibleOutput = "no_time_random_uuid_for_visible_output"
+        case matchHTTPResultsByRequestID = "match_http_results_by_request_id"
+    }
+}
+
+public struct ScriptExecPluginFactorySpec: Codable, Sendable, Hashable {
+    public var manifest: ScriptExecPluginFactoryManifestSpec
+    public var builder: ScriptExecPluginFactoryBuilderSpec
+    public var review: ScriptExecPluginFactoryReviewSpec
+}
+
+public struct ScriptExecPluginFactoryManifestSpec: Codable, Sendable, Hashable {
+    public var hostCreatesManifest: Bool
+    public var doNotReturnManifestJSON: Bool
+    public var agentPluginSchema: String
+    public var entrypoint: String
+    public var pluginIDAllowedChars: String
+    public var pluginIDForbiddenChars: [String]
+    public var roles: [String]
+    public var connectorMessagingOps: [String]
+    public var secretKinds: [String]
+    public var neverEmbedCredentialsInGoSource: Bool
+    public var hostListsConnectorsUnderMessaging: Bool
+
+    enum CodingKeys: String, CodingKey {
+        case hostCreatesManifest = "host_creates_manifest"
+        case doNotReturnManifestJSON = "do_not_return_manifest_json"
+        case agentPluginSchema = "agent_plugin_schema"
+        case entrypoint
+        case pluginIDAllowedChars = "plugin_id_allowed_chars"
+        case pluginIDForbiddenChars = "plugin_id_forbidden_chars"
+        case roles
+        case connectorMessagingOps = "connector_messaging_ops"
+        case secretKinds = "secret_kinds"
+        case neverEmbedCredentialsInGoSource = "never_embed_credentials_in_go_source"
+        case hostListsConnectorsUnderMessaging = "host_lists_connectors_under_messaging"
+    }
+}
+
+public struct ScriptExecPluginFactoryBuilderSpec: Codable, Sendable, Hashable {
+    public var responseKeys: [String]
+    public var skillFilesPathPattern: String
+    public var emptySkillFilesWhenUnused: Bool
+    public var testInputIsSerializedJSONObject: Bool
+    public var testInputMustNotBeEmpty: Bool
+    public var testInputExercisesTerminalResult: Bool
+    public var connectorTestInputUsesHopsArray: Bool
+    public var connectorParseJSONHTTPResultsWhenVendorReturnsJSON: Bool
+
+    enum CodingKeys: String, CodingKey {
+        case responseKeys = "response_keys"
+        case skillFilesPathPattern = "skill_files_path_pattern"
+        case emptySkillFilesWhenUnused = "empty_skill_files_when_unused"
+        case testInputIsSerializedJSONObject = "test_input_is_serialized_json_object"
+        case testInputMustNotBeEmpty = "test_input_must_not_be_empty"
+        case testInputExercisesTerminalResult = "test_input_exercises_terminal_result"
+        case connectorTestInputUsesHopsArray = "connector_test_input_uses_hops_array"
+        case connectorParseJSONHTTPResultsWhenVendorReturnsJSON =
+            "connector_parse_json_http_results_when_vendor_returns_json"
+    }
+}
+
+public struct ScriptExecPluginFactoryReviewSpec: Codable, Sendable, Hashable {
+    public var compilationSuccessNotApproval: Bool
+    public var responseSchema: [String: String]
+    public var rejectNonGoSource: Bool
+    public var rejectRawNetworkOutsideHTTPRequestEnvelopes: Bool
+    public var rejectMissingStdinRead: Bool
+    public var sourceDerivedTitlesMayBeFragments: Bool
+    public var rejectUnsupportedDirectTestClaims: Bool
+    public var connectorRulesDocument: String
+
+    enum CodingKeys: String, CodingKey {
+        case compilationSuccessNotApproval = "compilation_success_not_approval"
+        case responseSchema = "response_schema"
+        case rejectNonGoSource = "reject_non_go_source"
+        case rejectRawNetworkOutsideHTTPRequestEnvelopes =
+            "reject_raw_network_outside_http_request_envelopes"
+        case rejectMissingStdinRead = "reject_missing_stdin_read"
+        case sourceDerivedTitlesMayBeFragments = "source_derived_titles_may_be_fragments"
+        case rejectUnsupportedDirectTestClaims = "reject_unsupported_direct_test_claims"
+        case connectorRulesDocument = "connector_rules_document"
+    }
+}
+
+public enum ScriptExecContractError: Error, Equatable, LocalizedError, Sendable {
+    case missingResource(String)
+    case invalidJSON(String)
+    case integrityFailed(String)
+
+    public var errorDescription: String? {
+        switch self {
+        case .missingResource(let name):
+            return "Missing bundled script_exec contract resource \(name)."
+        case .invalidJSON(let name):
+            return "Script_exec contract resource \(name) is not valid JSON."
+        case .integrityFailed(let detail):
+            return "Script_exec contract JSON failed schema checks: \(detail)"
+        }
+    }
+}
diff --git a/packages/Structure/Sources/Contract/ScriptExecContractIntegrity.swift b/packages/Structure/Sources/Contract/ScriptExecContractIntegrity.swift
new file mode 100644
index 00000000..81face78
--- /dev/null
+++ b/packages/Structure/Sources/Contract/ScriptExecContractIntegrity.swift
@@ -0,0 +1,93 @@
+import Foundation
+
+/// Host checks that the bundled script_exec JSON still matches its schema and wire schemas.
+public enum ScriptExecContractIntegrity: Sendable {
+    public static func validateBundledGraph() throws {
+        let contractData = try ScriptExecContractStore.resourceData(
+            name: ScriptExecContractStore.protocolResource,
+            subdirectory: "contracts"
+        )
+        let contractJSON: [String: Any]
+        do {
+            contractJSON = try JSONSchema.object(
+                from: contractData,
+                name: ScriptExecContractStore.protocolResource
+            )
+        } catch {
+            throw ScriptExecContractError.invalidJSON(ScriptExecContractStore.protocolResource)
+        }
+        try validateAgainstSchema(contractJSON, schema: .scriptExecContract)
+        try validateWireSchemaRefs(contractJSON)
+        try validateOutputFields(contractJSON)
+        try validateReviewChecks(contractJSON)
+    }
+
+    private static func validateAgainstSchema(_ instance: Any, schema: GuestContract.Schema) throws {
+        do {
+            try GuestContract.validate(instance, against: schema)
+        } catch let error as GuestContractError {
+            throw ScriptExecContractError.integrityFailed(error.localizedDescription)
+        }
+    }
+
+    private static func validateWireSchemaRefs(_ contract: [String: Any]) throws {
+        guard let io = contract["io"] as? [String: Any] else { return }
+        for key in ["stdin_schema", "stdout_schema", "guest_runtime_schema"] {
+            guard let fileName = io[key] as? String,
+                  GuestContract.Schema(rawValue: fileName) != nil else {
+                throw ScriptExecContractError.integrityFailed(
+                    "script-exec-contract.json io.\(key) must reference a bundled guest schema."
+                )
+            }
+        }
+    }
+
+    private static func validateOutputFields(_ contract: [String: Any]) throws {
+        let envelope = try GuestContract.loadSchemaObject(.envelopeList)
+        guard let properties = (envelope["items"] as? [String: Any])?["properties"] as? [String: Any] else {
+            throw ScriptExecContractError.integrityFailed(
+                "envelope-list.schema.json is missing items.properties."
+            )
+        }
+        let envelopeKeys = Set(properties.keys)
+        guard let output = contract["output"] as? [String: Any],
+              let fields = output["fields"] as? [String: Any] else {
+            return
+        }
+        let missing = Set(fields.keys).subtracting(envelopeKeys)
+        if !missing.isEmpty {
+            throw ScriptExecContractError.integrityFailed(
+                "script-exec-contract.json output.fields references unknown envelope fields: \(missing.sorted().joined(separator: ", "))."
+            )
+        }
+    }
+
+    private static func validateReviewChecks(_ contract: [String: Any]) throws {
+        guard let review = contract["review"] as? [String: Any],
+              let checks = review["checks"] as? [[String: Any]] else {
+            return
+        }
+        var seenIDs: Set<String> = []
+        var seenOrders: Set<Int> = []
+        for check in checks {
+            guard let id = check["id"] as? String,
+                  let order = check["order"] as? Int else {
+                throw ScriptExecContractError.integrityFailed(
+                    "script-exec-contract.json review.checks entries require id and order."
+                )
+            }
+            if seenIDs.contains(id) {
+                throw ScriptExecContractError.integrityFailed(
+                    "script-exec-contract.json review.checks has duplicate id \(id)."
+                )
+            }
+            if seenOrders.contains(order) {
+                throw ScriptExecContractError.integrityFailed(
+                    "script-exec-contract.json review.checks has duplicate order \(order)."
+                )
+            }
+            seenIDs.insert(id)
+            seenOrders.insert(order)
+        }
+    }
+}
diff --git a/packages/Structure/Sources/Contract/ScriptExecContractPrompts.swift b/packages/Structure/Sources/Contract/ScriptExecContractPrompts.swift
new file mode 100644
index 00000000..82278b35
--- /dev/null
+++ b/packages/Structure/Sources/Contract/ScriptExecContractPrompts.swift
@@ -0,0 +1,56 @@
+import Foundation
+
+/// Renders the bundled script_exec protocol for agent, builder, and reviewer prompts.
+public enum ScriptExecContractPrompts: Sendable {
+    public static func builderGuide() -> String {
+        dumpOrUnavailable(preamble: """
+        Offline Go guest rules come only from this protocol JSON and the wire schemas below. \
+        Do not invent requirements that are not in the JSON.
+        """)
+    }
+
+    public static func reviewerGuide() -> String {
+        dumpOrUnavailable(preamble: """
+        You are a reviewer for script_exec declarations. Review against script-exec-contract.json only. \
+        If a rule is not in the JSON, do not require it. Apply review.checks in order; when review.fail_fast \
+        is true, return on the first failing check. Return only valid JSON matching review.response_schema.
+        """)
+    }
+
+    public static func pluginFactoryBuilderGuide() -> String {
+        dumpOrUnavailable(preamble: """
+        Plugin factory builder rules come only from script-exec-contract.json (plugin_factory, runtime, \
+        workflow, output, rules) and connector-contract.json when building a connector. Do not invent \
+        requirements that are not in those JSON documents.
+        """)
+    }
+
+    public static func pluginFactoryReviewerGuide() -> String {
+        dumpOrUnavailable(preamble: """
+        You are Derrick's independent plugin alignment and safety reviewer. Review guest go_source against \
+        script-exec-contract.json (runtime, workflow, output, rules, plugin_factory.review). If a guest rule \
+        is not in the JSON, do not require it. For connector plugins also apply connector-contract.json below. \
+        Return exactly one JSON object matching plugin_factory.review.response_schema.
+        """)
+    }
+
+    public static func dump(preamble: String) throws -> String {
+        _ = try ScriptExecContractStore.loadProtocol()
+        var lines: [String] = [preamble, "", "--- script-exec-contract.json ---"]
+        lines.append(try ScriptExecContractStore.loadProtocolText())
+        lines.append("")
+        lines.append("--- \(GuestContract.Schema.guestRuntime.rawValue) ---")
+        lines.append(try GuestContract.loadSchemaText(.guestRuntime))
+        lines.append("")
+        lines.append("--- \(GuestContract.Schema.hopEvent.rawValue) ---")
+        lines.append(try GuestContract.loadSchemaText(.hopEvent))
+        lines.append("")
+        lines.append("--- \(GuestContract.Schema.envelopeList.rawValue) ---")
+        lines.append(try GuestContract.loadSchemaText(.envelopeList))
+        return lines.joined(separator: "\n")
+    }
+
+    private static func dumpOrUnavailable(preamble: String) -> String {
+        (try? dump(preamble: preamble)) ?? "Script_exec contract JSON failed to load."
+    }
+}
diff --git a/packages/Structure/Sources/Contract/ScriptExecContractStore.swift b/packages/Structure/Sources/Contract/ScriptExecContractStore.swift
new file mode 100644
index 00000000..063fe59f
--- /dev/null
+++ b/packages/Structure/Sources/Contract/ScriptExecContractStore.swift
@@ -0,0 +1,64 @@
+import CryptoKit
+import Foundation
+
+/// Loads the bundled script_exec protocol JSON.
+public enum ScriptExecContractStore: Sendable {
+    public static let protocolResource = "script-exec-contract.json"
+    public static let fingerprintEntries: [(subdirectory: String, file: String)] = [
+        ("schemas", "script-exec-contract.schema.json"),
+        ("schemas", "guest-runtime.schema.json"),
+        ("schemas", "hop-event.schema.json"),
+        ("schemas", "envelope-list.schema.json"),
+        ("contracts", "script-exec-contract.json"),
+    ]
+
+    public static var fingerprintSources: [String] {
+        fingerprintEntries.map { "\($0.subdirectory)/\($0.file)" }
+    }
+
+    public static func loadProtocol() throws -> ScriptExecContractDocument {
+        try ScriptExecContractIntegrity.validateBundledGraph()
+        let data = try resourceData(name: protocolResource, subdirectory: "contracts")
+        do {
+            return try JSONDecoder().decode(ScriptExecContractDocument.self, from: data)
+        } catch {
+            throw ScriptExecContractError.invalidJSON(protocolResource)
+        }
+    }
+
+    public static func loadProtocolText() throws -> String {
+        try utf8Text(resourceData(name: protocolResource, subdirectory: "contracts"))
+    }
+
+    public static func computeFingerprint() throws -> String {
+        var joined = Data()
+        for entry in fingerprintEntries {
+            let relative = "\(entry.subdirectory)/\(entry.file)"
+            let data = try resourceData(name: entry.file, subdirectory: entry.subdirectory)
+            joined.append(Data(relative.utf8))
+            joined.append(0)
+            joined.append(data)
+            joined.append(0)
+        }
+        let digest = SHA256.hash(data: joined)
+        return digest.map { String(format: "%02x", $0) }.joined()
+    }
+
+    static func resourceData(name: String, subdirectory: String) throws -> Data {
+        guard let url = Bundle.module.url(
+            forResource: name,
+            withExtension: nil,
+            subdirectory: subdirectory
+        ) else {
+            throw ScriptExecContractError.missingResource("\(subdirectory)/\(name)")
+        }
+        return try Data(contentsOf: url)
+    }
+
+    private static func utf8Text(_ data: Data) throws -> String {
+        guard let text = String(data: data, encoding: .utf8) else {
+            throw ScriptExecContractError.invalidJSON(protocolResource)
+        }
+        return text
+    }
+}
diff --git a/packages/Structure/Sources/DockerRunnerXPC/DerrickDockerRuntimeIdentity.swift b/packages/Structure/Sources/DockerRunnerXPC/DerrickDockerRuntimeIdentity.swift
index 489d77ac..ca2f57e1 100644
--- a/packages/Structure/Sources/DockerRunnerXPC/DerrickDockerRuntimeIdentity.swift
+++ b/packages/Structure/Sources/DockerRunnerXPC/DerrickDockerRuntimeIdentity.swift
@@ -13,8 +13,8 @@ public enum DerrickDockerRuntimeIdentity: Sendable {
 
     /// Name prefixes for current and unlabeled leftover containers.
     public static let namePrefixes = [
-        "derrick-web-crawler",
-        "derrick-guest-runtime",
+            "derrick-web-crawler",
+            "derrick-guest-runtime",
         "derrick-swift-runtime",
         "derrick-file-extractor",
     ]
diff --git a/packages/Structure/Sources/DockerRunnerXPC/DerrickGoToolchain.swift b/packages/Structure/Sources/DockerRunnerXPC/DerrickGoToolchain.swift
new file mode 100644
index 00000000..7253423f
--- /dev/null
+++ b/packages/Structure/Sources/DockerRunnerXPC/DerrickGoToolchain.swift
@@ -0,0 +1,78 @@
+import Foundation
+
+/// Optional host Go toolchain probe (development diagnostics). Guest compile runs in Docker.
+public enum DerrickGoToolchain: Sendable {
+    public static let minimumVersion = "1.27.1"
+
+    public static func ensureInstalled() throws {
+        let process = Process()
+        process.executableURL = URL(fileURLWithPath: "/usr/bin/env")
+        process.arguments = ["go", "version"]
+        process.environment = [
+            "PATH": "/opt/homebrew/bin:/usr/local/go/bin:/usr/local/bin:/usr/bin:/bin",
+        ]
+        let stdout = Pipe()
+        process.standardOutput = stdout
+        try process.run()
+        process.waitUntilExit()
+        guard process.terminationStatus == 0 else {
+            throw DerrickGoToolchainError.missing
+        }
+        let text = String(data: stdout.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8) ?? ""
+        guard let version = parseVersion(text) else {
+            throw DerrickGoToolchainError.unparseable(text.trimmingCharacters(in: .whitespacesAndNewlines))
+        }
+        guard versionSatisfies(version, minimum: minimumVersion) else {
+            throw DerrickGoToolchainError.tooOld(found: version, required: minimumVersion)
+        }
+    }
+
+    static func parseVersion(_ text: String) -> String? {
+        // go version go1.27.1 darwin/arm64
+        for part in text.split(separator: " ") {
+            let token = String(part)
+            if token.hasPrefix("go"), token.count > 2 {
+                return String(token.dropFirst(2))
+            }
+        }
+        return nil
+    }
+
+    static func versionSatisfies(_ found: String, minimum: String) -> Bool {
+        compareVersions(found, minimum) != .orderedAscending
+    }
+
+    private enum Ordering {
+        case orderedAscending, orderedSame, orderedDescending
+    }
+
+    private static func compareVersions(_ lhs: String, _ rhs: String) -> Ordering {
+        let left = lhs.split(separator: ".").map { Int($0) ?? 0 }
+        let right = rhs.split(separator: ".").map { Int($0) ?? 0 }
+        let count = max(left.count, right.count)
+        for index in 0..<count {
+            let l = index < left.count ? left[index] : 0
+            let r = index < right.count ? right[index] : 0
+            if l < r { return .orderedAscending }
+            if l > r { return .orderedDescending }
+        }
+        return .orderedSame
+    }
+}
+
+public enum DerrickGoToolchainError: Error, LocalizedError, Sendable {
+    case missing
+    case unparseable(String)
+    case tooOld(found: String, required: String)
+
+    public var errorDescription: String? {
+        switch self {
+        case .missing:
+            return "Go \(DerrickGoToolchain.minimumVersion) or later was expected for diagnostics. Guest compile runs in Docker."
+        case .unparseable(let detail):
+            return "Could not read the installed Go version (\(detail))."
+        case .tooOld(let found, let required):
+            return "Go \(required) or later is required to build plugins (found \(found))."
+        }
+    }
+}
diff --git a/packages/Structure/Sources/DockerRunnerXPC/DockerImageDigest.swift b/packages/Structure/Sources/DockerRunnerXPC/DockerImageDigest.swift
new file mode 100644
index 00000000..baa9c04e
--- /dev/null
+++ b/packages/Structure/Sources/DockerRunnerXPC/DockerImageDigest.swift
@@ -0,0 +1,47 @@
+import Foundation
+
+/// SHA-256 image ID from `docker image inspect --format '{{.Id}}'`.
+public struct DockerImageDigest: RawRepresentable, Sendable, Hashable, Codable {
+    public let rawValue: String
+
+    public init(rawValue: String) {
+        self.rawValue = Self.normalize(rawValue)
+    }
+
+    public init?(hexDigest: String) {
+        let normalized = Self.normalize(hexDigest)
+        guard Self.isValid(normalized) else { return nil }
+        rawValue = normalized
+    }
+
+    public static func normalize(_ value: String) -> String {
+        let trimmed = value.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
+        if trimmed.hasPrefix("sha256:") {
+            return trimmed
+        }
+        if trimmed.count == 64 {
+            return "sha256:\(trimmed)"
+        }
+        return trimmed
+    }
+
+    public static func isValid(_ value: String) -> Bool {
+        let hex = value.hasPrefix("sha256:") ? String(value.dropFirst(7)) : value
+        guard hex.count == 64 else { return false }
+        return hex.unicodeScalars.allSatisfy { CharacterSet(charactersIn: "0123456789abcdef").contains($0) }
+    }
+}
+
+public enum DockerImageDigestError: Error, LocalizedError, Sendable, Equatable {
+    case imageMissing(String)
+    case digestMismatch(tag: String, expected: DockerImageDigest, actual: DockerImageDigest)
+
+    public var errorDescription: String? {
+        switch self {
+        case .imageMissing(let tag):
+            return "The worker image \(tag) is not installed."
+        case .digestMismatch(let tag, _, _):
+            return "The worker image \(tag) does not match the version shipped with Derrick. Rebuild or reinstall product images."
+        }
+    }
+}
diff --git a/packages/Structure/Sources/DockerRunnerXPC/DockerProductImageDigests.generated.swift b/packages/Structure/Sources/DockerRunnerXPC/DockerProductImageDigests.generated.swift
new file mode 100644
index 00000000..666ff6bf
--- /dev/null
+++ b/packages/Structure/Sources/DockerRunnerXPC/DockerProductImageDigests.generated.swift
@@ -0,0 +1,6 @@
+import Foundation
+
+/// Generated by scripts/record-docker-image-digests.sh — do not edit.
+public enum DockerProductImageDigests: Sendable {
+    public static let worker = DockerImageDigest(rawValue: "sha256:686c54118b75056b7ca9af17697516fc242e65b7a8da0e43bb6c0a35f31e8052")
+}
diff --git a/packages/Structure/Sources/DockerRunnerXPC/DockerProductImagePolicy.swift b/packages/Structure/Sources/DockerRunnerXPC/DockerProductImagePolicy.swift
index bfbbfd37..9f323fea 100644
--- a/packages/Structure/Sources/DockerRunnerXPC/DockerProductImagePolicy.swift
+++ b/packages/Structure/Sources/DockerRunnerXPC/DockerProductImagePolicy.swift
@@ -1,16 +1,39 @@
 import Foundation
 
-/// Trusted product images built from in-repo Dockerfiles (not pulled from a registry).
+/// Trusted product Docker images built from in-repo Dockerfiles (not pulled from a registry).
 public enum DockerProductImagePolicy: Sendable {
+    public static let workerImage = DockerWorkerRuntime.image
+    public static let workerDockerfileRelativePath = DockerWorkerRuntime.dockerfileRelativePath
+    public static let workerBuildContextRelativePath = DockerWorkerRuntime.buildContextRelativePath
+
+    /// Legacy crawler tag — retained for orphan sweeps only.
     public static let webCrawlerImage = "derrick-web-crawler:swift-6.4-v1"
     public static let webCrawlerDockerfileRelativePath = "docker/web-crawler/Dockerfile"
-    /// Sibling Swift packages only — not the whole git checkout.
     public static let webCrawlerBuildContextRelativePath = "packages"
 
     public static let allowedBuildImageTags: Set<String> = [
-        webCrawlerImage,
+        workerImage,
     ]
 
+    public static func workerBuildContext(repoRoot: URL) -> URL {
+        repoRoot.standardizedFileURL
+    }
+
+    public static func isAllowedWorkerBuild(
+        dockerfilePath: String,
+        imageTag: String,
+        contextPath: String
+    ) -> Bool {
+        guard imageTag == workerImage else { return false }
+        let dockerfileURL = URL(fileURLWithPath: dockerfilePath).standardizedFileURL
+        let contextURL = URL(fileURLWithPath: contextPath).standardizedFileURL
+        let repoRoot = contextURL.standardizedFileURL
+        let expectedDockerfile = repoRoot
+            .appendingPathComponent(workerDockerfileRelativePath)
+            .standardizedFileURL
+        return dockerfileURL.path == expectedDockerfile.path
+    }
+
     public static func webCrawlerBuildContext(repoRoot: URL) -> URL {
         repoRoot.appendingPathComponent(webCrawlerBuildContextRelativePath).standardizedFileURL
     }
diff --git a/packages/Structure/Sources/DockerRunnerXPC/DockerWorkerRuntime.swift b/packages/Structure/Sources/DockerRunnerXPC/DockerWorkerRuntime.swift
new file mode 100644
index 00000000..248376c2
--- /dev/null
+++ b/packages/Structure/Sources/DockerRunnerXPC/DockerWorkerRuntime.swift
@@ -0,0 +1,32 @@
+import Foundation
+
+/// Unified Go worker image shared by crawl, extract, and plugin guest execution.
+public enum DockerWorkerRuntime: Sendable {
+    public static let image = "derrick-worker:go-v1"
+    public static let dockerfileRelativePath = "docker/worker/Dockerfile"
+    public static let buildContextRelativePath = "."
+
+    public static let crawlerBinary = "/usr/local/bin/derrick-web-crawler"
+    public static let extractorBinary = "/usr/local/bin/derrick-file-extractor"
+    /// Binaries that must exist in the unified worker image.
+    public static let requiredBinaries: [String] = [
+        crawlerBinary,
+        extractorBinary,
+    ]
+
+    public static let guestBinaryPath = "/tmp/guest"
+    public static let guestSourcePath = "/tmp/plugin.go"
+    public static let goBinaryPath = "/usr/local/go/bin/go"
+
+    /// Allowed `docker exec … sh -c` payloads for guest source I/O and in-container compile.
+    public static let guestWriteSourceShell = "cat > /tmp/plugin.go"
+    public static let guestCompileShell =
+        "cd /tmp && /usr/local/go/bin/go build -trimpath -ldflags=\"-s -w\" -o guest plugin.go && chmod +x guest"
+    public static let guestReadBinaryShell = "cat /tmp/guest"
+
+    public static let pinnedDigest = DockerProductImageDigests.worker
+
+    /// OCI label written by `docker/worker/Dockerfile`; used to detect stale local images.
+    public static let binariesLabelKey = "derrick.worker.binaries"
+    public static let binariesLabelValue = "crawler,extractor"
+}
diff --git a/packages/Structure/Sources/MCPServer/MCPServerContractTypes.swift b/packages/Structure/Sources/MCPServer/MCPServerContractTypes.swift
index 5fb77b5d..80d556d8 100644
--- a/packages/Structure/Sources/MCPServer/MCPServerContractTypes.swift
+++ b/packages/Structure/Sources/MCPServer/MCPServerContractTypes.swift
@@ -2,11 +2,11 @@ import Foundation
 import MCP
 
 public enum GuestScriptLanguage: String, Sendable, Equatable {
-    case python
+    case go
 
-    public var verifierID: String { "python-check-v1" }
+    public var verifierID: String { "go-check-v1" }
 
-    /// `language` is optional and must be Python when set.
+    /// `language` is optional and must be Go when set.
     public static func requestedLanguageIsUnsupported(_ arguments: [String: Value]) -> Bool {
         guard let raw = arguments["language"]?.stringValue?
             .trimmingCharacters(in: .whitespacesAndNewlines)
@@ -15,7 +15,7 @@ public enum GuestScriptLanguage: String, Sendable, Equatable {
         else {
             return false
         }
-        return raw != "python" && raw != "py"
+        return raw != "go" && raw != "golang"
     }
 }
 
diff --git a/packages/Structure/Sources/MCPServer/ScriptExecutionModels.swift b/packages/Structure/Sources/MCPServer/ScriptExecutionModels.swift
index 97481bae..3e59478a 100644
--- a/packages/Structure/Sources/MCPServer/ScriptExecutionModels.swift
+++ b/packages/Structure/Sources/MCPServer/ScriptExecutionModels.swift
@@ -59,7 +59,7 @@ public enum ScriptFailureStage: String, Codable, Sendable, Equatable {
     case none
     /// Static verifier rejected the request before run.
     case staticValidation
-    /// Leftover Swift compiler stage. Guest scripts are Python; this case remains for stored outcomes.
+    /// Go compile stage before container execution.
     case typecheck
     /// LLM security reviewer rejected (or could not complete when required).
     case llmReview
@@ -253,7 +253,7 @@ public struct ScriptExecutionResult: Sendable {
         stderr: String,
         durationMS: Int,
         phaseTiming: ScriptPhaseTiming?,
-        verifier: String = "python-check-v1"
+        verifier: String = "go-check-v1"
     ) -> ScriptExecutionResult {
         let combined = stdout + "\n" + stderr
         let looksLikeEgress = combined.localizedCaseInsensitiveContains("UNAUTHORIZED_EGRESS")
diff --git a/packages/Structure/Sources/MCPToolCatalog/AllowedMCPTool.swift b/packages/Structure/Sources/MCPToolCatalog/AllowedMCPTool.swift
index 2976abe7..a2ff70bd 100644
--- a/packages/Structure/Sources/MCPToolCatalog/AllowedMCPTool.swift
+++ b/packages/Structure/Sources/MCPToolCatalog/AllowedMCPTool.swift
@@ -43,7 +43,7 @@ public enum AllowedMCPTool: String, CaseIterable, Sendable, Codable, Hashable {
     public var defaultDescription: String {
         switch self {
         case .scriptExec:
-            return "Run declared standalone Python in a constrained Docker container after verification. Emit HTTP request envelopes; the host performs the request."
+            return "Run declared standalone Go in a constrained Docker container after verification. Emit HTTP request envelopes; the host performs the request."
         case .sessionMemorySearch:
             return "Search prior session memory entries with optional query and paging."
         case .agentsSpawn:
@@ -69,7 +69,7 @@ public enum AllowedMCPTool: String, CaseIterable, Sendable, Codable, Hashable {
         case .pluginInvoke:
             return "Run one approved compiled Agent Plugin by id with a JSON input object."
         case .webCrawl:
-            return "Crawl a bounded same-origin website in an isolated Swift container and return structured page summaries."
+            return "Crawl a bounded same-origin website in an isolated container and return structured page summaries. Call directly in chat; use jobs_create only for crawls likely to exceed about one minute."
         case .filesExtract:
             return "Extract text or convert attached chat files (PDF, DOCX, XLSX, CSV, HTML) in an isolated Swift container. Call this tool directly; do not submit it through jobs_create."
         }
diff --git a/packages/Structure/Sources/Plugin/Envelope/DerrickGuestGo.swift b/packages/Structure/Sources/Plugin/Envelope/DerrickGuestGo.swift
new file mode 100644
index 00000000..033bd9e7
--- /dev/null
+++ b/packages/Structure/Sources/Plugin/Envelope/DerrickGuestGo.swift
@@ -0,0 +1,50 @@
+import Foundation
+
+/// Go contract shown to models that generate Derrick plugin guest programs.
+public enum DerrickGuestGo: Sendable {
+    public static func source(for spec: PluginSpec? = nil) throws -> String {
+        var sections = [ScriptExecContractPrompts.builderGuide()]
+        if let spec {
+            sections.append(
+                """
+                Plugin parameters are delivered in the input object's `params` object.
+                The parameter contract is:
+                \(try spec.goParameterDeclaration())
+
+                --- \(GuestContract.Schema.connectorParams.rawValue) ---
+                \(try GuestContract.loadSchemaText(.connectorParams))
+                """
+            )
+        }
+        return sections.joined(separator: "\n\n")
+    }
+}
+
+private extension PluginSpec {
+    func goParameterDeclaration() throws -> String {
+        _ = try validated()
+        let fields = parameters.map { parameter in
+            "    \(parameter.name) \(parameterType(parameter.type))"
+        }
+        return """
+        type PluginParams struct {
+        \(fields.joined(separator: "\n"))
+        }
+        """
+    }
+
+    func parameterType(_ type: PluginParameterType) -> String {
+        switch type {
+        case .string:
+            return "string"
+        case .number:
+            return "float64"
+        case .boolean:
+            return "bool"
+        case .stringList:
+            return "[]string"
+        case .numberList:
+            return "[]float64"
+        }
+    }
+}
diff --git a/packages/Structure/Sources/Plugin/Envelope/DerrickGuestPython.swift b/packages/Structure/Sources/Plugin/Envelope/DerrickGuestPython.swift
deleted file mode 100644
index 3ef8d5e7..00000000
--- a/packages/Structure/Sources/Plugin/Envelope/DerrickGuestPython.swift
+++ /dev/null
@@ -1,81 +0,0 @@
-import Foundation
-
-/// Python contract shown to models that generate standalone Derrick guest programs.
-public enum DerrickGuestPython: Sendable {
-    public static let modelContract = """
-    Python guest contract:
-    - The program is a standalone Python script run as `python3 /tmp/guest.py`.
-    - Read one JSON object from standard input (`sys.stdin`).
-    - Write one JSON array of envelope objects to standard output. Every object needs `verb` from the envelope-list schema.
-    - POST bodies go in `json`. The host decodes `http.request` as HostHTTPRequest and sends `json` as the HTTP body.
-    - On the first event, emit `http.request` envelopes for host HTTP.
-    - On an `http_results` event, emit `result.emit` or `message.post`.
-    - The host, not the Python container, performs HTTP and supplies response bodies.
-    - Do not use socket, urllib, requests, httpx, subprocess, or filesystem access.
-    - Use only the Python standard library (no pip/uv dependencies in script_exec).
-    - For repeatable output, match HTTP responses by request_id, sort and de-duplicate collections
-      by stable keys, and never use current time, randomness, UUIDs, response arrival order, or
-      dict/set iteration order for user-visible output.
-    - Later http_results events include earlier responses plus the newest ones. Match by request_id.
-
-    Minimal output pattern:
-    ```python
-    import json, sys
-    event = json.load(sys.stdin)
-    def emit(envelopes):
-        json.dump(envelopes, sys.stdout, separators=(",", ":"))
-    ```
-    Inspect `event.get("kind")` and `event.get("http_results")` to choose the next envelopes.
-
-    Example request envelope:
-    {"verb":"http.request","request_id":"news-1","method":"GET","url":"https://example.com/feed.xml"}
-
-    POST bodies: put the JSON value in `json`. The host deserializes `http.request` into HostHTTPRequest and sends `json` as the HTTP body.
-    {"verb":"http.request","request_id":"send-1","method":"POST","url":"https://example.com/api","headers":{"Content-Type":"application/json"},"json":{"channel":"C1","text":"hello"}}
-
-    Example result envelope:
-    {"verb":"result.emit","title":"Result","summary":"User-readable output"}
-    """
-
-    public static func source(for spec: PluginSpec? = nil) throws -> String {
-        var sections = [modelContract]
-        if let spec {
-            sections.append(
-                """
-                Plugin parameters are delivered in the input object's `params` object.
-                The parameter contract is:
-                \(try spec.pythonParameterDeclaration())
-                """
-            )
-        }
-        return sections.joined(separator: "\n\n")
-    }
-}
-
-private extension PluginSpec {
-    func pythonParameterDeclaration() throws -> String {
-        _ = try validated()
-        let fields = parameters.map { parameter in
-            "    \(parameter.name): \(parameterType(parameter.type))"
-        }
-        return """
-        class PluginParams(TypedDict):
-        \(fields.joined(separator: "\n"))
-        """
-    }
-
-    func parameterType(_ type: PluginParameterType) -> String {
-        switch type {
-        case .string:
-            return "str"
-        case .number:
-            return "float"
-        case .boolean:
-            return "bool"
-        case .stringList:
-            return "list[str]"
-        case .numberList:
-            return "list[float]"
-        }
-    }
-}
diff --git a/packages/Structure/Sources/Plugin/Factory/PluginFactoryRuntimeTypes.swift b/packages/Structure/Sources/Plugin/Factory/PluginFactoryRuntimeTypes.swift
index 5548c6a3..20586073 100644
--- a/packages/Structure/Sources/Plugin/Factory/PluginFactoryRuntimeTypes.swift
+++ b/packages/Structure/Sources/Plugin/Factory/PluginFactoryRuntimeTypes.swift
@@ -1,7 +1,7 @@
 import Foundation
 
 public enum PluginGuestLanguage: String, Sendable, Equatable, Codable {
-    case python
+    case go
 }
 
 /// Parsed `app.derrick/runtime.json` from an approved factory release.
@@ -9,7 +9,7 @@ public struct PluginFactoryRuntime: Sendable, Equatable {
     public let language: PluginGuestLanguage
     public let entrypoint: String
 
-    public init(language: PluginGuestLanguage = .python, entrypoint: String) {
+    public init(language: PluginGuestLanguage = .go, entrypoint: String) {
         self.language = language
         self.entrypoint = entrypoint
     }
@@ -22,6 +22,36 @@ public struct PluginFactoryRuntime: Sendable, Equatable {
         else {
             return nil
         }
-        return PluginFactoryRuntime(entrypoint: entrypoint)
+        let languageRaw = (object["language"] as? String) ?? PluginGuestLanguage.go.rawValue
+        let language = PluginGuestLanguage(rawValue: languageRaw) ?? .go
+        return PluginFactoryRuntime(language: language, entrypoint: entrypoint)
+    }
+
+    /// Package-relative guest source path used when hashing and verifying releases.
+    public static func guestSourcePackagePath(
+        runtimeJSON: String,
+        manifestJSON: String,
+        defaultPath: String = "app.derrick/plugin.go"
+    ) -> String {
+        if let runtime = decode(from: runtimeJSON) {
+            return normalizePackageRelativePath(runtime.entrypoint)
+        }
+        if let data = manifestJSON.data(using: .utf8),
+           let manifest = try? AgentPluginManifest.decode(data),
+           let entrypoint = manifest.derrick?.entrypoint {
+            return normalizePackageRelativePath(entrypoint)
+        }
+        return defaultPath
+    }
+
+    private static func normalizePackageRelativePath(_ entrypoint: String) -> String {
+        var path = entrypoint.trimmingCharacters(in: .whitespacesAndNewlines)
+        if path.hasPrefix("./") {
+            path = String(path.dropFirst(2))
+        }
+        while path.hasPrefix("/") {
+            path = String(path.dropFirst())
+        }
+        return path
     }
 }
diff --git a/packages/Structure/Sources/Plugin/Factory/PluginFactoryTestScript.swift b/packages/Structure/Sources/Plugin/Factory/PluginFactoryTestScript.swift
index aaed1995..74169873 100644
--- a/packages/Structure/Sources/Plugin/Factory/PluginFactoryTestScript.swift
+++ b/packages/Structure/Sources/Plugin/Factory/PluginFactoryTestScript.swift
@@ -77,7 +77,10 @@ public enum PluginFactoryHopTestRunner: Sendable {
         testInput: Data,
         executor: any PluginFactoryExecutor
     ) async throws -> PluginFactoryHopTestRun {
-        try await run(testInput: testInput) { input in
+        if let compiled = executor as? any PluginFactoryCompiledGuestExecutor {
+            return try await compiled.runGuestSourceHops(source: source, testInput: testInput)
+        }
+        return try await run(testInput: testInput) { input in
             try await executor.runGuestSource(source: source, input: input)
         }
     }
diff --git a/packages/Structure/Sources/Plugin/Factory/PluginFactoryTypes.swift b/packages/Structure/Sources/Plugin/Factory/PluginFactoryTypes.swift
index bea96cf2..fdecbf55 100644
--- a/packages/Structure/Sources/Plugin/Factory/PluginFactoryTypes.swift
+++ b/packages/Structure/Sources/Plugin/Factory/PluginFactoryTypes.swift
@@ -2,9 +2,9 @@ import Foundation
 
 public typealias PluginFactoryLogger = @Sendable (String) async -> Void
 
-/// The factory creates Agent Plugin packages whose Derrick entrypoint is Python.
-/// A draft is a standalone file: the container runs it with `python3 /tmp/guest.py`.
-/// A released version stores UTF-8 source as the packaged artifact.
+/// The factory creates Agent Plugin packages whose Derrick entrypoint is Go.
+/// A draft is compiled to a Linux binary and run as `/tmp/guest` in the worker image.
+/// A released version stores the compiled binary as the packaged artifact.
 public struct PluginFactoryDraft: Sendable, Hashable {
     public let manifestJSON: String
     public let guestSource: String
@@ -146,7 +146,7 @@ public struct PluginFactoryManifestInput: Sendable, Hashable {
             throw PluginFactoryError.invalidManifest("Version is required.")
         }
         var derrick: [String: Any] = [
-            "entrypoint": "./app.derrick/plugin.py",
+            "entrypoint": "./app.derrick/plugin.go",
         ]
         if !secrets.isEmpty {
             derrick["secrets"] = secrets.map(\.jsonObject)
@@ -204,7 +204,7 @@ public struct PluginFactoryBuilderRequest: Sendable, Hashable {
     public let userGoal: String
     public let previousDraft: PluginFactoryDraft?
     public let feedback: String?
-    /// When set, the host writes `plugin.json`. The builder only supplies Python and tests.
+    /// When set, the host writes `plugin.json`. The builder only supplies Go source and tests.
     public let hostManifest: PluginFactoryManifestInput?
 
     public init(
@@ -288,7 +288,7 @@ public struct PluginFactoryBuilderResponse: Codable, Sendable, Hashable {
     enum CodingKeys: String, CodingKey {
         case pluginID = "plugin_id"
         case version, description
-        case guestSource = "python_source"
+        case guestSource = "go_source"
         case legacySwiftSource = "swift_source"
         case testInputJSON = "test_input_json"
         case skillFiles = "skill_files"
@@ -380,14 +380,19 @@ public struct PluginFactoryExecutionResult: Sendable, Hashable {
     }
 }
 
-/// The host supplies this adapter. Its production implementation runs these
-/// commands inside the restricted Linux Swift Docker container.
+/// The host supplies this adapter. Its production implementation compiles and
+/// runs guests inside the pinned Go worker Docker container.
 public protocol PluginFactoryExecutor: Sendable {
     func runGuestSource(source: String, input: Data) async throws -> PluginFactoryExecutionResult
     func packageGuestSource(source: String) async throws -> Data
     func runPackagedArtifact(_ artifact: Data, input: Data) async throws -> PluginFactoryExecutionResult
 }
 
+/// Optional compile-once hop replay for factory direct tests.
+public protocol PluginFactoryCompiledGuestExecutor: PluginFactoryExecutor {
+    func runGuestSourceHops(source: String, testInput: Data) async throws -> PluginFactoryHopTestRun
+}
+
 public enum PluginReviewDecision: String, Sendable, Hashable {
     case approved
     case rejected
@@ -526,10 +531,14 @@ public struct PluginFactoryRelease: Sendable, Hashable {
     }
 
     public func packageFiles() -> [String: Data] {
+        let guestPath = PluginFactoryRuntime.guestSourcePackagePath(
+            runtimeJSON: runtimeJSON,
+            manifestJSON: manifestJSON
+        )
         var files: [String: Data] = [
             "plugin.json": Data(manifestJSON.utf8),
             "app.derrick/runtime.json": Data(runtimeJSON.utf8),
-            "app.derrick/plugin.py": Data(guestSource.utf8),
+            guestPath: Data(guestSource.utf8),
             "app.derrick/plugin": compiledArtifact,
         ]
         for (path, body) in skillFiles {
@@ -571,15 +580,15 @@ public enum PluginFactoryError: Error, LocalizedError, Equatable, Sendable {
         case .invalidSkillPath(let path):
             return "Invalid skill path '\(path)'. Skill path must be skills/<name>/SKILL.md."
         case .reservedPluginID(let id): return "The plugin id '\(id)' is reserved by Derrick."
-        case .invalidSource(let message): return "Invalid Python guest source: \(message)"
-        case .directRunFailed(let message): return "Python draft test failed: \(message)"
-        case .invalidDirectOutput(let message): return "Python draft returned invalid plugin output: \(message)"
+        case .invalidSource(let message): return "Invalid Go guest source: \(message)"
+        case .directRunFailed(let message): return "Go draft test failed: \(message)"
+        case .invalidDirectOutput(let message): return "Go draft returned invalid plugin output: \(message)"
         case .reviewRejected(let summary, let findings):
             let detail = findings.isEmpty
                 ? summary
                 : "\(summary) \(findings.joined(separator: " "))"
             return "Plugin review rejected the draft: \(detail)"
-        case .packageFailed(let message): return "Python plugin packaging failed: \(message)"
+        case .packageFailed(let message): return "Go plugin packaging failed: \(message)"
         case .packagedRunFailed(let message): return "Packaged plugin test failed: \(message)"
         case .invalidPackagedOutput(let message): return "Packaged plugin returned invalid output: \(message)"
         case .draftValidationFailed(let findings):
diff --git a/packages/Structure/Sources/Plugin/Manifest/DerrickRuntime.swift b/packages/Structure/Sources/Plugin/Manifest/DerrickRuntime.swift
index bcfe23ef..9b95c902 100644
--- a/packages/Structure/Sources/Plugin/Manifest/DerrickRuntime.swift
+++ b/packages/Structure/Sources/Plugin/Manifest/DerrickRuntime.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-/// Derrick runtime metadata (`app.derrick/runtime.json`) for a standalone Python entrypoint.
+/// Derrick runtime metadata (`app.derrick/runtime.json`) for a standalone Go entrypoint.
 public struct DerrickRuntime: Codable, Sendable, Hashable {
     public var entrypoint: String
     public var dependencies: [String: String]
@@ -66,7 +66,7 @@ public struct DerrickRuntime: Codable, Sendable, Hashable {
         if trimmed.hasPrefix("./") {
             return try PluginPath.validateRuntimeEntrypoint(trimmed)
         }
-        guard trimmed.hasSuffix(".py"),
+        guard trimmed.hasSuffix(".go"),
               !trimmed.contains("/"),
               !trimmed.contains("\\") else {
             throw PluginManifestError.invalidEntrypoint(raw)
diff --git a/packages/Structure/Sources/Plugin/Manifest/PluginManifestError.swift b/packages/Structure/Sources/Plugin/Manifest/PluginManifestError.swift
index 8a08c898..d575c57b 100644
--- a/packages/Structure/Sources/Plugin/Manifest/PluginManifestError.swift
+++ b/packages/Structure/Sources/Plugin/Manifest/PluginManifestError.swift
@@ -47,7 +47,7 @@ public enum PluginManifestError: Error, Equatable, LocalizedError {
         case .invalidFieldType(let f):
             return "plugin.json field has the wrong type: \(f)"
         case .invalidEntrypoint(let p):
-            return "Entrypoint must be a plugin-relative .py path: \(p)"
+            return "Entrypoint must be a plugin-relative .go path: \(p)"
         case .pathNotRelative(let p):
             return "Path must be plugin-relative and start with ./: \(p)"
         case .pathEscapesRoot(let p):
diff --git a/packages/Structure/Sources/Plugin/Manifest/PluginPath.swift b/packages/Structure/Sources/Plugin/Manifest/PluginPath.swift
index f5cf9141..fd5df8c3 100644
--- a/packages/Structure/Sources/Plugin/Manifest/PluginPath.swift
+++ b/packages/Structure/Sources/Plugin/Manifest/PluginPath.swift
@@ -19,18 +19,18 @@ public enum PluginPath {
         return trimmed
     }
 
-    /// Python factory entrypoints are standalone files run by `python3`.
-    public static func validatePythonEntrypoint(_ raw: String) throws -> String {
+    /// Go factory entrypoints are standalone `package main` files compiled to `/tmp/guest`.
+    public static func validateGoEntrypoint(_ raw: String) throws -> String {
         let path = try validateRelative(raw)
-        guard path.hasSuffix(".py") else {
+        guard path.hasSuffix(".go") else {
             throw PluginManifestError.invalidEntrypoint(raw)
         }
         return path
     }
 
-    /// Accepts the supported Derrick guest runtime source file (.py).
+    /// Accepts the supported Derrick guest runtime source file (.go).
     public static func validateRuntimeEntrypoint(_ raw: String) throws -> String {
-        try validatePythonEntrypoint(raw)
+        try validateGoEntrypoint(raw)
     }
 
     public static func resolve(root: URL, relative: String) throws -> URL {
diff --git a/packages/Structure/Tests/StructureTests/AppLayerServicesWireTests.swift b/packages/Structure/Tests/StructureTests/AppLayerServicesWireTests.swift
index 5d8b2588..40413446 100644
--- a/packages/Structure/Tests/StructureTests/AppLayerServicesWireTests.swift
+++ b/packages/Structure/Tests/StructureTests/AppLayerServicesWireTests.swift
@@ -84,11 +84,11 @@ import Testing
         #expect(decoded.executableFingerprint == nil)
     }
 
-    @Test func bundledScriptReviewerInstructionsLoadFromSourceTree() throws {
-        let scriptReviewer = try DerrickBundledText.load("script_reviewer_instructions.md")
-        #expect(scriptReviewer.contains("intent alignment"))
-        #expect(scriptReviewer.contains("secret literals"))
-        #expect(scriptReviewer.contains("Python verifier"))
+    @Test func scriptExecReviewerPromptLoadsFromBundledContract() {
+        let scriptReviewer = ScriptExecContractPrompts.reviewerGuide()
+        #expect(scriptReviewer.contains("script-exec-contract.json"))
+        #expect(scriptReviewer.contains("intent_alignment"))
+        #expect(scriptReviewer.contains("If a rule is not in the JSON"))
     }
 
     @Test func healthDecodesLegacyPayloadWithoutGuestRuntime() throws {
@@ -369,7 +369,7 @@ import Testing
     @Test func slackConnectorFallsBackToBotTokenWhenManifestOmitsSecrets() {
         let json = """
         {"$schema":"https://example.invalid/agent-plugin.json","name":"slack-connector","version":"1.0.0",\
-        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","messaging_ops":["sync_threads"]}}}
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","messaging_ops":["sync_threads"]}}}
         """
         let descriptors = PluginSecretField.resolvedDescriptors(
             pluginID: "slack-connector",
@@ -1022,15 +1022,15 @@ import Testing
                 reportedFingerprint: "a",
                 expectedFingerprint: "a",
                 reportedGuestRuntime: DerrickGuestRuntime.swiftPluginDockerImage,
-                expectedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage
+                expectedGuestRuntime: DerrickGuestRuntime.guestDockerImage
             )
         )
         #expect(
             !DerrickDaemonHygiene.shouldRetireConnectedDaemon(
                 reportedFingerprint: "a",
                 expectedFingerprint: "a",
-                reportedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage,
-                expectedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage
+                reportedGuestRuntime: DerrickGuestRuntime.guestDockerImage,
+                expectedGuestRuntime: DerrickGuestRuntime.guestDockerImage
             )
         )
         #expect(
@@ -1038,7 +1038,7 @@ import Testing
                 reportedFingerprint: "old",
                 expectedFingerprint: "new",
                 reportedGuestRuntime: DerrickGuestRuntime.swiftPluginDockerImage,
-                expectedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage
+                expectedGuestRuntime: DerrickGuestRuntime.guestDockerImage
             )
         )
         #expect(
@@ -1046,7 +1046,7 @@ import Testing
                 reportedFingerprint: "a",
                 expectedFingerprint: "a",
                 reportedGuestRuntime: "stale-guest:old",
-                expectedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage
+                expectedGuestRuntime: DerrickGuestRuntime.guestDockerImage
             )
         )
         #expect(
@@ -1054,7 +1054,7 @@ import Testing
                 reportedFingerprint: nil,
                 expectedFingerprint: "a",
                 reportedGuestRuntime: DerrickGuestRuntime.swiftPluginDockerImage,
-                expectedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage
+                expectedGuestRuntime: DerrickGuestRuntime.guestDockerImage
             )
         )
         #expect(
@@ -1062,7 +1062,7 @@ import Testing
                 reportedFingerprint: "a",
                 expectedFingerprint: nil,
                 reportedGuestRuntime: DerrickGuestRuntime.swiftPluginDockerImage,
-                expectedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage
+                expectedGuestRuntime: DerrickGuestRuntime.guestDockerImage
             )
         )
     }
@@ -1214,10 +1214,10 @@ import Testing
         #expect(!DerrickDockerRuntimeIdentity.isAllowedPsFilter("name=nginx"))
         #expect(
             DerrickDockerRuntimeIdentity.createHasRuntimeLabel(
-                ["create"] + DerrickDockerRuntimeIdentity.createLabelArguments + ["python:3.14.7"]
+                ["create"] + DerrickDockerRuntimeIdentity.createLabelArguments + [DockerWorkerRuntime.image]
             )
         )
-        #expect(!DerrickDockerRuntimeIdentity.createHasRuntimeLabel(["create", "--name", "x", "python:3.14.7"]))
+        #expect(!DerrickDockerRuntimeIdentity.createHasRuntimeLabel(["create", "--name", "x", DockerWorkerRuntime.image]))
     }
 
     @Test func webCrawlerProductImageBuildUsesPackagesContext() {
@@ -1317,12 +1317,12 @@ import Testing
         )
     }
 
-    @Test func effectorAdmissionDeniesLiveChatWithoutContext() {
+    @Test func effectorAdmissionAllowsLiveChatWithoutContext() {
         #expect(
             EffectorAdmissionPolicy.allowsSyncWebCrawl(
                 context: nil,
                 principal: .agent(sessionID: "s1", agentID: "a1")
-            ) == false
+            )
         )
     }
 
@@ -1476,17 +1476,16 @@ import Testing
         #expect(!PluginFactoryValidationExpectations.isSendOnlyConnector(manifestJSON: sendAndReceive))
     }
 
-    @Test func connectorFactoryFailureReturnsToVendorStep() {
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "docs") == .vendor)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "factory") == .vendor)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "review") == .vendor)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "description") == .vendor)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "type") == .type)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "name") == .name)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "auth") == .auth)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "discover") == .auth)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "paywall") == .news)
-        #expect(PluginFactoryCreateInput.failureStep(forStage: "news") == .news)
+    @Test func pluginStudioFailureMapsToSkillFirstSteps() {
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "docs") == .build)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "factory") == .build)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "review") == .build)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "description") == .skill)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "type") == .skill)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "name") == .skill)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "auth") == .credentials)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "discover") == .credentials)
+        #expect(PluginFactoryCreateInput.failureStep(forStage: "goal") == .goal)
     }
 
     @Test func connectorWizardOffersFullSyncOnly() {
diff --git a/packages/Structure/Tests/StructureTests/ConnectorContractTests.swift b/packages/Structure/Tests/StructureTests/ConnectorContractTests.swift
index 8bde0814..6ab15dec 100644
--- a/packages/Structure/Tests/StructureTests/ConnectorContractTests.swift
+++ b/packages/Structure/Tests/StructureTests/ConnectorContractTests.swift
@@ -204,7 +204,7 @@ private func slackFullSyncGoal() -> String {
 private func slackFullSyncManifestJSON() -> String {
     """
     {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-connection","version":"1.0.0",\
-    "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
+    "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
     """
 }
 
diff --git a/packages/Structure/Tests/StructureTests/DerrickGoToolchainTests.swift b/packages/Structure/Tests/StructureTests/DerrickGoToolchainTests.swift
new file mode 100644
index 00000000..b618f0f7
--- /dev/null
+++ b/packages/Structure/Tests/StructureTests/DerrickGoToolchainTests.swift
@@ -0,0 +1,29 @@
+import Testing
+@testable import Structure
+
+@Suite struct DerrickGoToolchainTests {
+    @Test func minimumVersionIsPinned() {
+        #expect(DerrickGoToolchain.minimumVersion == "1.27.1")
+    }
+
+    @Test func parseVersionReadsGoVersionLine() {
+        #expect(
+            DerrickGoToolchain.parseVersion("go version go1.27.1 darwin/arm64") == "1.27.1"
+        )
+    }
+
+    @Test func parseVersionRejectsEmptyOutput() {
+        #expect(DerrickGoToolchain.parseVersion("") == nil)
+        #expect(DerrickGoToolchain.parseVersion("go version") == nil)
+    }
+
+    @Test func versionSatisfiesAcceptsCurrentAndNewer() {
+        #expect(DerrickGoToolchain.versionSatisfies("1.27.1", minimum: "1.27.1"))
+        #expect(DerrickGoToolchain.versionSatisfies("1.28.0", minimum: "1.27.1"))
+    }
+
+    @Test func versionSatisfiesRejectsOlder() {
+        #expect(!DerrickGoToolchain.versionSatisfies("1.27.0", minimum: "1.27.1"))
+        #expect(!DerrickGoToolchain.versionSatisfies("1.26.9", minimum: "1.27.1"))
+    }
+}
diff --git a/packages/Structure/Tests/StructureTests/GuestContractTests.swift b/packages/Structure/Tests/StructureTests/GuestContractTests.swift
index d8c3d834..58d1a06d 100644
--- a/packages/Structure/Tests/StructureTests/GuestContractTests.swift
+++ b/packages/Structure/Tests/StructureTests/GuestContractTests.swift
@@ -10,6 +10,12 @@ import Testing
         }
     }
 
+    @Test func guestRuntimeSchemaRequiresGoLanguage() throws {
+        let schema = try GuestContract.loadSchemaObject(.guestRuntime)
+        let language = (schema["properties"] as? [String: Any])?["language"] as? [String: Any]
+        #expect(language?["const"] as? String == "go")
+    }
+
     @Test func executionContextSchemaExposesWorkflowKinds() throws {
         let kinds = try GuestContract.officialWorkflowKinds()
         #expect(kinds.contains("plugin_factory_create"))
@@ -104,4 +110,37 @@ import Testing
             try GuestContract.validate(json: Data(json.utf8), against: .envelopeList)
         }
     }
+
+    @Test func webCrawlerResultValidationAcceptsMinimalSuccess() throws {
+        let json = """
+        {"ok":true,"start_url":"https://example.com/","pages":[],"stop_reason":"completed","requests_made":0,"bytes_read":0,"truncated":false,"diagnostics":[]}
+        """
+        try GuestContractValidation.validateWebCrawlerResultJSON(Data(json.utf8))
+    }
+
+    @Test func webCrawlerResultValidationRejectsNullDiagnostics() {
+        let json = """
+        {"ok":true,"start_url":"https://example.com/","pages":[],"stop_reason":"completed","requests_made":0,"bytes_read":0,"truncated":false,"diagnostics":null}
+        """
+        #expect(throws: GuestContractError.self) {
+            try GuestContractValidation.validateWebCrawlerResultJSON(Data(json.utf8))
+        }
+    }
+
+    @Test func fileExtractorResultValidationAcceptsMinimalSuccess() throws {
+        let json = """
+        {"ok":true,"operation":"extract","files":[],"diagnostics":[]}
+        """
+        try GuestContractValidation.validateFileExtractorResultJSON(Data(json.utf8))
+    }
+
+    @Test func fileExtractorResultValidationRejectsNullFiles() {
+        let json = """
+        {"ok":false,"operation":"extract","files":null,"diagnostics":[]}
+        """
+        #expect(throws: GuestContractError.self) {
+            try GuestContractValidation.validateFileExtractorResultJSON(Data(json.utf8))
+        }
+    }
+
 }
diff --git a/packages/Structure/Tests/StructureTests/NewsPaywallTests.swift b/packages/Structure/Tests/StructureTests/NewsPaywallTests.swift
new file mode 100644
index 00000000..0659531a
--- /dev/null
+++ b/packages/Structure/Tests/StructureTests/NewsPaywallTests.swift
@@ -0,0 +1,29 @@
+import Foundation
+import Testing
+import Structure
+
+@Suite struct NewsPaywallTests {
+    @Test func paywallWarningIsUserFacing() {
+        #expect(NewsPaywall.userWarning.localizedCaseInsensitiveContains("paywall"))
+        #expect(NewsPaywall.userWarning.localizedCaseInsensitiveContains("not supported"))
+    }
+
+    @Test func preflightRejectsPaywalledArticleAllowsFeed() {
+        #expect(
+            NewsPaywall.preflightRejection(
+                url: URL(string: "https://www.nytimes.com/2024/01/01/world.html")!
+            ) != nil
+        )
+        #expect(
+            NewsPaywall.preflightRejection(
+                url: URL(string: "https://rss.nytimes.com/services/xml/rss/nyt/HomePage.xml")!
+            ) == nil
+        )
+    }
+
+    @Test func canonicalFetchURLUpgradesGeneralGoogleNewsRSSForTechHint() {
+        let url = URL(string: "https://news.google.com/rss?hl=en-US&gl=US&ceid=US:en")!
+        let canonical = NewsSourceURL.canonicalFetchURL(url, contextHint: "tech-news Tech")
+        #expect(canonical.path.contains("/headlines/section/topic/TECHNOLOGY"))
+    }
+}
diff --git a/packages/Structure/Tests/StructureTests/NewsReaderTests.swift b/packages/Structure/Tests/StructureTests/NewsReaderTests.swift
deleted file mode 100644
index 7b0f12a5..00000000
--- a/packages/Structure/Tests/StructureTests/NewsReaderTests.swift
+++ /dev/null
@@ -1,178 +0,0 @@
-import Foundation
-import Testing
-import Structure
-
-@Suite struct NewsReaderTests {
-    @Test func paywallWarningIsUserFacing() {
-        #expect(NewsPaywall.userWarning.localizedCaseInsensitiveContains("paywall"))
-        #expect(NewsPaywall.userWarning.localizedCaseInsensitiveContains("not supported"))
-    }
-
-    @Test func preflightRejectsPaywalledArticleAllowsFeed() {
-        #expect(
-            NewsPaywall.preflightRejection(
-                url: URL(string: "https://www.nytimes.com/2024/01/01/world.html")!
-            ) != nil
-        )
-        #expect(
-            NewsPaywall.preflightRejection(
-                url: URL(string: "https://rss.nytimes.com/services/xml/rss/nyt/HomePage.xml")!
-            ) == nil
-        )
-        #expect(
-            NewsPaywall.preflightRejection(
-                url: URL(string: "https://feeds.bbci.co.uk/news/rss.xml")!
-            ) == nil
-        )
-    }
-
-    @Test func knownPaywallHostIsDetected() {
-        #expect(NewsPaywall.hostLooksPaywalled(URL(string: "https://www.nytimes.com/2024/01/01/world.html")!))
-        #expect(!NewsPaywall.hostLooksPaywalled(URL(string: "https://feeds.bbci.co.uk/news/rss.xml")!))
-    }
-
-    @Test func htmlPaywallIsRejected() {
-        let html = "<html><body>Subscribe to continue reading this article</body></html>"
-        let reason = NewsPaywall.rejectionReason(
-            url: URL(string: "https://www.nytimes.com/story")!,
-            status: 200,
-            contentType: "text/html",
-            body: Data(html.utf8)
-        )
-        #expect(reason != nil)
-        #expect(reason?.localizedCaseInsensitiveContains("paywall") == true)
-    }
-
-    @Test func rssFromPaywalledPublisherIsAllowed() {
-        let rss = """
-        <?xml version="1.0"?><rss version="2.0"><channel><title>Feed</title></channel></rss>
-        """
-        let reason = NewsPaywall.rejectionReason(
-            url: URL(string: "https://rss.nytimes.com/services/xml/rss/nyt/HomePage.xml")!,
-            status: 200,
-            contentType: "application/rss+xml",
-            body: Data(rss.utf8)
-        )
-        #expect(reason == nil)
-    }
-
-    @Test func parserReadsRssItemsWithLinks() {
-        let rss = """
-        <?xml version="1.0"?>
-        <rss version="2.0"><channel>
-        <item><title>Hello world</title><link>https://example.com/hello</link><description>Body</description></item>
-        </channel></rss>
-        """
-        let entries = NewsFeedParser.parse(
-            data: Data(rss.utf8),
-            sourceLabel: "Example",
-            fallbackPageURL: URL(string: "https://example.com/feed")!
-        )
-        #expect(entries.count == 1)
-        #expect(entries[0].title == "Hello world")
-        #expect(entries[0].sourceURL == "https://example.com/hello")
-    }
-
-    @Test func refreshFailsPaywalledURL() async throws {
-        let client = StubNewsClient(response: NewsHTTPResponse(
-            status: 200,
-            contentType: "text/html",
-            body: Data("<html>This article is for subscribers only</html>".utf8)
-        ))
-        let spec = NewsReaderSpec(
-            name: "Test",
-            topics: [],
-            sources: [NewsSource(label: "NYT", url: "https://www.nytimes.com/story")]
-        )
-        do {
-            _ = try await NewsReaderRefresh.validateAndFetch(spec: spec, client: client)
-            Issue.record("expected paywall failure")
-        } catch let error as NewsReaderError {
-            guard case .paywalled = error else {
-                Issue.record("expected paywalled, got \(error)")
-                return
-            }
-        }
-    }
-
-    @Test func refreshReturnsLinkedItemsCapped() async throws {
-        let rss = """
-        <?xml version="1.0"?><rss><channel>
-        <item><title>One</title><link>https://example.com/1</link></item>
-        <item><title>Two</title><link>https://example.com/2</link></item>
-        <item><title>Three</title><link>https://example.com/3</link></item>
-        </channel></rss>
-        """
-        let client = StubNewsClient(response: NewsHTTPResponse(
-            status: 200,
-            contentType: "application/rss+xml",
-            body: Data(rss.utf8)
-        ))
-        let spec = NewsReaderSpec(
-            name: "Cap",
-            topics: [],
-            sources: [NewsSource(label: "Ex", url: "https://example.com/rss.xml")],
-            maxCount: 2
-        )
-        let items = try await NewsReaderRefresh.validateAndFetch(spec: spec, client: client)
-        #expect(items.count == 2)
-        #expect(items.allSatisfy { !$0.sourceURL.isEmpty })
-    }
-
-    @Test func googleNewsHomepageMapsToRSS() {
-        let mapped = NewsSourceURL.canonicalFetchURL(URL(string: "https://news.google.com/")!)
-        #expect(mapped.host == "news.google.com")
-        #expect(mapped.path == "/rss")
-        let already = NewsSourceURL.canonicalFetchURL(
-            URL(string: "https://news.google.com/rss?hl=en-US")!
-        )
-        #expect(already.path.contains("rss"))
-    }
-
-    @Test func refreshParsesGoogleNewsHomepageViaRSS() async throws {
-        let rss = """
-        <?xml version="1.0"?><rss version="2.0"><channel>
-        <item><title>World headline</title><link>https://news.google.com/articles/abc</link><description>Summary bit</description></item>
-        </channel></rss>
-        """
-        let client = StubNewsClient(response: NewsHTTPResponse(
-            status: 200,
-            contentType: "application/rss+xml",
-            body: Data(rss.utf8)
-        ))
-        let spec = NewsReaderSpec(
-            name: "Google",
-            topics: [],
-            sources: [NewsSource(label: "Google News", url: "https://news.google.com")],
-            mode: .summaries,
-            maxCount: 10
-        )
-        let items = try await NewsReaderRefresh.validateAndFetch(spec: spec, client: client)
-        #expect(items.count == 1)
-        #expect(items[0].title == "World headline")
-        #expect(items[0].sourceURL.contains("news.google.com"))
-        #expect(NewsReaderRefresh.digest(from: items).contains("World headline"))
-    }
-
-    @Test func liveGoogleNewsRSSHasLinkedSummaries() async throws {
-        let spec = NewsReaderSpec(
-            name: "Google live",
-            topics: [],
-            sources: [NewsPresetSource.googleNews.source],
-            mode: .summaries,
-            maxCount: 8
-        )
-        let items = try await NewsReaderRefresh.validateAndFetch(
-            spec: spec,
-            client: URLSessionNewsHTTPClient()
-        )
-        #expect(!items.isEmpty)
-        #expect(items.allSatisfy { !$0.sourceURL.isEmpty && !$0.title.isEmpty })
-        #expect(!NewsReaderRefresh.digest(from: items).isEmpty)
-    }
-
-    private struct StubNewsClient: NewsHTTPClient {
-        let response: NewsHTTPResponse
-        func get(url: URL) async throws -> NewsHTTPResponse { response }
-    }
-}
diff --git a/packages/Structure/Tests/StructureTests/PluginSkillDraftTests.swift b/packages/Structure/Tests/StructureTests/PluginSkillDraftTests.swift
new file mode 100644
index 00000000..a2bb3eb3
--- /dev/null
+++ b/packages/Structure/Tests/StructureTests/PluginSkillDraftTests.swift
@@ -0,0 +1,84 @@
+import Foundation
+import Testing
+@testable import Structure
+
+@Suite struct PluginSkillDraftTests {
+    @Test func newsGoalIsCustomCapabilityNotACoreProduct() {
+        var draft = PluginSkillDraft(goal: "Fetch tech news headlines daily")
+        PluginSkillDraftPlanner.applyGoal(draft.goal, to: &draft, existingPluginIDs: [])
+        #expect(draft.plannedKind == .customCapability)
+    }
+
+    @Test func infersSlackConnectorFromGoal() {
+        var draft = PluginSkillDraft(goal: "Send messages in Slack from Messaging")
+        PluginSkillDraftPlanner.applyGoal(draft.goal, to: &draft, existingPluginIDs: [])
+        #expect(draft.plannedKind == .messagingConnector)
+        #expect(draft.inferredConnectorVendor == .slack)
+        #expect(draft.examples.count >= 1)
+    }
+
+    @Test func infersCustomCapabilityFromGenericGoal() {
+        var draft = PluginSkillDraft(goal: "Summarize my clipboard when I ask")
+        PluginSkillDraftPlanner.applyGoal(draft.goal, to: &draft, existingPluginIDs: [])
+        #expect(draft.plannedKind == .customCapability)
+    }
+
+    @Test func skillMarkdownIncludesPurposeAndExamples() {
+        var draft = PluginSkillDraft(
+            goal: "Do something",
+            purpose: "Help with tasks",
+            triggers: [.chat],
+            examples: [
+                PluginSkillDraft.Example(userSays: "run it", pluginDoes: "returns a result"),
+            ],
+            pluginName: "my-plugin"
+        )
+        let markdown = draft.skillMarkdown()
+        #expect(markdown.contains("my-plugin"))
+        #expect(markdown.contains("Help with tasks"))
+        #expect(markdown.contains("run it"))
+    }
+
+    @Test func makeFromSkillDraftBuildsConnectorInput() throws {
+        var draft = PluginSkillDraft(
+            goal: "Slack connector",
+            purpose: "Messaging",
+            examples: [
+                PluginSkillDraft.Example(userSays: "hi", pluginDoes: "send"),
+            ],
+            pluginName: "slack-connector-1"
+        )
+        let input = try PluginFactoryCreateInput.makeFromSkillDraft(draft)
+        #expect(input.pluginType == .connector)
+        #expect(input.vendor == .slack)
+        #expect(input.pluginID == "slack-connector-1")
+        #expect(input.skillMarkdown != nil)
+    }
+
+    @Test func makeFromSkillDraftBuildsCustomInput() throws {
+        var draft = PluginSkillDraft(
+            goal: "Summarize text",
+            purpose: "Summarize",
+            examples: [
+                PluginSkillDraft.Example(userSays: "summarize", pluginDoes: "returns summary"),
+            ],
+            pluginName: "summarizer"
+        )
+        let input = try PluginFactoryCreateInput.makeFromSkillDraft(draft)
+        #expect(input.pluginType == .custom)
+        #expect(input.vendor == nil)
+        #expect(input.pluginID == "summarizer")
+    }
+
+    @Test func messagingConnectorDisallowsScheduleTrigger() {
+        let allowed = PluginSkillDraftPlanner.availableTriggers(for: .messagingConnector)
+        #expect(allowed == Set([.chat, .messaging, .mention]))
+        var draft = PluginSkillDraft(
+            goal: "Slack connector",
+            triggers: [.schedule, .chat, .messaging],
+            pluginName: "slack-1"
+        )
+        PluginSkillDraftPlanner.sanitizeTriggers(in: &draft)
+        #expect(draft.triggers == Set([.chat, .messaging]))
+    }
+}
diff --git a/packages/Structure/Tests/StructureTests/ScriptExecContractTests.swift b/packages/Structure/Tests/StructureTests/ScriptExecContractTests.swift
new file mode 100644
index 00000000..c71db5c2
--- /dev/null
+++ b/packages/Structure/Tests/StructureTests/ScriptExecContractTests.swift
@@ -0,0 +1,50 @@
+import Foundation
+import Structure
+import Testing
+
+@Suite struct ScriptExecContractTests {
+    @Test func protocolJSONLoadsAndMatchesRules() throws {
+        let document = try ScriptExecContractStore.loadProtocol()
+        #expect(document.version == 1)
+        #expect(document.runtime.language == "go")
+        #expect(document.review.failFast)
+        #expect(document.review.checks.count == 4)
+        #expect(document.rules.guestHasNoNetwork)
+        #expect(document.output.fields["content"]?.purpose.contains("plain-text") == true)
+        #expect(document.pluginFactory.manifest.hostCreatesManifest)
+        #expect(document.pluginFactory.builder.connectorTestInputUsesHopsArray)
+        #expect(document.pluginFactory.review.compilationSuccessNotApproval)
+    }
+
+    @Test func pluginFactoryPromptsReferenceContractJSON() {
+        let builder = ScriptExecContractPrompts.pluginFactoryBuilderGuide()
+        let reviewer = ScriptExecContractPrompts.pluginFactoryReviewerGuide()
+        #expect(builder.contains("plugin_factory"))
+        #expect(builder.contains("--- script-exec-contract.json ---"))
+        #expect(reviewer.contains("plugin_factory.review"))
+        #expect(reviewer.contains("If a guest rule is not in the JSON"))
+    }
+
+    @Test func fingerprintMatchesGeneratedFile() throws {
+        #expect(try ScriptExecContractStore.computeFingerprint() == ScriptExecContractFingerprint.sha256)
+        #expect(ScriptExecContractFingerprint.sourceFiles == ScriptExecContractStore.fingerprintSources)
+    }
+
+    @Test func bundledContractSatisfiesItsSchema() throws {
+        try ScriptExecContractIntegrity.validateBundledGraph()
+    }
+
+    @Test func reviewerGuideDumpsCanonicalJSON() throws {
+        let guide = ScriptExecContractPrompts.reviewerGuide()
+        #expect(guide.contains("If a rule is not in the JSON"))
+        #expect(guide.contains("--- script-exec-contract.json ---"))
+        #expect(guide.contains(try ScriptExecContractStore.loadProtocolText()))
+        #expect(guide.contains("--- \(GuestContract.Schema.envelopeList.rawValue) ---"))
+    }
+
+    @Test func builderGuideDumpsWireSchemas() throws {
+        let guide = ScriptExecContractPrompts.builderGuide()
+        #expect(guide.contains("--- \(GuestContract.Schema.hopEvent.rawValue) ---"))
+        #expect(guide.contains("--- \(GuestContract.Schema.guestRuntime.rawValue) ---"))
+    }
+}
diff --git a/readme.md b/readme.md
index e02a8bc4..b8b12621 100644
--- a/readme.md
+++ b/readme.md
@@ -10,7 +10,7 @@ A native Swift macOS 27 desktop agent harness: chat with LLM providers, run isol
 |------|-------------|
 | **Chat** | Multi-tab conversations with OpenAI, Gemini, and other configured models |
 | **Tools (MCP)** | Model Context Protocol tool host inside the headless daemon |
-| **Scripts** | Agent-generated Python executed in isolated Docker containers. Includes a secondary agent code reviewer and approvals flow. |
+| **Scripts** | Agent-generated Go executed in isolated Docker containers. Includes a secondary agent code reviewer and approvals flow. |
 | **Plugin factory** | LLM-assisted creation of versioned, reviewed connector plugins |
 | **Jobs** | Scheduled and deferred tool/agent runs that survive app quit |
 | **Messaging** | Connector plugins (e.g. Slack) with threads, history, and live sync |
@@ -35,14 +35,14 @@ A native Swift macOS 27 desktop agent harness: chat with LLM providers, run isol
         └────────────────┘        └───────────┬────────────┘
                                                 │
                                     ┌───────────▼────────────┐
-                                    │ Python guest containers  │
+                                    │ Go worker containers     │
                                     │ --network none         │
                                     └────────────────────────┘
 ```
 
 - **UI** is a client: it does not own agent turns or MCP when the daemon is up.
 - **Daemon** (`derrickd`) is the single owner of OS notifications and in-process Agent/Job/MCP modules.
-- **Docker** runs untrusted Python for `script_exec`, plugin factory builds, and approved plugin invocations.
+- **Docker** runs untrusted Go for `script_exec`, plugin factory builds, and approved plugin invocations.
 
 See [docs/adr-headless-backend.md](docs/adr-headless-backend.md) and [docs/services-plan.md](docs/services-plan.md).
 
@@ -50,10 +50,12 @@ See [docs/adr-headless-backend.md](docs/adr-headless-backend.md) and [docs/servi
 
 Derrick treats model output and guest code as untrusted.
 
-### Docker sandbox (Python guest runtime)
+### Docker sandbox (Go worker runtime)
 
-- Guest programs run in `python:3.14.7` containers with **`--network none`**.
-- No sockets, urllib/requests, subprocess, or credentials inside the guest.
+- **`script_exec`, plugins, web crawl, and file extract** share one Go worker image `derrick-worker:go-v1` (digest-pinned, `--network none` for guests).
+- Plugin and script sources are compiled **inside the worker container** (Go 1.27.1 in the image). Users only need Docker Desktop.
+- Canonical I/O types live in `packages/Structure/Sources/Contract/Resources/schemas/` and are mirrored to `workers/go/internal/contract/schemas/`.
+- No net/http, subprocess, filesystem access, or credentials inside the guest.
 - The host dispatches `http.request` envelopes, attaches secrets, and enforces egress policy.
 - Historical Swift guest notes: [docs/adr-swift-script-runtime.md](docs/adr-swift-script-runtime.md).
 
@@ -65,7 +67,7 @@ Before `script_exec` writes to disk, a **configured LLM reviewer** checks:
 - No secret literals in source
 - Safe handling of fetched content (no raw HTML leakage unless requested)
 
-Instructions live in `ui/SharedAgentRuntime/Resources/script_reviewer_instructions.md`. A static **Python verifier** also rejects forbidden APIs.
+Rules live in `packages/Structure/Sources/Contract/Resources/contracts/script-exec-contract.json` (same pattern as connector plugins). A static **Go verifier** also rejects forbidden APIs.
 
 ### Egress & network
 
diff --git a/scripts/generate-script-exec-contract.swift b/scripts/generate-script-exec-contract.swift
new file mode 100755
index 00000000..4c1995ce
--- /dev/null
+++ b/scripts/generate-script-exec-contract.swift
@@ -0,0 +1,121 @@
+#!/usr/bin/env swift
+import CryptoKit
+import Foundation
+
+/// Regenerates `ScriptExecContract.generated.swift` from bundled script_exec JSON.
+/// `--check` exits 1 when the committed fingerprint does not match the JSON files
+/// or when the JSON no longer satisfies the bundled schemas.
+
+let repoRoot = URL(fileURLWithPath: CommandLine.arguments[0])
+    .resolvingSymlinksInPath()
+    .deletingLastPathComponent()
+    .deletingLastPathComponent()
+
+let resources = repoRoot
+    .appendingPathComponent("packages/Structure/Sources/Contract/Resources")
+
+let sources: [(relative: String, url: URL)] = [
+    "schemas/script-exec-contract.schema.json",
+    "schemas/guest-runtime.schema.json",
+    "schemas/hop-event.schema.json",
+    "schemas/envelope-list.schema.json",
+    "contracts/script-exec-contract.json",
+].map { relative in
+    (relative, resources.appendingPathComponent(relative))
+}
+
+let generatedURL = repoRoot
+    .appendingPathComponent("packages/Structure/Sources/Contract/Generated/ScriptExecContract.generated.swift")
+
+func jsonObject(_ url: URL) throws -> [String: Any] {
+    let data = try Data(contentsOf: url)
+    guard let object = try JSONSerialization.jsonObject(with: data) as? [String: Any] else {
+        throw ScriptError("\(url.lastPathComponent) is not a JSON object.")
+    }
+    return object
+}
+
+func requireKeys(_ object: [String: Any], _ keys: [String], file: String) throws {
+    for key in keys where object[key] == nil {
+        throw ScriptError("\(file) is missing required key \(key).")
+    }
+}
+
+func validateGraph() throws {
+    let contractSchema = try jsonObject(resources.appendingPathComponent("schemas/script-exec-contract.schema.json"))
+    let contract = try jsonObject(resources.appendingPathComponent("contracts/script-exec-contract.json"))
+    try requireKeys(contract, contractSchema["required"] as? [String] ?? [], file: "script-exec-contract.json")
+    let rulesSchema = (contractSchema["properties"] as? [String: Any])?["rules"] as? [String: Any]
+    try requireKeys(
+        contract["rules"] as? [String: Any] ?? [:],
+        rulesSchema?["required"] as? [String] ?? [],
+        file: "script-exec-contract.json rules"
+    )
+    let checks = (contract["review"] as? [String: Any])?["checks"] as? [[String: Any]] ?? []
+    if checks.isEmpty {
+        throw ScriptError("script-exec-contract.json review.checks must not be empty.")
+    }
+    let pluginFactorySchema = (contractSchema["properties"] as? [String: Any])?["plugin_factory"] as? [String: Any]
+    try requireKeys(
+        contract["plugin_factory"] as? [String: Any] ?? [:],
+        pluginFactorySchema?["required"] as? [String] ?? [],
+        file: "script-exec-contract.json plugin_factory"
+    )
+}
+
+func fingerprint() throws -> String {
+    var joined = Data()
+    for source in sources {
+        let data = try Data(contentsOf: source.url)
+        joined.append(Data(source.relative.utf8))
+        joined.append(0)
+        joined.append(data)
+        joined.append(0)
+    }
+    return SHA256.hash(data: joined).map { String(format: "%02x", $0) }.joined()
+}
+
+func generatedSource(hash: String) -> String {
+    """
+    // Automatically generated by scripts/generate-script-exec-contract.swift. DO NOT EDIT.
+
+    /// SHA-256 of script_exec protocol JSON and schemas. `swift test` fails when this is stale.
+    public enum ScriptExecContractFingerprint: Sendable {
+        public static let sha256 = "\(hash)"
+        public static let sourceFiles: [String] = [
+    \(sources.map { "        \"\($0.relative)\"," }.joined(separator: "\n"))
+        ]
+    }
+
+    """
+}
+
+struct ScriptError: Error, CustomStringConvertible {
+    let description: String
+    init(_ description: String) { self.description = description }
+}
+
+do {
+    try validateGraph()
+} catch {
+    fputs("\(error)\n", stderr)
+    exit(1)
+}
+
+let hash = try fingerprint()
+let check = CommandLine.arguments.contains("--check")
+if check {
+    let existing = try String(contentsOf: generatedURL, encoding: .utf8)
+    if !existing.contains("public static let sha256 = \"\(hash)\"") {
+        fputs("script_exec contract fingerprint is stale. Run scripts/generate-script-exec-contract.swift\n", stderr)
+        exit(1)
+    }
+    exit(0)
+}
+
+try FileManager.default.createDirectory(
+    at: generatedURL.deletingLastPathComponent(),
+    withIntermediateDirectories: true
+)
+try generatedSource(hash: hash).write(to: generatedURL, atomically: true, encoding: .utf8)
+print("Wrote \(generatedURL.path) sha256=\(hash)")
diff --git a/scripts/record-docker-image-digests.sh b/scripts/record-docker-image-digests.sh
new file mode 100755
index 00000000..4642aa41
--- /dev/null
+++ b/scripts/record-docker-image-digests.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+# Builds the unified Go worker image and updates the pinned digest in Structure.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
+
+IMAGE="derrick-worker:go-v1"
+docker build -f docker/worker/Dockerfile -t "$IMAGE" .
+
+DIGEST="$(docker image inspect --format '{{.Id}}' "$IMAGE")"
+OUT="packages/Structure/Sources/DockerRunnerXPC/DockerProductImageDigests.generated.swift"
+
+cat >"$OUT" <<EOF
+import Foundation
+
+/// Generated by scripts/record-docker-image-digests.sh — do not edit.
+public enum DockerProductImageDigests: Sendable {
+    public static let worker = DockerImageDigest(rawValue: "$DIGEST")
+}
+EOF
+
+echo "Recorded worker digest $DIGEST"
diff --git a/scripts/reset-local-state.sh b/scripts/reset-local-state.sh
new file mode 100755
index 00000000..fb845c65
--- /dev/null
+++ b/scripts/reset-local-state.sh
@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+APP_GROUP="$HOME/Library/Group Containers/VUSK4B2YKQ.derrick.shared"
+
+echo "==> Quit Derrick before resetting local state."
+echo "==> This removes all local SQLite data (chats, plugins, messaging, credentials in DB)."
+echo "==> Keychain plugin secrets are not removed."
+
+removed_dbs=0
+if [[ -d "$APP_GROUP" ]]; then
+  while IFS= read -r db; do
+    rm -f "$db" "${db}-wal" "${db}-shm"
+    echo "removed $(basename "$db") at ${db%/*}"
+    removed_dbs=$((removed_dbs + 1))
+  done < <(find "$APP_GROUP" -name 'derrick.sqlite3' 2>/dev/null)
+fi
+
+if [[ "$removed_dbs" -eq 0 ]]; then
+  echo "no derrick.sqlite3 files found under $APP_GROUP"
+fi
+
+if command -v docker >/dev/null 2>&1; then
+  echo "==> Removing Derrick runtime containers"
+  for filter in 'name=derrick-guest-runtime' 'name=derrick-swift-runtime' 'label=app.derrick=runtime'; do
+    ids="$(docker ps -aq --filter "$filter" || true)"
+    if [[ -n "$ids" ]]; then
+      docker rm -f $ids >/dev/null 2>&1 || true
+    fi
+  done
+
+  echo "==> Removing obsolete guest images (Python / legacy guest-runtime)"
+  for image in \
+    'derrick-guest-runtime:python-v1' \
+    'python:3.14.7'; do
+    if docker image inspect "$image" >/dev/null 2>&1; then
+      docker rmi -f "$image" >/dev/null
+      echo "removed image $image"
+    fi
+  done
+else
+  echo "docker not available — skipped container/image cleanup"
+fi
+
+echo
+echo "Done. Reopen Derrick from $ROOT (go-workers) to recreate an empty database."
+echo "Policy rules seed automatically on first UI launch."
diff --git a/scripts/sync-guest-contract-schemas.sh b/scripts/sync-guest-contract-schemas.sh
new file mode 100755
index 00000000..daa1d819
--- /dev/null
+++ b/scripts/sync-guest-contract-schemas.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# Copies canonical guest and worker-product JSON schemas from Structure into the Go worker module.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+SRC="$ROOT/packages/Structure/Sources/Contract/Resources/schemas"
+DST="$ROOT/workers/go/internal/contract/schemas"
+
+mkdir -p "$DST"
+rsync -a --delete "$SRC/" "$DST/"
+echo "Synced guest contract schemas to $DST"
diff --git a/scripts/verify-guest-contract-schemas-in-sync.sh b/scripts/verify-guest-contract-schemas-in-sync.sh
new file mode 100755
index 00000000..0dbce088
--- /dev/null
+++ b/scripts/verify-guest-contract-schemas-in-sync.sh
@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Fails CI when canonical Structure schemas (guest + worker product) drift from the Go worker copy.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+SRC="$ROOT/packages/Structure/Sources/Contract/Resources/schemas"
+DST="$ROOT/workers/go/internal/contract/schemas"
+
+if ! diff -qr "$SRC" "$DST" >/dev/null; then
+  echo "Guest contract schemas are out of sync. Run: scripts/sync-guest-contract-schemas.sh" >&2
+  diff -qr "$SRC" "$DST" >&2 || true
+  exit 1
+fi
+
+echo "Guest contract schemas are in sync."
diff --git a/ui/AgentService/AgentServiceExportedObject.swift b/ui/AgentService/AgentServiceExportedObject.swift
index 456bfa46..6336a224 100644
--- a/ui/AgentService/AgentServiceExportedObject.swift
+++ b/ui/AgentService/AgentServiceExportedObject.swift
@@ -67,7 +67,7 @@ final class AgentServiceExportedObject: NSObject, AgentServiceXPC {
                 service: .agent,
                 status: .ok,
                 detail: "AgentService ready (DB+\(leaf))",
-                guestRuntimeImage: DerrickProcessRole.isDaemon ? DerrickGuestRuntime.pythonGuestDockerImage : nil
+                guestRuntimeImage: DerrickProcessRole.isDaemon ? DerrickGuestRuntime.guestDockerImage : nil
             )
             let data = (try? AgentServiceXPCCodec.encodeHealth(report)) ?? Data("{}".utf8)
             reply(data as NSData)
diff --git a/ui/AgentService/AgentServiceTurnHost.swift b/ui/AgentService/AgentServiceTurnHost.swift
index 84e9efbc..e4578ea0 100644
--- a/ui/AgentService/AgentServiceTurnHost.swift
+++ b/ui/AgentService/AgentServiceTurnHost.swift
@@ -223,7 +223,6 @@ actor AgentServiceTurnHost {
                 LLMModelSettings(repository: repo)
             }
             helperModelSettings = settings
-            await EgressAllowlistService.shared.configure(repository: repo)
             await ContentSensitivityGrantService.shared.configure(repository: repo)
             await UsageLimitsService.shared.configure(repository: repo)
             await ContainerLifecycleSettingsService.shared.configure(repository: repo)
diff --git a/ui/JobKeepAlive/DaemonModuleBootstrap.swift b/ui/JobKeepAlive/DaemonModuleBootstrap.swift
index dfae72f2..85956545 100644
--- a/ui/JobKeepAlive/DaemonModuleBootstrap.swift
+++ b/ui/JobKeepAlive/DaemonModuleBootstrap.swift
@@ -76,9 +76,6 @@ enum DaemonModuleBootstrap {
             Task {
                 await prewarmGuestRuntimeImage()
             }
-            Task {
-                await startWebCrawlerImageInBackground()
-            }
         } catch {
             fputs("[derrickd] MCP module bootstrap failed: \(error.localizedDescription)\n", stderr)
         }
@@ -102,7 +99,7 @@ enum DaemonModuleBootstrap {
     }
 
     /// Remove leftover runtime containers before the job scheduler starts.
-    /// Guest image pull stays in the background so a cold Python pull does not block jobs.
+    /// Guest image pull stays in the background so a cold worker image pull does not block jobs.
     private static func sweepEmbeddedDockerLeftovers() async {
         guard DerrickProcessRole.isDaemon else { return }
         do {
@@ -127,14 +124,4 @@ enum DaemonModuleBootstrap {
         }
     }
 
-    /// Does not block jobs or chat. A crawl that arrives during this build waits on the same task.
-    private static func startWebCrawlerImageInBackground() async {
-        guard DerrickProcessRole.isDaemon else { return }
-        do {
-            try await MCPServiceDockerHelperRunner.shared.ensureWebCrawlerImage()
-            fputs("[derrickd] web crawler image ready\n", stderr)
-        } catch {
-            fputs("[derrickd] web crawler image background build skipped: \(error.localizedDescription)\n", stderr)
-        }
-    }
 }
diff --git a/ui/JobService/MessagingAgentTurnClient.swift b/ui/JobService/MessagingAgentTurnClient.swift
index 461a1e49..12e260b7 100644
--- a/ui/JobService/MessagingAgentTurnClient.swift
+++ b/ui/JobService/MessagingAgentTurnClient.swift
@@ -11,7 +11,7 @@ enum MessagingAgentTurnClient {
         let profile = try await resolveProfile(handle: route.profileHandle, repository: repository)
         let model = (try? JSONDecoder().decode(LLMModelChoice.self, from: profile.modelJSON))
             ?? .defaultHelperModel
-        let apiKey = await resolveAPIKey(for: model) ?? ""
+        let apiKey = await LLMProviderCredentialGate.resolveAPIKey(for: model) ?? ""
         let profileContextJSON = try JSONEncoder().encode(AgentProfileTurnContext(profile: profile))
         let sessionID = MessagingAgentSessionID.make(
             pluginID: route.pluginID,
@@ -60,14 +60,6 @@ enum MessagingAgentTurnClient {
         throw MessagingAgentTurnClientError.profileUnavailable(handle)
     }
 
-    @MainActor
-    private static func resolveAPIKey(for model: LLMModelChoice) -> String? {
-        AppSecretResolver().resolve(
-            account: model.provider.secretAccount,
-            environmentKeys: model.provider.apiKeyEnvironmentKeys
-        )
-    }
-
     private static func sendConnectorMessage(
         route: MessagingAgentRoute,
         text: String,
diff --git a/ui/MCPService/MCPServiceDockerHelperRunner.swift b/ui/MCPService/MCPServiceDockerHelperRunner.swift
index 5ed26f9c..b623facf 100644
--- a/ui/MCPService/MCPServiceDockerHelperRunner.swift
+++ b/ui/MCPService/MCPServiceDockerHelperRunner.swift
@@ -63,17 +63,14 @@ final class MCPServiceDockerHelperRunner: @unchecked Sendable {
         await DerrickDockerOrphanSweeper.sweep(executor: makeStdinCLIExecutor())
     }
 
-    /// Prewarm the shared offline guest runtime image.
+    /// Prewarm the shared Go worker image used by script_exec and plugin.invoke.
     func prewarmGuestRuntime() async throws {
-        try await OneshotDockerContainer.ensurePulledImage(
-            DerrickGuestRuntime.pythonGuestDockerImage,
-            executor: makeStdinCLIExecutor()
-        )
+        try await WorkerImageGate.shared.ensureReady(executor: makeStdinCLIExecutor())
     }
 
-    /// Build the crawler image in the background. Joins an in-flight build if one exists.
+    /// Legacy alias — same worker image as `prewarmGuestRuntime`.
     func ensureWebCrawlerImage() async throws {
-        try await WebCrawlerImageGate.shared.ensureReady(executor: makeStdinCLIExecutor())
+        try await prewarmGuestRuntime()
     }
 
     var hasPeerEndpoint: Bool {
diff --git a/ui/MCPService/MCPServiceScriptReviewer.swift b/ui/MCPService/MCPServiceScriptReviewer.swift
index 9a1e4986..7da7ba47 100644
--- a/ui/MCPService/MCPServiceScriptReviewer.swift
+++ b/ui/MCPService/MCPServiceScriptReviewer.swift
@@ -20,9 +20,8 @@ struct MCPServiceScriptReviewer: ScriptReviewer {
     }
 
     func review(_ args: ScriptExecutionArguments) async throws -> ScriptReviewOutcome {
-        guard let apiKey = MCPServiceCallContext.shared.helperAPIKey,
-              !apiKey.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
-        else {
+        let selected = resolveSelectedModel()
+        guard let apiKey = await resolveAPIKey(for: selected) else {
             throw NSError(
                 domain: "MCPService",
                 code: 404,
@@ -30,7 +29,6 @@ struct MCPServiceScriptReviewer: ScriptReviewer {
             )
         }
 
-        let selected = resolveSelectedModel()
         do {
             return try await review(args, model: selected, apiKey: apiKey)
         } catch {
@@ -38,7 +36,7 @@ struct MCPServiceScriptReviewer: ScriptReviewer {
                 "[MCPService] reviewer model \(selected.label) failed: \(error.localizedDescription); trying defaults\n",
                 stderr
             )
-            if let fallback = await fallbackReview(args: args, apiKey: apiKey, excluding: selected) {
+            if let fallback = await fallbackReview(args: args, excluding: selected) {
                 return fallback
             }
             throw error
@@ -108,12 +106,12 @@ struct MCPServiceScriptReviewer: ScriptReviewer {
 
     private func fallbackReview(
         args: ScriptExecutionArguments,
-        apiKey: String,
         excluding: ReviewerModel
     ) async -> ScriptReviewOutcome? {
         var candidates: [ReviewerModel] = [Self.defaultModel, Self.secondaryDefault]
         candidates.removeAll { $0 == excluding }
         for candidate in candidates {
+            guard let apiKey = await resolveAPIKey(for: candidate) else { continue }
             do {
                 let outcome = try await review(args, model: candidate, apiKey: apiKey)
                 fputs("[MCPService] fallback reviewer succeeded model=\(candidate.label)\n", stderr)
@@ -127,6 +125,19 @@ struct MCPServiceScriptReviewer: ScriptReviewer {
         }
         return nil
     }
+
+    private func resolveAPIKey(for model: ReviewerModel) async -> String? {
+        await LLMProviderCredentialGate.resolveAPIKey(for: llmModelChoice(from: model))
+    }
+
+    private func llmModelChoice(from model: ReviewerModel) -> LLMModelChoice {
+        switch model {
+        case .openai(let openAIModel):
+            return .openai(openAIModel)
+        case .gemini(let geminiModel):
+            return .gemini(geminiModel)
+        }
+    }
 }
 
 /// Process-wide slots for the current MCPService tool call (handlers may not inherit TaskLocal).
diff --git a/ui/MCPService/MCPServiceToolHost.swift b/ui/MCPService/MCPServiceToolHost.swift
index b44967f9..d3aa0aff 100644
--- a/ui/MCPService/MCPServiceToolHost.swift
+++ b/ui/MCPService/MCPServiceToolHost.swift
@@ -42,7 +42,7 @@ actor MCPServiceToolHost {
             LLMModelThinkingSettings(repository: repo)
         }
         await factoryThinkingSettings.loadSettings()
-        let factoryExecutor = PythonPluginFactoryDockerExecutor(
+        let factoryExecutor = GoPluginFactoryDockerExecutor(
             executor: MCPServiceDockerHelperRunner.shared.makeStdinCLIExecutor()
         )
         let webCrawlerExecutor = WebCrawlerDockerExecutor(
@@ -67,10 +67,6 @@ actor MCPServiceToolHost {
                     await WorkflowProgressPublisher.publish(stage: "factory", message: progress)
                 }
             },
-            apiKeyProvider: {
-                MCPServiceCallContext.shared.helperAPIKey
-                    ?? TurnProcessContext.effectiveAPIKey
-            }
         )
         let made = try await MCPLocalBridge.make { server in
             await server.registerScriptExecutionTool(
@@ -233,32 +229,6 @@ actor MCPServiceToolHost {
                 message: "Tool \(toolName) is owned by AgentService, not MCPService."
             )
         }
-        if toolName == AllowedMCPTool.webCrawl.rawValue,
-           !EffectorAdmissionPolicy.allowsSyncWebCrawl(
-               context: EffectorAdmissionPolicy.parseContextJSON(request.executionContextJSON)
-                   ?? legacyExecutionContext(from: request),
-               principal: request.principal
-           ) {
-            let outcome = ToolExecutionOutcome.failure(
-                status: .blocked,
-                stage: .validation,
-                diagnostics: [
-                    ToolExecutionOutcome.Diagnostic(
-                        code: "web_crawl_requires_notification",
-                        message: "web.crawl must be submitted through jobs_create so the result can arrive in a notification banner."
-                    )
-                ],
-                retry: ToolExecutionOutcome.Retry(allowed: false)
-            )
-            return MCPToolCallResultDTO(
-                requestID: request.requestID,
-                ok: true,
-                isError: true,
-                text: (try? outcome.encodedJSON()) ?? "",
-                message: "Submit web.crawl through jobs_create for notification delivery."
-            )
-        }
-
         let sessionKey: MemorySessionKey
         switch request.principal {
         case .agent(let sessionID, let agentID):
diff --git a/ui/SharedAgentRuntime/Conversation/ConversationModel.swift b/ui/SharedAgentRuntime/Conversation/ConversationModel.swift
index 95e02e85..e2ed82c1 100644
--- a/ui/SharedAgentRuntime/Conversation/ConversationModel.swift
+++ b/ui/SharedAgentRuntime/Conversation/ConversationModel.swift
@@ -266,7 +266,7 @@ final class ConversationModel {
         let interceptor = makeContentPolicyInterceptor()
         let orchestrator = self.orchestrator
         let workerModel = helperModelSettings.workerAgentModel
-        let workerApiKey = resolveAPIKey(for: workerModel, turnFallback: apiKey) ?? apiKey
+        let workerApiKey = await LLMProviderCredentialGate.resolveAPIKey(for: workerModel) ?? apiKey
 
         let effectiveModel: LLMModelChoice
         let effectiveThinking: ModelThinkingOption?
@@ -593,21 +593,6 @@ final class ConversationModel {
         return DefaultPolicyInterceptor(policy: policy)
     }
 
-    /// API key for a helper/worker model: keychain/env for its provider, else the active turn key.
-    private func resolveAPIKey(for model: LLMModelChoice, turnFallback: String) -> String? {
-        if let key = AppSecretResolver().resolve(
-            account: model.provider.secretAccount,
-            environmentKeys: model.provider.apiKeyEnvironmentKeys
-        ), !key.isEmpty {
-            return key
-        }
-        if let turnKey = TurnProcessContext.effectiveAPIKey, !turnKey.isEmpty {
-            return turnKey
-        }
-        let trimmed = turnFallback.trimmingCharacters(in: .whitespacesAndNewlines)
-        return trimmed.isEmpty ? nil : trimmed
-    }
-
     /// In-process host for orchestration tools (`agents_*`, `jobs_*`). Not used for MCP effectors.
     /// `nonisolated`: tool handlers must not hop to MainActor while the turn awaits the MCP local bridge
     /// (that pattern deadlocks when runTurn is MainActor-isolated).
@@ -727,13 +712,14 @@ final class ConversationModel {
             wakePrompt: wakePrompt,
             description: description
         )
+        let providerAPIKey = await LLMProviderCredentialGate.resolveAPIKey(for: .defaultHelperModel)
         let request = try JobOrderBuilder.createJobRequest(
             from: input,
             principal: principal,
             source: .agent,
             sessionID: sessionID,
             agentID: agentID,
-            helperAPIKey: TurnProcessContext.effectiveAPIKey,
+            helperAPIKey: providerAPIKey,
             helperReviewerModelJSON: reviewerJSON
         )
         debugLog("[jobs_create] calling JobService createJob…")
@@ -787,13 +773,14 @@ final class ConversationModel {
             wakePrompt: wakePrompt,
             enabled: true
         )
+        let providerAPIKey = await LLMProviderCredentialGate.resolveAPIKey(for: .defaultHelperModel)
         let request = try JobOrderBuilder.createScheduleRequest(
             from: input,
             principal: principal,
             source: .agent,
             sessionID: sessionID,
             agentID: agentID,
-            helperAPIKey: TurnProcessContext.effectiveAPIKey,
+            helperAPIKey: providerAPIKey,
             helperReviewerModelJSON: reviewerJSON
         )
         let schedule = try await placer.createSchedule(request)
diff --git a/ui/SharedAgentRuntime/Conversation/ConversationPipeline.swift b/ui/SharedAgentRuntime/Conversation/ConversationPipeline.swift
index edd1d542..8a658c8e 100644
--- a/ui/SharedAgentRuntime/Conversation/ConversationPipeline.swift
+++ b/ui/SharedAgentRuntime/Conversation/ConversationPipeline.swift
@@ -122,11 +122,6 @@ struct ConversationPipeline<Client: ConversationStreamingClient & Sendable>: Sen
         if !toolInstructions.isEmpty {
             sections.append(toolInstructions)
         }
-        if !toolInstructions.contains("Python guest contract:") {
-            if let sdk = try? PromptResources.guestSDKForModel() {
-                sections.append(sdk)
-            }
-        }
         return sections.joined(separator: "\n\n")
     }
 
diff --git a/ui/SharedAgentRuntime/Conversation/ConversationPipelinePolicy.swift b/ui/SharedAgentRuntime/Conversation/ConversationPipelinePolicy.swift
index 8c8c64b3..406d88bf 100644
--- a/ui/SharedAgentRuntime/Conversation/ConversationPipelinePolicy.swift
+++ b/ui/SharedAgentRuntime/Conversation/ConversationPipelinePolicy.swift
@@ -877,7 +877,7 @@ extension ConversationPipeline {
     private static func longRunningToolProgressMessage(for toolName: String) -> String? {
         switch toolName {
         case AllowedMCPTool.webCrawl.rawValue:
-            return "Crawling vendor documentation. This may take a few minutes…"
+            return "Fetching web content. This may take a few minutes…"
         case AllowedMCPTool.pluginFactoryBuild.rawValue:
             return "Building the plugin (code generation, Docker tests, and safety review). This may take several minutes…"
         default:
diff --git a/ui/SharedAgentRuntime/Conversation/ProfileDelegateRunner.swift b/ui/SharedAgentRuntime/Conversation/ProfileDelegateRunner.swift
index 3a9f8666..38f040b8 100644
--- a/ui/SharedAgentRuntime/Conversation/ProfileDelegateRunner.swift
+++ b/ui/SharedAgentRuntime/Conversation/ProfileDelegateRunner.swift
@@ -40,7 +40,7 @@ enum ProfileDelegateRunner {
         let thinking = profileContext.thinkingJSON.flatMap {
             try? JSONDecoder().decode(ModelThinkingOption.self, from: $0)
         }
-        let apiKey = TurnProcessContext.effectiveAPIKey ?? ""
+        let apiKey = await LLMProviderCredentialGate.resolveAPIKey(for: model) ?? ""
 
         let delegateSessionKey = MemorySessionKey(
             sessionID: sessionKey.sessionID,
diff --git a/ui/SharedAgentRuntime/Job/JobNetworkPreflight.swift b/ui/SharedAgentRuntime/Job/JobNetworkPreflight.swift
index 540ea804..04547a72 100644
--- a/ui/SharedAgentRuntime/Job/JobNetworkPreflight.swift
+++ b/ui/SharedAgentRuntime/Job/JobNetworkPreflight.swift
@@ -5,9 +5,8 @@ import Plugin
 import PolicyUserInteraction
 import Structure
 
-/// Before a scheduled network tool runs, ensure hosts are allowlisted.
-/// Uncovered hosts use the HITL **banner** path (not live chat modals / schedule preflight).
-///
+/// Before a scheduled network tool runs, prompt only on blacklist hits.
+/// Public HTTPS is allowed by default; hard-blocked SSRF targets are denied without a prompt.
 public enum JobNetworkPreflight {
     public static func approveScriptNetworkIfNeeded(
         toolName: String,
@@ -30,6 +29,13 @@ public enum JobNetworkPreflight {
         }
         guard !hosts.isEmpty else { return }
 
+        let hardBlockPolicy = DefaultDestinationPolicy(allowedDomainSuffixes: [])
+        for host in hosts {
+            if hardBlockPolicy.isHardBlockedHostname(host) {
+                throw JobNetworkPreflightError.hardBlocked(host: host)
+            }
+        }
+
         let blacklist = try await repository.listEgressBlacklist()
         let exceptions = try await repository.listEgressBlacklistExceptions()
         for host in hosts {
@@ -40,13 +46,15 @@ public enum JobNetworkPreflight {
             ) else {
                 continue
             }
+            let argumentsJSON = blacklistArgumentsJSON(host: host, entry: entry, toolName: toolName)
             let decision = await HITLOfflineNetworkService.awaitDecision(
                 host: host,
                 toolName: toolName,
                 turnID: "job-\(jobID)",
                 isJobContext: true,
                 repository: repository,
-                timeoutNanoseconds: 300_000_000_000
+                timeoutNanoseconds: 300_000_000_000,
+                argumentsJSON: argumentsJSON
             )
             switch decision {
             case .approved, .approvedOnce:
@@ -62,83 +70,28 @@ public enum JobNetworkPreflight {
             }
         }
 
-        let suffixes = try await loadEnabledSuffixes(repository: repository)
-
-        let policy = DefaultDestinationPolicy(allowedDomainSuffixes: suffixes)
-        var uncovered: [String] = []
-        for host in hosts {
-            if policy.isHardBlockedHostname(host) {
-                throw JobNetworkPreflightError.hardBlocked(host: host)
-            }
-            if policy.isHostCoveredByAllowlist(host) {
-                continue
-            }
-            uncovered.append(host)
-        }
-        guard !uncovered.isEmpty else {
-            fputs(
-                "[JobNetworkPreflight] job=\(jobID) hosts covered count=\(hosts.count)\n",
-                stderr
-            )
-            return
-        }
-
         fputs(
-            "[JobNetworkPreflight] job=\(jobID) banner approval needed hosts=\(uncovered.joined(separator: ","))\n",
+            "[JobNetworkPreflight] job=\(jobID) ok hosts=\(hosts.count)\n",
             stderr
         )
-
-        var sessionGrants: [String] = []
-        var allowedSuffixes = suffixes
-        for host in uncovered {
-            let coverage = DefaultDestinationPolicy(allowedDomainSuffixes: allowedSuffixes)
-            if coverage.isHostCoveredByAllowlist(host) {
-                continue
-            }
-            // Session grants from earlier Allow Once in this preflight (suffix-scoped).
-            let sessionPolicy = DefaultDestinationPolicy(allowedDomainSuffixes: [])
-            sessionPolicy.grantSessionHosts(sessionGrants)
-            if sessionPolicy.isHostCoveredByAllowlist(host) {
-                continue
-            }
-            let decision = await HITLOfflineNetworkService.awaitDecision(
-                host: host,
-                toolName: toolName,
-                turnID: "job-\(jobID)",
-                isJobContext: true,
-                repository: repository,
-                timeoutNanoseconds: 300_000_000_000
-            )
-            switch decision {
-            case .approvedPermanently(let actor):
-                let suffix = EgressHostExtractor.permanentSuffix(for: host)
-                try await repository.saveEgressAllowedDomainSuffix(
-                    EgressAllowedDomainSuffix(suffix: suffix, source: actor ?? "job-banner", enabled: true)
-                )
-                allowedSuffixes = try await loadEnabledSuffixes(repository: repository)
-                fputs(
-                    "[JobNetworkPreflight] always host=\(host) suffix=\(suffix) actor=\(actor ?? "?")\n",
-                    stderr
-                )
-            case .approved(let actor), .approvedOnce(let actor):
-                sessionGrants.append(host)
-                fputs(
-                    "[JobNetworkPreflight] once host=\(host) actor=\(actor ?? "?")\n",
-                    stderr
-                )
-            case .denied(let actor):
-                throw JobNetworkPreflightError.denied(host: host, actor: actor)
-            case .dismissed:
-                throw JobNetworkPreflightError.denied(host: host, actor: "system-dismissed")
-            case .timedOut:
-                throw JobNetworkPreflightError.denied(host: host, actor: "system-timeout")
-            }
-        }
-
     }
 
-    private static func loadEnabledSuffixes(repository: DBRepository) async throws -> [String] {
-        let rows = try await repository.loadEgressAllowedDomainSuffixes(includeDisabled: false)
-        return rows.filter(\.enabled).map(\.suffix)
+    private static func blacklistArgumentsJSON(
+        host: String,
+        entry: BlacklistEntry,
+        toolName: String
+    ) -> String {
+        let payload: [String: String] = [
+            "host": host,
+            "url": "https://\(host)",
+            "toolName": toolName,
+            "kind": "blacklist",
+            "pattern": entry.displayPattern,
+        ]
+        guard let data = try? JSONSerialization.data(withJSONObject: payload),
+              let json = String(data: data, encoding: .utf8) else {
+            return #"{"host":"\#(host)","toolName":"\#(toolName)","kind":"blacklist","pattern":"\#(entry.displayPattern)"}"#
+        }
+        return json
     }
 }
diff --git a/ui/SharedAgentRuntime/LLMProviderCredentialGate.swift b/ui/SharedAgentRuntime/LLMProviderCredentialGate.swift
index 4dfecd82..58cb31df 100644
--- a/ui/SharedAgentRuntime/LLMProviderCredentialGate.swift
+++ b/ui/SharedAgentRuntime/LLMProviderCredentialGate.swift
@@ -1,14 +1,40 @@
 import Foundation
 import Structure
 
-/// Whether an LLM provider has a usable API key (Keychain or `.env`, per `AppSecretResolver`).
+/// Provider credential checks and API key resolution (Keychain or `.env`, per `AppSecretResolver`).
 @MainActor
 enum LLMProviderCredentialGate {
-    static func hasAPIKey(for provider: LLMProviderChoice, resolver: AppSecretResolver) -> Bool {
+    /// One key per provider — the single resolution path for chat, reviewers, workers, and jobs.
+    static func resolveAPIKey(
+        for provider: LLMProviderChoice,
+        resolver: AppSecretResolver = AppSecretResolver()
+    ) -> String? {
         resolver.resolve(
             account: provider.secretAccount,
             environmentKeys: provider.apiKeyEnvironmentKeys
-        ) != nil
+        )
+    }
+
+    static func resolveAPIKey(
+        for model: LLMModelChoice,
+        resolver: AppSecretResolver = AppSecretResolver()
+    ) -> String? {
+        resolveAPIKey(for: model.provider, resolver: resolver)
+    }
+
+    /// Off-main callers (AgentService, MCPService, jobs).
+    static func resolveAPIKey(for provider: LLMProviderChoice) async -> String? {
+        await MainActor.run {
+            resolveAPIKey(for: provider)
+        }
+    }
+
+    static func resolveAPIKey(for model: LLMModelChoice) async -> String? {
+        await resolveAPIKey(for: model.provider)
+    }
+
+    static func hasAPIKey(for provider: LLMProviderChoice, resolver: AppSecretResolver) -> Bool {
+        resolveAPIKey(for: provider, resolver: resolver) != nil
     }
 
     static func configuredProviders(resolver: AppSecretResolver) -> [LLMProviderChoice] {
diff --git a/ui/SharedAgentRuntime/Resources/conversation_rag_instructions.md b/ui/SharedAgentRuntime/Resources/conversation_rag_instructions.md
index 1c488a09..7b381d60 100644
--- a/ui/SharedAgentRuntime/Resources/conversation_rag_instructions.md
+++ b/ui/SharedAgentRuntime/Resources/conversation_rag_instructions.md
@@ -13,18 +13,11 @@ Use a tool when the user asks for any of:
 - search, look up, browse, fetch, scrape, or “from the web / online”
 - site-specific retail or catalog data (e.g. Amazon, “best sellers”, “top 10 … being sold”, prices, availability)
 
-Use `script_exec` for scripting, automation, and live web access through the host HTTP bridge.
-
 For those requests:
 1. Prefer calling the tool **on the first turn** with reasonable defaults.
 2. Do **not** answer with only clarifying questions when a sensible default exists (e.g. US site, general category, bestseller or top search results). State the default you used in the final answer after the tool runs.
 3. Ask a clarifying question only when the request is impossible to execute without a critical missing fact (not for optional polish).
 4. Never invent live rankings, prices, stock, market moves, or “what’s selling now” from training data.
-5. For current events / market turmoil: fetch real articles from news or finance sites (not Google search results pages). If a scrape returns no usable content, retry with other sites before concluding data is unavailable.
-
-## Response format
-
-Always respond using the required JSON schema (`thinking` / `tool_call` / `tool_batch` / `complete`). Never reply as free-form plain text outside that schema.
 
 When presenting a list of choices, options, steps, items, or alternative paths to the user, ALWAYS format them as a clean Markdown bulleted list (using `-` or `*`) or a numbered list (using `1.`, `2.`), instead of writing them as plain paragraphs.
 
diff --git a/ui/SharedAgentRuntime/Resources/mcp_tool_instructions.md b/ui/SharedAgentRuntime/Resources/mcp_tool_instructions.md
index 8e015391..11753240 100644
--- a/ui/SharedAgentRuntime/Resources/mcp_tool_instructions.md
+++ b/ui/SharedAgentRuntime/Resources/mcp_tool_instructions.md
@@ -7,31 +7,11 @@
    - Set `status` to "tool_call" when you need to execute a single tool, and populate the `tool_call` object with your target `tool_name` and a stringified, JSON-formatted string of tool arguments under the `arguments` key.
    - Set `status` to "tool_batch" when you need to execute multiple tools in parallel, and populate the `tool_batch` object with your list of `invocations`.
    - Set `status` to "complete" when you have finished and are responding directly to the user, and populate the `assistant_response` field with your Markdown reply.
-   - Pass tool `arguments` as a **stringified JSON object** under the `arguments` key (schema requirement). Prefer short Python source and avoid embedding unescaped double quotes in the script body.
+   - Pass tool `arguments` as a **stringified JSON object** under the `arguments` key (schema requirement). Prefer short Go source and avoid embedding unescaped double quotes in the script body.
 6. Users should not have to name tools. Choose tools autonomously from intent.
-7. Use `files.extract` for attached PDFs, Office documents, HTML, CSV, and Excel. Use `script_exec` for other scripting/automation. Use `web.crawl` for live website access.
-   1. For `script_exec`, use standalone **Python** only. Read one JSON event from standard input and write a JSON **array** of envelopes to standard output. Do not use sockets, urllib/requests, subprocess, shell commands, credentials, or package dependencies.
-   2. The container has no network. Emit `http.request` envelopes; the host performs HTTP and invokes the guest program again with an `http_results` event.
-   3. On the first hop emit `{"verb":"http.request","request_id":"…","method":"GET","url":"…"}`. On `http_results`, parse the supplied UTF-8 body and emit `result.emit` or `message.post`.
-   4. The script must complete the user's requested extraction or summary, not only prove that a fetch happened. Never emit `repr(http_results)` or copy an entire fetched body into `content` unless the user explicitly requested the raw source. For HTML/XML, remove scripts and styles, extract the relevant visible fields, normalize the text, and cap the result. If raw HTML is explicitly requested, emit it in `html`; the host sanitizes that field.
-   5. Prefer content sites. Do **not** scrape Google/Bing/Yahoo SERP HTML.
-   6. Keep scripts short. Use `timeout_seconds` on the tool args if needed.
-   7. If the first fetch is empty, try another `script_exec` with different URLs before answering.
-   8. If `script_exec` returns `blocked` or `failed` with implementation findings, treat those
-      findings as correction feedback and make at most one corrected `script_exec` call before
-      answering. Do not repeat the same script unchanged. If the reviewer identifies a security
-      refusal or the corrected call also fails, report the exact finding instead of claiming success.
-9. Use `web.crawl` for website crawling instead of generating a crawler script. Because a crawl
-   can run for a long time, submit it through `jobs_create` with `tool_name` set to `web.crawl`,
-   `wake_after` set to true, and a short `wake_prompt` that tells the agent to present the crawl
-   result to the user. The immediate response must say the crawl was submitted and that the
-   result will arrive in a notification banner. Never request more than 900 seconds.
-10. A web crawl goal must describe the requested result. Never use it for DDoS, flooding,
-    load/stress testing, port scanning, brute force, or other high-volume behavior. Keep the
-    crawl same-origin and rely on the tool's page, depth, byte, rate, and timeout limits.
-11. Use `files.extract` for attached files instead of generating an extractor script. Call it directly; do not submit it through `jobs_create`. Omit `filenames` to process every attached file in this chat. Never request more than 180 seconds.
-12. After tool execution, respond with clean user-facing output only (Markdown/JSON/CSV as requested); do not include raw tool-call JSON, escaped script source, or internal control payloads.
-13. Multi-agent tools (when listed in the catalog):
+7. Use `files.extract` for attached files, `script_exec` for other scripting/automation, and `web.crawl` for live website access. Obey the bundled guest SDK (`script-exec-contract.json`) for `script_exec`; obey the web crawler and file extractor skills for those tools.
+8. After tool execution, respond with clean user-facing output only (Markdown/JSON/CSV as requested); do not include raw tool-call JSON, escaped script source, or internal control payloads.
+9. Multi-agent tools (when listed in the catalog):
    1. If the user names a multi-agent tool or asks to spawn/list/send/cancel agents, issue that `tool_call` (or `tool_batch`) **before** any `complete` answer. Do not invent tool results.
    2. `agents_spawn` — required args: `goal` (short), `task` (concrete). Blocks until the worker finishes; use the returned `result` in your next step. Optional `agent_id` slug.
    3. Workers never talk to the user; you synthesize worker results into the final `assistant_response`.
diff --git a/ui/SharedAgentRuntime/Resources/script_reviewer_instructions.md b/ui/SharedAgentRuntime/Resources/script_reviewer_instructions.md
deleted file mode 100644
index 1c7b9c8e..00000000
--- a/ui/SharedAgentRuntime/Resources/script_reviewer_instructions.md
+++ /dev/null
@@ -1,37 +0,0 @@
-You are a reviewer for script_exec declarations.
-
-FAIL-FAST (mandatory):
-- Apply checks in order. As soon as ANY single check fails, return with failure JSON immediately.
-- Do NOT continue scanning for more issues after the first failure.
-- On first failure: return suggestedAction "deny", alignedWithRequest false, concerns with only that one failing reason, and a short summary. No essays.
-- Only if every check passes: return suggestedAction "allow" with a brief summary (1-2 sentences). concerns may be empty or at most one minor operational note.
-
-Checks (if any fail return failure JSON immediately):
-1) Script, description, reason, and user prompt are consistent (intent alignment).
-   Derrick has a job scheduler (jobs_create / run_after_seconds / cron). Timing is applied by
-   JobService before this script runs. The script must do the work immediately when invoked.
-   Words like delayed, scheduled, in 7 seconds, later, or run_after in the reason or user_prompt
-   refer to that scheduler — not to sleep/setTimeout inside the script. Do not deny a script
-   that performs the requested work (e.g. netFetch the URL) just because it has no delay.
-2) No tokens, API keys, passwords, or other secret literals in the source.
-
-3) The script implements the requested terminal result, not just the fetch.
-   For requests to summarize, list, inspect, or extract fetched content, the `http_results` branch
-   must parse the relevant response body and emit the requested data. Do not allow
-   `repr(http_results)`, a fetch-only confirmation, or an entire raw body copied to
-   `content` unless the user explicitly requested the raw source. If raw HTML is requested, `html`
-   is allowed because the host sanitizes it before rendering.
-4) Fetched HTML/XML is treated as untrusted data. Text and Markdown results must remove unsafe
-   markup and validate generated links as http or https. Do not reject ordinary safe HTML in the
-   `html` field solely because the host performs the final sanitization.
-
-Do not deny for Python style, envelope construction, destination URLs, or the absence of dependencies. The static Python verifier enforces direct network and process restrictions. The guest has no network; the host performs HTTP and applies SSRF there.
-
-Return only valid JSON with this exact schema:
-{
-  "alignedWithRequest": true|false,
-  "confidence": 0.0-1.0,
-  "suggestedAction": "allow"|"deny",
-  "concerns": ["..."],
-  "summary": "short explanation"
-}
diff --git a/ui/SharedAgentRuntime/Resources/web_crawler_skill.md b/ui/SharedAgentRuntime/Resources/web_crawler_skill.md
index f9d7be7e..4dc1eb69 100644
--- a/ui/SharedAgentRuntime/Resources/web_crawler_skill.md
+++ b/ui/SharedAgentRuntime/Resources/web_crawler_skill.md
@@ -3,8 +3,10 @@
 Use the `web.crawl` MCP tool for website crawling. Do not generate a crawler
 script with `script_exec`.
 
-Submit every crawl through `jobs_create` so the user receives the result in a
-notification banner.
+Call `web.crawl` directly in live chat for typical crawls. Submit through
+`jobs_create` only when the crawl is likely to take more than about one minute
+(large page budget, deep site, or long timeout). Background crawls should use
+`wake_after: true` so the user gets a notification banner when they finish.
 
 Required `web.crawl` arguments:
 
diff --git a/ui/SharedAgentRuntime/Services/DaemonProcessHygiene.swift b/ui/SharedAgentRuntime/Services/DaemonProcessHygiene.swift
index 4b60200c..fd909ce4 100644
--- a/ui/SharedAgentRuntime/Services/DaemonProcessHygiene.swift
+++ b/ui/SharedAgentRuntime/Services/DaemonProcessHygiene.swift
@@ -22,7 +22,7 @@ public enum DaemonProcessHygiene {
             reportedFingerprint: health.executableFingerprint,
             expectedFingerprint: expectedFingerprint(),
             reportedGuestRuntime: health.guestRuntimeImage,
-            expectedGuestRuntime: DerrickGuestRuntime.pythonGuestDockerImage
+            expectedGuestRuntime: DerrickGuestRuntime.guestDockerImage
         )
     }
 
diff --git a/ui/SharedAgentRuntime/Services/XPCConversationToolClient.swift b/ui/SharedAgentRuntime/Services/XPCConversationToolClient.swift
index e02829a9..dd097866 100644
--- a/ui/SharedAgentRuntime/Services/XPCConversationToolClient.swift
+++ b/ui/SharedAgentRuntime/Services/XPCConversationToolClient.swift
@@ -9,19 +9,16 @@ import Structure
 public struct XPCConversationToolClient: ConversationToolClient, Sendable {
     private let principal: ServicePrincipal
     private let agentsClient: MCPClient?
-    private let helperAPIKeyProvider: @Sendable () -> String?
     /// JSON `HelperModelWire` for MCP script security reviewer (from `LLMModelSettings`).
     private let helperReviewerModelJSONProvider: @Sendable () async -> String?
 
     public init(
         principal: ServicePrincipal,
         agentsClient: MCPClient? = nil,
-        helperAPIKeyProvider: @escaping @Sendable () -> String? = { TurnProcessContext.effectiveAPIKey },
         helperReviewerModelJSONProvider: @escaping @Sendable () async -> String? = { nil }
     ) {
         self.principal = principal
         self.agentsClient = agentsClient
-        self.helperAPIKeyProvider = helperAPIKeyProvider
         self.helperReviewerModelJSONProvider = helperReviewerModelJSONProvider
     }
 
@@ -85,7 +82,7 @@ public struct XPCConversationToolClient: ConversationToolClient, Sendable {
             principal: activePrincipal,
             toolName: name,
             argumentsJSON: argumentsJSON,
-            helperAPIKey: helperAPIKeyProvider(),
+            helperAPIKey: nil,
             helperReviewerModelJSON: reviewerModelJSON,
             pluginFactoryCreationActive: executionContextJSON != nil
                 && TurnProcessContext.effectivePluginFactoryCreationActive,
diff --git a/ui/SharedAgentRuntime/Support/AppBootstrapStatus.swift b/ui/SharedAgentRuntime/Support/AppBootstrapStatus.swift
index 543dcda0..e5016dab 100644
--- a/ui/SharedAgentRuntime/Support/AppBootstrapStatus.swift
+++ b/ui/SharedAgentRuntime/Support/AppBootstrapStatus.swift
@@ -18,8 +18,44 @@ final class AppBootstrapStatus: ObservableObject {
         case failed
     }
 
+    /// Parallel bootstrap steps shown in the init modal. Completed steps are removed from the list.
+    enum TaskID: String, Sendable, CaseIterable, Equatable {
+        case daemon
+        case database
+        case docker
+        case workerImage
+
+        var sortOrder: Int {
+            switch self {
+            case .daemon: return 0
+            case .database: return 1
+            case .docker: return 2
+            case .workerImage: return 3
+            }
+        }
+
+        var defaultMessage: String {
+            switch self {
+            case .daemon:
+                return "Connecting to Derrick daemon…"
+            case .database:
+                return "Opening local database…"
+            case .docker:
+                return "Checking Docker Desktop…"
+            case .workerImage:
+                return "Preparing worker image…"
+            }
+        }
+    }
+
+    struct LoadingTask: Identifiable, Equatable, Sendable {
+        let id: TaskID
+        var message: String
+    }
+
     @Published private(set) var phase: Phase = .idle
     @Published private(set) var statusMessage: String = "Starting…"
+    @Published private(set) var activeLoadingTasks: [LoadingTask] = []
     @Published private(set) var failureTitle: String?
     @Published private(set) var failureMessage: String?
     /// Extra recovery control on the failure modal (for example Open Login Items).
@@ -43,6 +79,7 @@ final class AppBootstrapStatus: ObservableObject {
         deferModalPresentation = false
         phase = .idle
         statusMessage = "Starting…"
+        activeLoadingTasks = []
         failureTitle = nil
         failureMessage = nil
         failureRecovery = .none
@@ -108,6 +145,7 @@ final class AppBootstrapStatus: ObservableObject {
         deferModalPresentation = deferModal
         phase = .loadingSession
         statusMessage = "Loading session store…"
+        activeLoadingTasks = []
         failureTitle = nil
         failureMessage = nil
         failureRecovery = .none
@@ -138,38 +176,86 @@ final class AppBootstrapStatus: ObservableObject {
         }
     }
 
+    func beginTask(_ id: TaskID, message: String? = nil) {
+        guard isInitializing else { return }
+        let label = message ?? id.defaultMessage
+        if let index = activeLoadingTasks.firstIndex(where: { $0.id == id }) {
+            activeLoadingTasks[index].message = label
+        } else {
+            activeLoadingTasks.append(LoadingTask(id: id, message: label))
+            activeLoadingTasks.sort { $0.id.sortOrder < $1.id.sortOrder }
+        }
+        if !deferModalPresentation {
+            isModalPresented = true
+        }
+        debugLog("[bootstrap] task begin \(id.rawValue): \(label)")
+    }
+
+    func updateTask(_ id: TaskID, message: String) {
+        guard isInitializing else { return }
+        if let index = activeLoadingTasks.firstIndex(where: { $0.id == id }) {
+            activeLoadingTasks[index].message = message
+        } else {
+            beginTask(id, message: message)
+        }
+        debugLog("[bootstrap] task update \(id.rawValue): \(message)")
+    }
+
+    func completeTask(_ id: TaskID) {
+        guard activeLoadingTasks.contains(where: { $0.id == id }) else { return }
+        activeLoadingTasks.removeAll { $0.id == id }
+        debugLog("[bootstrap] task complete \(id.rawValue)")
+    }
+
     func update(phase: Phase, message: String) {
         // Never re-open the modal after ready (parallel service ensure-up must not reflash it).
         if self.phase == .ready, phase != .failed, phase != .ready {
             debugLog("[bootstrap] ignore phase=\(phase.rawValue) (already ready): \(message)")
             return
         }
-        // Parallel bootstrap: once we move past Docker prep, do not let guest-image
-        // prewarm overwrite daemon/database status in the modal.
-        if phase == .checkingDocker || phase == .preparingImage || phase == .verifyingEnvironment {
-            switch self.phase {
-            case .connectingHelper, .loadingSession:
-                debugLog("[bootstrap] ignore docker phase=\(phase.rawValue) while \(self.phase.rawValue): \(message)")
-                return
-            default:
-                break
-            }
+        // Parallel bootstrap: keep the highest-priority in-flight step visible (daemon connect
+        // beats "Opening local database…" while XPC is still retrying).
+        if isInitializing, Self.phasePriority(phase) < Self.phasePriority(self.phase) {
+            debugLog("[bootstrap] ignore lower-priority phase=\(phase.rawValue) while \(self.phase.rawValue): \(message)")
+        } else {
+            // Don't let a cancelled re-entrant task demote ready via failed paths above.
+            self.phase = phase
+            self.statusMessage = message
         }
-        // Don't let a cancelled re-entrant task demote ready via failed paths above.
-        self.phase = phase
-        self.statusMessage = message
+        syncLoadingTask(for: phase, message: message)
         if !deferModalPresentation {
             isModalPresented = true
         }
         debugLog("[bootstrap] phase=\(phase.rawValue) \(message)")
     }
 
+    private func syncLoadingTask(for phase: Phase, message: String) {
+        guard isInitializing else { return }
+        switch phase {
+        case .connectingHelper:
+            beginTask(.daemon, message: message)
+        case .loadingSession:
+            if message.localizedCaseInsensitiveContains("database") {
+                beginTask(.database, message: message)
+            }
+        case .checkingDocker:
+            beginTask(.docker, message: message)
+        case .preparingImage:
+            beginTask(.workerImage, message: message)
+        case .verifyingEnvironment:
+            completeTask(.workerImage)
+        default:
+            break
+        }
+    }
+
     func markReady() {
         deferredModalRevealTask?.cancel()
         deferredModalRevealTask = nil
         deferModalPresentation = false
         phase = .ready
         statusMessage = "Ready"
+        activeLoadingTasks = []
         failureTitle = nil
         failureMessage = nil
         failureRecovery = .none
@@ -213,6 +299,7 @@ final class AppBootstrapStatus: ObservableObject {
         deferModalPresentation = false
         phase = .idle
         statusMessage = "Starting…"
+        activeLoadingTasks = []
         failureTitle = nil
         failureMessage = nil
         failureRecovery = .none
@@ -226,6 +313,16 @@ final class AppBootstrapStatus: ObservableObject {
         debugLog("[bootstrap] failure modal dismissed")
     }
 
+    private static func phasePriority(_ phase: Phase) -> Int {
+        switch phase {
+        case .connectingHelper: return 4
+        case .checkingDocker: return 3
+        case .preparingImage, .verifyingEnvironment: return 2
+        case .loadingSession: return 1
+        default: return 0
+        }
+    }
+
     enum FailureRecovery: Equatable, Sendable {
         case none
         case retryDaemon
@@ -240,6 +337,9 @@ final class AppBootstrapStatus: ObservableObject {
 
     /// Maps prewarm / Docker errors into a short title and user-facing explanation.
     static func classifyError(_ error: Error) -> ClassifiedFailure {
+        if let goError = error as? DerrickGoToolchainError {
+            return classifyGoToolchainError(goError)
+        }
         if let agentError = error as? JobServiceLoginAgent.AgentError {
             return classifyDaemonAgentError(agentError)
         }
@@ -338,6 +438,40 @@ final class AppBootstrapStatus: ObservableObject {
         )
     }
 
+    private static func classifyGoToolchainError(
+        _ error: DerrickGoToolchainError
+    ) -> ClassifiedFailure {
+        switch error {
+        case .missing:
+            return ClassifiedFailure(
+                title: "Go Toolchain Required",
+                message: """
+                Derrick could not find a Go toolchain for development diagnostics. Guest compile runs in Docker; this error is unexpected.
+
+                Quit and reopen Derrick. If it persists, reinstall Docker Desktop.
+                """
+            )
+        case .unparseable:
+            return ClassifiedFailure(
+                title: "Go Toolchain Unreadable",
+                message: """
+                Derrick could not read the installed Go version. Guest compile runs in Docker; this error is unexpected.
+
+                \(error.localizedDescription)
+                """
+            )
+        case .tooOld(_, let required):
+            return ClassifiedFailure(
+                title: "Go Toolchain Too Old",
+                message: """
+                Derrick found an older Go toolchain than \(required). Guest compile runs in Docker; this error is unexpected.
+
+                Quit and reopen Derrick.
+                """
+            )
+        }
+    }
+
     private static func classifyDaemonAgentError(
         _ error: JobServiceLoginAgent.AgentError
     ) -> ClassifiedFailure {
diff --git a/ui/SharedAgentRuntime/Support/DockerRunner/XPCDockerRunner.swift b/ui/SharedAgentRuntime/Support/DockerRunner/XPCDockerRunner.swift
index f667eef2..b08dedf1 100644
--- a/ui/SharedAgentRuntime/Support/DockerRunner/XPCDockerRunner.swift
+++ b/ui/SharedAgentRuntime/Support/DockerRunner/XPCDockerRunner.swift
@@ -164,11 +164,13 @@ public final class XPCDockerRunner: @unchecked Sendable {
     public static let shared = XPCDockerRunner()
 
     private static let serviceName = "derrick.ui.DockerRunnerHelper"
-    private static let prewarmWaitCeilingSeconds: UInt64 = 1_200
+    private static let dockerReachableWaitCeilingSeconds: UInt64 = 60
+    private static let imagePrewarmWaitCeilingSeconds: UInt64 = 1_200
 
     private let connection: NSXPCConnection
     private let appLogSink: XPCAppLogSink
-    private let prewarmState = PrewarmState()
+    private let dockerReachableState = PrewarmState()
+    private let imagePrewarmState = PrewarmState()
 
     public init() {
         let sink = XPCAppLogSink()
@@ -206,11 +208,35 @@ public final class XPCDockerRunner: @unchecked Sendable {
         }
     }
 
+    /// Waits until Docker Desktop responds. Does not wait for the worker image build.
+    public func waitUntilDockerReachable() async throws {
+        if dockerReachableState.isCompleted() {
+            return
+        }
+        if let failure = dockerReachableState.failureIfCompleted() {
+            throw failure
+        }
+        let timeout = NSError(
+            domain: "XPCDockerRunner",
+            code: 504,
+            userInfo: [
+                NSLocalizedDescriptionKey:
+                    "Docker Desktop did not respond within \(Self.dockerReachableWaitCeilingSeconds)s."
+            ]
+        )
+        try await dockerReachableState.wait(
+            timeoutNanoseconds: Self.dockerReachableWaitCeilingSeconds * 1_000_000_000,
+            timeoutError: timeout
+        )
+    }
+
+    /// Waits until the worker image is built or verified. Joins an in-flight background build.
     public func waitUntilPrewarmed() async throws {
-        if prewarmState.isCompleted() {
+        try await waitUntilDockerReachable()
+        if imagePrewarmState.isCompleted() {
             return
         }
-        if let failure = prewarmState.failureIfCompleted() {
+        if let failure = imagePrewarmState.failureIfCompleted() {
             throw failure
         }
         let timeout = NSError(
@@ -218,11 +244,11 @@ public final class XPCDockerRunner: @unchecked Sendable {
             code: 504,
             userInfo: [
                 NSLocalizedDescriptionKey:
-                    "Guest runtime setup timed out after \(Self.prewarmWaitCeilingSeconds)s."
+                    "Worker image setup timed out after \(Self.imagePrewarmWaitCeilingSeconds)s."
             ]
         )
-        try await prewarmState.wait(
-            timeoutNanoseconds: Self.prewarmWaitCeilingSeconds * 1_000_000_000,
+        try await imagePrewarmState.wait(
+            timeoutNanoseconds: Self.imagePrewarmWaitCeilingSeconds * 1_000_000_000,
             timeoutError: timeout
         )
     }
@@ -280,21 +306,28 @@ public final class XPCDockerRunner: @unchecked Sendable {
                     ]
                 )
             }
-            await reportBootstrap(phase: .preparingImage, message: "Preparing guest runtime…")
-            let executor = makeDockerExecutor()
-            let image = DerrickGuestRuntime.pythonGuestDockerImage
-            let inspect = try await executor(["image", "inspect", image], Data(), 30)
-            if inspect.exitCode != 0 {
-                await MainActor.run {
-                    AppBootstrapStatus.shared.revealModalIfStillInitializing()
-                }
-                try await OneshotDockerContainer.ensurePulledImage(image, executor: executor)
+            dockerReachableState.markCompleted()
+            await reportBootstrapTaskCompleted(.docker)
+            Task {
+                await prewarmWorkerImage()
             }
-            prewarmState.markCompleted()
-            await reportBootstrap(phase: .verifyingEnvironment, message: "Guest runtime ready.")
         } catch {
-            debugLog("Guest runtime prewarming failed: \(error.localizedDescription)")
-            prewarmState.markFailed(error)
+            debugLog("Docker reachability check failed: \(error.localizedDescription)")
+            dockerReachableState.markFailed(error)
+            imagePrewarmState.markFailed(error)
+        }
+    }
+
+    private func prewarmWorkerImage() async {
+        do {
+            await reportBootstrap(phase: .preparingImage, message: "Preparing worker image…")
+            let executor = makeDockerExecutor()
+            try await WorkerImageGate.shared.ensureReady(executor: executor)
+            imagePrewarmState.markCompleted()
+            await reportBootstrap(phase: .verifyingEnvironment, message: "Worker image ready.")
+        } catch {
+            debugLog("Worker image prewarm failed: \(error.localizedDescription)")
+            imagePrewarmState.markFailed(error)
         }
     }
 
@@ -381,6 +414,14 @@ public final class XPCDockerRunner: @unchecked Sendable {
         }
     }
 
+    private func reportBootstrapTaskCompleted(_ id: AppBootstrapStatus.TaskID) async {
+        await MainActor.run {
+            let status = AppBootstrapStatus.shared
+            guard status.isInitializing else { return }
+            status.completeTask(id)
+        }
+    }
+
     deinit {
         connection.invalidate()
     }
diff --git a/ui/SharedAgentRuntime/Support/Egress/EgressAllowlistService.swift b/ui/SharedAgentRuntime/Support/Egress/EgressAllowlistService.swift
deleted file mode 100644
index 03c3ef13..00000000
--- a/ui/SharedAgentRuntime/Support/Egress/EgressAllowlistService.swift
+++ /dev/null
@@ -1,273 +0,0 @@
-import Foundation
-import Combine
-import DBRepository
-import EgressProxy
-import AppEvents
-import PolicyUserInteraction
-import Structure
-
-/// App-owned egress allowlist: DB persistence + host HTTP preflight prompts.
-/// Not exposed as MCP. Not part of tool/content policy rules.
-@MainActor
-final class EgressAllowlistService: ObservableObject {
-    static let shared = EgressAllowlistService()
-
-    @Published private(set) var suffixes: [EgressAllowedDomainSuffix] = []
-
-    private var repository: DBRepository?
-    private let username = "ui"
-    private let password = "ui"
-    private let localPolicy = DefaultDestinationPolicy(allowedDomainSuffixes: [])
-
-    private init() {}
-
-    func configure(repository: DBRepository) async {
-        self.repository = repository
-        do {
-            let inserted = try await repository.seedEgressAllowedDomainSuffixesIfNeeded(
-                EgressProxyConfiguration.defaultSeedDomainSuffixes,
-                source: "seed"
-            )
-            if inserted > 0 {
-                debugLog("Egress allowlist seed inserted \(inserted) suffix(es).")
-            } else {
-                debugLog("Egress allowlist seed skipped (suffixes already present).")
-            }
-            try await reload()
-        } catch {
-            debugLog("Egress allowlist configure failed: \(error.localizedDescription)")
-        }
-    }
-
-    func reload(clearSessionHosts: Bool = false) async throws {
-        guard let repository else {
-            suffixes = []
-            return
-        }
-        let rows = try await repository.loadEgressAllowedDomainSuffixes(includeDisabled: true)
-        suffixes = rows
-        localPolicy.setAllowedDomainSuffixes(rows.filter(\.enabled).map(\.suffix))
-        if clearSessionHosts {
-            // Settings edits must not be shadowed by prior Allow-once / mid-flight grants.
-            localPolicy.clearSessionHosts()
-        }
-    }
-
-    private var isAgentServiceProcess: Bool {
-        let bid = Bundle.main.bundleIdentifier ?? ""
-        return bid == DerrickServiceID.agent.rawValue || bid.hasSuffix(".AgentService")
-    }
-
-    func addSuffix(_ raw: String, source: String = "user") async throws {
-        let suffix = EgressHostExtractor.permanentSuffix(for: raw)
-        guard EgressHostExtractor.isPlausibleHostname(suffix) || suffix.contains(".") else {
-            throw NSError(
-                domain: "EgressAllowlist",
-                code: 1,
-                userInfo: [NSLocalizedDescriptionKey: "Invalid domain suffix: \(raw)"]
-            )
-        }
-        guard let repository else { return }
-        try await repository.saveEgressAllowedDomainSuffix(
-            EgressAllowedDomainSuffix(suffix: suffix, source: source, enabled: true)
-        )
-        try await reload()
-    }
-
-    func removeSuffix(id: String) async throws {
-        guard let repository else { return }
-        try await repository.deleteEgressAllowedDomainSuffix(id: id)
-        try await reload(clearSessionHosts: true)
-        debugLog("Egress allowlist removed id=\(id)")
-    }
-
-    /// Preflight network hosts before script execution.
-    /// - Returns: nil if allowed to proceed; blocked tool-result JSON if user denied or hard-blocked.
-    func preflightScriptNetwork(
-        script: String,
-        allowNetwork: Bool,
-        toolName: String = "script_exec"
-    ) async -> String? {
-        guard allowNetwork else { return nil }
-
-        let preflightStarted = Date()
-        let hosts = EgressHostExtractor.extractHosts(from: script)
-        guard !hosts.isEmpty else {
-            PipelineTiming.log("egress_preflight hosts=0 total_ms=0 modal_ms=0")
-            return nil
-        }
-
-        var sessionGrants: [String] = []
-        var modalMS = 0
-        var needsPrompt: [String] = []
-
-        for host in hosts {
-            if localPolicy.isHardBlockedHostname(host) {
-                let message = "Network access to “\(host)” is permanently blocked (private/metadata host)."
-                PipelineTiming.log(
-                    "egress_preflight blocked_hard host=\(host) total_ms=\(PipelineTiming.elapsedMS(from: preflightStarted)) modal_ms=\(modalMS)"
-                )
-                // Modal is published by the pipeline from the common network outcome.
-                return Self.blockedResultJSON(findings: [message])
-            }
-
-            if localPolicy.isHostCoveredByAllowlist(host) {
-                continue
-            }
-            needsPrompt.append(host)
-        }
-
-        if !needsPrompt.isEmpty {
-            let modalStarted = Date()
-            let decision = await promptForHosts(needsPrompt, toolName: toolName)
-            modalMS += PipelineTiming.elapsedMS(from: modalStarted)
-            switch decision {
-            case .approved(let actor), .approvedOnce(let actor):
-                debugLog("Egress allow once for \(needsPrompt.count) host(s) by \(actor ?? "user")")
-                sessionGrants.append(contentsOf: needsPrompt)
-                localPolicy.grantSessionHosts(needsPrompt)
-            case .approvedPermanently(let actor):
-                debugLog("Egress allow always for \(needsPrompt.count) host(s) by \(actor ?? "user")")
-                for host in needsPrompt {
-                    let suffix = EgressHostExtractor.permanentSuffix(for: host)
-                    do {
-                        try await addSuffix(suffix, source: "user")
-                        sessionGrants.append(host)
-                        localPolicy.grantSessionHosts([host])
-                    } catch {
-                        debugLog("Failed to persist egress suffix \(suffix): \(error.localizedDescription)")
-                        PipelineTiming.log(
-                            "egress_preflight persist_failed host=\(host) total_ms=\(PipelineTiming.elapsedMS(from: preflightStarted)) modal_ms=\(modalMS)"
-                        )
-                        return Self.blockedResultJSON(
-                            findings: ["Failed to save permanent allow for \(host): \(error.localizedDescription)"]
-                        )
-                    }
-                }
-            case .denied(let actor):
-                debugLog("Egress deny for \(needsPrompt.count) host(s) by \(actor ?? "user") — aborting entire script run")
-                let listed = needsPrompt.joined(separator: ", ")
-                let message = "User denied network access to “\(listed)”. The script was not run."
-                PipelineTiming.log(
-                    "egress_preflight user_denied hosts=\(needsPrompt.count) total_ms=\(PipelineTiming.elapsedMS(from: preflightStarted)) modal_ms=\(modalMS) prompted_hosts=\(needsPrompt.count)"
-                )
-                return Self.blockedResultJSON(findings: [message])
-            case .dismissed, .timedOut:
-                let listed = needsPrompt.joined(separator: ", ")
-                let message = "Network access to “\(listed)” was not approved. The script was not run."
-                PipelineTiming.log(
-                    "egress_preflight dismissed_or_timeout hosts=\(needsPrompt.count) total_ms=\(PipelineTiming.elapsedMS(from: preflightStarted)) modal_ms=\(modalMS)"
-                )
-                return Self.blockedResultJSON(findings: [message])
-            }
-        }
-
-        PipelineTiming.log(
-            "egress_preflight ok hosts=\(hosts.count) prompted=\(needsPrompt.count) session_grants=\(sessionGrants.count) total_ms=\(PipelineTiming.elapsedMS(from: preflightStarted)) modal_ms=\(modalMS)"
-        )
-        return nil
-    }
-
-    private func promptForHosts(_ hosts: [String], toolName: String) async -> PolicyUserDecision {
-        let unique = Self.uniqueHosts(hosts)
-        guard !unique.isEmpty else {
-            return .denied(actor: "system")
-        }
-
-        if let remote = TurnProcessContext.effectiveNetworkAccessPrompt {
-            var last: PolicyUserDecision = .denied(actor: "system")
-            for host in unique {
-                debugLog("Egress prompt via AgentService path host=\(host)")
-                last = await remote(host, toolName)
-                switch last {
-                case .denied, .dismissed, .timedOut:
-                    return last
-                case .approved, .approvedOnce, .approvedPermanently:
-                    continue
-                }
-            }
-            return last
-        }
-
-        if !isAgentServiceProcess {
-            debugLog("Egress prompt via UI modal hosts=\(unique.count)")
-            let event = PolicyUserEventFactory.egressAccessRequest(
-                hosts: unique,
-                toolName: toolName
-            )
-            return await AppEventBus.shared.initDecision(event)
-        }
-
-        guard let repository else {
-            return .denied(actor: "system-no-repository")
-        }
-        var last: PolicyUserDecision = .denied(actor: "system")
-        for host in unique {
-            debugLog("Egress prompt via notification path host=\(host)")
-            last = await HITLOfflineNetworkService.awaitDecision(
-                host: host,
-                toolName: toolName,
-                turnID: "egress-agent",
-                isJobContext: false,
-                repository: repository,
-                timeoutNanoseconds: 300_000_000_000
-            )
-            switch last {
-            case .denied, .dismissed, .timedOut:
-                return last
-            case .approved, .approvedOnce, .approvedPermanently:
-                continue
-            }
-        }
-        return last
-    }
-
-    private static func uniqueHosts(_ hosts: [String]) -> [String] {
-        var seen = Set<String>()
-        var ordered: [String] = []
-        for raw in hosts {
-            let host = raw.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
-            guard !host.isEmpty, seen.insert(host).inserted else { continue }
-            ordered.append(host)
-        }
-        return ordered
-    }
-
-    /// Apply a user egress decision in this process.
-    /// Call when the UI answers a network prompt so later requests do not re-prompt.
-    func applyUserNetworkDecision(host: String, decision: PolicyUserDecision) async {
-        let normalized = host.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
-        guard !normalized.isEmpty else { return }
-
-        switch decision {
-        case .approved(let actor), .approvedOnce(let actor):
-            debugLog("Egress UI apply once host=\(normalized) actor=\(actor ?? "?")")
-            localPolicy.grantSessionHosts([normalized])
-        case .approvedPermanently(let actor):
-            debugLog("Egress UI apply always host=\(normalized) actor=\(actor ?? "?")")
-            let suffix = EgressHostExtractor.permanentSuffix(for: normalized)
-            do {
-                try await addSuffix(suffix, source: "user")
-            } catch {
-                debugLog("Egress UI apply always persist failed: \(error.localizedDescription)")
-            }
-            localPolicy.grantSessionHosts([normalized])
-        case .denied, .dismissed, .timedOut:
-            break
-        }
-    }
-
-    private static func blockedResultJSON(findings: [String]) -> String {
-        let diagnostics = findings.isEmpty
-            ? [ToolExecutionOutcome.Diagnostic(code: "egress_denied", message: "Network access was denied.")]
-            : findings.map {
-                ToolExecutionOutcome.Diagnostic(code: "egress_denied", message: $0)
-            }
-        return (try? ToolExecutionOutcome.failure(
-            status: .blocked,
-            stage: .network,
-            diagnostics: diagnostics,
-            retry: ToolExecutionOutcome.Retry(allowed: false)
-        ).encodedJSON()) ?? #"{"status":"blocked","stage":"network","diagnostics":[]}"#
-    }
-}
diff --git a/ui/SharedAgentRuntime/Support/LLM/ConfigureScriptReviewer.swift b/ui/SharedAgentRuntime/Support/LLM/ConfigureScriptReviewer.swift
index 3b9552b6..035572df 100644
--- a/ui/SharedAgentRuntime/Support/LLM/ConfigureScriptReviewer.swift
+++ b/ui/SharedAgentRuntime/Support/LLM/ConfigureScriptReviewer.swift
@@ -21,7 +21,7 @@ actor ConfiguredScriptReviewer: ScriptReviewer {
 
     func review(_ args: ScriptExecutionArguments) async throws -> ScriptReviewOutcome {
         let selectedModel = await MainActor.run { settings.scriptReviewerModel }
-        guard let apiKey = await resolveAPIKey(for: selectedModel) else {
+        guard let apiKey = await LLMProviderCredentialGate.resolveAPIKey(for: selectedModel) else {
             await MainActor.run {
                 debugLog(
                     "Helper reviewer model \(selectedModel.helperDisplayName) unavailable; trying default helper reviewer."
@@ -83,7 +83,7 @@ actor ConfiguredScriptReviewer: ScriptReviewer {
         if selectedModel == defaultModel {
             return nil
         }
-        guard let apiKey = await resolveAPIKey(for: defaultModel) else {
+        guard let apiKey = await LLMProviderCredentialGate.resolveAPIKey(for: defaultModel) else {
             return nil
         }
 
@@ -111,17 +111,4 @@ actor ConfiguredScriptReviewer: ScriptReviewer {
             return try await reviewer.review(args)
         }
     }
-
-    private func resolveAPIKey(for model: LLMModelChoice) async -> String? {
-        if let key = await MainActor.run(body: {
-            AppSecretResolver().resolve(
-                account: model.provider.secretAccount,
-                environmentKeys: model.provider.apiKeyEnvironmentKeys
-            )
-        }), !key.isEmpty {
-            return key
-        }
-        // AgentService XPC process cannot read the UI keychain; use the turn-supplied key.
-        return TurnProcessContext.effectiveAPIKey
-    }
 }
diff --git a/ui/SharedAgentRuntime/Support/LLM/SummarizerConfig.swift b/ui/SharedAgentRuntime/Support/LLM/SummarizerConfig.swift
index fe516fdb..8697e4d8 100644
--- a/ui/SharedAgentRuntime/Support/LLM/SummarizerConfig.swift
+++ b/ui/SharedAgentRuntime/Support/LLM/SummarizerConfig.swift
@@ -111,15 +111,7 @@ actor ConfiguredMemorySummarizer: MemorySummarizer {
     }
 
     private func resolveAPIKey(for model: LLMModelChoice) async -> String? {
-        if let key = await MainActor.run(body: {
-            AppSecretResolver().resolve(
-                account: model.provider.secretAccount,
-                environmentKeys: model.provider.apiKeyEnvironmentKeys
-            )
-        }), !key.isEmpty {
-            return key
-        }
-        return TurnProcessContext.effectiveAPIKey
+        await LLMProviderCredentialGate.resolveAPIKey(for: model)
     }
 
     private static func makeSummary(text: String, keywords: [String], sourceTokenCount: Int) -> MemorySummary {
diff --git a/ui/SharedAgentRuntime/Support/PluginFactoryModels.swift b/ui/SharedAgentRuntime/Support/PluginFactoryModels.swift
index 30ef4955..225f4294 100644
--- a/ui/SharedAgentRuntime/Support/PluginFactoryModels.swift
+++ b/ui/SharedAgentRuntime/Support/PluginFactoryModels.swift
@@ -13,22 +13,18 @@ actor ConfiguredPluginFactoryService {
     private let thinkingSettings: LLMModelThinkingSettings
     private let executor: any PluginFactoryExecutor
     private let logger: PluginFactoryLogger
-    private let apiKeyProvider: @Sendable () -> String?
-
     init(
         repository: DBRepository,
         settings: LLMModelSettings,
         thinkingSettings: LLMModelThinkingSettings,
         executor: any PluginFactoryExecutor,
-        logger: @escaping PluginFactoryLogger = { _ in },
-        apiKeyProvider: @escaping @Sendable () -> String? = { TurnProcessContext.effectiveAPIKey }
+        logger: @escaping PluginFactoryLogger = { _ in }
     ) {
         self.repository = repository
         self.settings = settings
         self.thinkingSettings = thinkingSettings
         self.executor = executor
         self.logger = logger
-        self.apiKeyProvider = apiKeyProvider
     }
 
     func build(
@@ -43,7 +39,6 @@ actor ConfiguredPluginFactoryService {
                 settings: settings,
                 thinkingSettings: thinkingSettings,
                 existingReleases: existingReleases,
-                apiKeyProvider: apiKeyProvider,
                 logger: logger
             ),
             executor: executor,
@@ -51,7 +46,6 @@ actor ConfiguredPluginFactoryService {
                 inner: ConfiguredPluginSafetyReviewer(
                     settings: settings,
                     thinkingSettings: thinkingSettings,
-                    apiKeyProvider: apiKeyProvider,
                     logger: logger
                 )
             ),
@@ -68,20 +62,17 @@ actor ConfiguredPluginFactoryBuilder: PluginFactoryBuilder {
     private let settings: LLMModelSettings
     private let thinkingSettings: LLMModelThinkingSettings
     private let existingReleases: [PluginFactoryReleaseSummary]
-    private let apiKeyProvider: @Sendable () -> String?
     private let logger: PluginFactoryLogger
 
     init(
         settings: LLMModelSettings,
         thinkingSettings: LLMModelThinkingSettings,
         existingReleases: [PluginFactoryReleaseSummary] = [],
-        apiKeyProvider: @escaping @Sendable () -> String? = { TurnProcessContext.effectiveAPIKey },
         logger: @escaping PluginFactoryLogger = { _ in }
     ) {
         self.settings = settings
         self.thinkingSettings = thinkingSettings
         self.existingReleases = existingReleases
-        self.apiKeyProvider = apiKeyProvider
         self.logger = logger
     }
 
@@ -107,15 +98,7 @@ actor ConfiguredPluginFactoryBuilder: PluginFactoryBuilder {
     }
 
     private func resolveAPIKey(for model: LLMModelChoice) async -> String? {
-        if let key = await MainActor.run(body: {
-            AppSecretResolver().resolve(
-                account: model.provider.secretAccount,
-                environmentKeys: model.provider.apiKeyEnvironmentKeys
-            )
-        }), !key.isEmpty {
-            return key
-        }
-        return apiKeyProvider()
+        await LLMProviderCredentialGate.resolveAPIKey(for: model)
     }
 
     private func stream(
@@ -148,49 +131,8 @@ actor ConfiguredPluginFactoryBuilder: PluginFactoryBuilder {
     private static func builderSystemPrompt(for userGoal: String) -> String {
         """
         You are the Derrick plugin builder. Convert the user's goal into one complete Agent Plugin draft.
-        Return exactly one JSON object with these keys:
-        plugin_id (string), version (string), description (string), python_source (string),
-        test_input_json (string containing valid JSON — a serialized object, not prose),
-        skill_files (array of objects with path and body),
-        secrets (array of objects with id, label, and kind; required for connector plugins),
-        role (string, optional: "connector" or "standard").
-        plugin_id must use lowercase letters, numbers, hyphens, and dots only
-        (for example my-connector). Never use underscores in plugin_id.
-        If the plugin needs a username, password, token, or API key, declare them in secrets.
-        kind must be username, password, token, or api_key. id is a stable Keychain key
-        such as username or bot_token. label is the text shown when the user saves the value.
-        Never put real credentials in python_source.
-        Set role to "connector" when the plugin sends and receives messages with an external
-        messaging service (any chat or mail connector). Omit role or use "standard" otherwise.
-        For role connector, include messaging_ops: an array of implemented ops
-        (send_message, poll_inbox, sync_threads). It must match the user goal scope and test_input_json.
-        The host writes messaging_ops into extensions.app.derrick in plugin.json.
-        The host lists connector plugins under Messaging. Do not guess this from the plugin_id.
-        Do not return manifest_json. The host creates the canonical Agent Plugin manifest,
-        including the exact `$schema` field for Agent Plugin 1.0 and the fixed
-        extensions.app.derrick.entrypoint ./app.derrick/plugin.py.
-        \(DerrickGuestPython.modelContract)
+        \(ScriptExecContractPrompts.pluginFactoryBuilderGuide())
         \(ConnectorContractPrompts.builderGuide(forUserGoal: userGoal))
-        Before returning the draft, self-check the implementation:
-        - Sort every returned collection by an explicit stable key after parsing and de-duplicate it.
-        - Match host responses by the emitted request_id.
-        - Use only the Python standard library (no pip, requests, urllib, socket, or subprocess).
-        - The direct test input must exercise the terminal result path with matching http_results fixtures.
-        If skill_files is not needed, return an empty array. Every skill file path must be exactly
-        skills/<name>/SKILL.md.
-        For messaging connector plugins (role connector) that call a vendor HTTP API:
-        - Declare secrets in the manifest only. Never hard-code credentials.
-        - Parse each http_results body as JSON when the vendor returns JSON.
-        - test_input_json http_results must exercise success paths for every messaging_op in scope.
-        - test_input_json must be a single JSON object serialized as a string (valid JSON.parse input).
-        - test_input_json must not be empty or "{}".
-        - For connector plugins, test_input_json must use a hops array:
-          {"hops":[{"kind":"message_in_room","params":{"messaging_op":"send_message",...}},\
-          {"kind":"http_results","http_results":[{"request_id":"...","status":200,"body":"..."}],\
-          "params":{...}}]}
-          Repeat additional hop pairs for each messaging_op in scope. request_id values in fixtures must \
-          match the http.request envelopes your python_source emits.
-        - Match http_results by request_id and de-duplicate with stable sorting; never depend on response order.
         When vendor documentation is supplied in the user prompt, use it only to fill may_call HTTP details.
         """
     }
@@ -201,7 +143,7 @@ actor ConfiguredPluginFactoryBuilder: PluginFactoryBuilder {
             "plugin_id": AgentSchema(type: .string),
             "version": AgentSchema(type: .string),
             "description": AgentSchema(type: .string),
-            "python_source": AgentSchema(type: .string),
+            "go_source": AgentSchema(type: .string),
             "test_input_json": AgentSchema(type: .string),
             "skill_files": AgentSchema(
                 type: .array,
@@ -233,7 +175,7 @@ actor ConfiguredPluginFactoryBuilder: PluginFactoryBuilder {
             ),
         ],
         required: [
-            "plugin_id", "version", "description", "python_source",
+            "plugin_id", "version", "description", "go_source",
             "test_input_json", "skill_files",
         ]
     )
@@ -248,7 +190,7 @@ actor ConfiguredPluginFactoryBuilder: PluginFactoryBuilder {
                 """
                 The host already assigned plugin_id \(host.pluginID) and these secret ids: \
                 \(host.secrets.map(\.id).joined(separator: ", ")). \
-                Return python_source and test_input_json. Do not pick a different plugin_id or secret ids. \
+                Return go_source and test_input_json. Do not pick a different plugin_id or secret ids. \
                 Use {{secret:\(host.secrets.first?.id ?? "bot_token")}} in HTTP headers.
                 """
             )
@@ -315,18 +257,15 @@ actor ConfiguredPluginFactoryBuilder: PluginFactoryBuilder {
 actor ConfiguredPluginSafetyReviewer: PluginFactoryReviewer {
     private let settings: LLMModelSettings
     private let thinkingSettings: LLMModelThinkingSettings
-    private let apiKeyProvider: @Sendable () -> String?
     private let logger: PluginFactoryLogger
 
     init(
         settings: LLMModelSettings,
         thinkingSettings: LLMModelThinkingSettings,
-        apiKeyProvider: @escaping @Sendable () -> String? = { TurnProcessContext.effectiveAPIKey },
         logger: @escaping PluginFactoryLogger = { _ in }
     ) {
         self.settings = settings
         self.thinkingSettings = thinkingSettings
-        self.apiKeyProvider = apiKeyProvider
         self.logger = logger
     }
 
@@ -354,15 +293,7 @@ actor ConfiguredPluginSafetyReviewer: PluginFactoryReviewer {
     }
 
     private func resolveAPIKey(for model: LLMModelChoice) async -> String? {
-        if let key = await MainActor.run(body: {
-            AppSecretResolver().resolve(
-                account: model.provider.secretAccount,
-                environmentKeys: model.provider.apiKeyEnvironmentKeys
-            )
-        }), !key.isEmpty {
-            return key
-        }
-        return apiKeyProvider()
+        await LLMProviderCredentialGate.resolveAPIKey(for: model)
     }
 
     private func stream(
@@ -394,22 +325,9 @@ actor ConfiguredPluginSafetyReviewer: PluginFactoryReviewer {
 
     private static func reviewerSystemPrompt(for userGoal: String?) -> String {
         """
-    You are Derrick's independent plugin alignment and safety reviewer.
-    Review the user's goal, manifest, test_input_json, exact Python source, and direct test output.
-    Return exactly one JSON object:
-    {"decision":"approved|rejected","summary":"...","findings":[
-      {"severity":"info|warning|blocking","category":"alignment|safety|correctness|privacy|supplyChain","message":"..."}
-    ]}
-    Reject unsafe, misleading, unrelated, non-deterministic, credential-seeking, or policy-bypassing code.
-    Apply these checks from observable evidence:
-    - A deterministic result uses stable sorting and de-duplication and does not depend on response order, current time, randomness, or UUIDs.
-    - Source-derived headline titles may be fragments; only generated explanatory summaries must be complete sentences when the manifest requires prose.
-    - `result.emit.html` is an allowed output format. Derrick sanitizes it with an allowlist before rendering. Reject executable script behavior or a deliberate sanitizer bypass, not ordinary safe HTML tags.
-    - Reject missing source-grounded parsing or claims that the direct test output does not support.
-    - For connector plugins, obey the connector protocol JSON below. If a rule is not in that JSON, do not require it.
+    Review the user's goal, manifest, test_input_json, exact Go source, and direct test output.
+    \(ScriptExecContractPrompts.pluginFactoryReviewerGuide())
     \(ConnectorContractPrompts.reviewerGuide(forUserGoal: userGoal))
-    Compilation success is not approval. Do not rewrite the code or approve a draft that fails these checks.
-    Reject Swift source, socket/urllib/requests usage, or missing stdin reads.
     """
     }
 
@@ -449,7 +367,7 @@ actor ConfiguredPluginSafetyReviewer: PluginFactoryReviewer {
         test_input_json:
         \(String(decoding: draft.testInput, as: UTF8.self))
 
-        Python source:
+        Go source:
         \(draft.guestSource)
 
         Direct test output:
diff --git a/ui/SharedAgentRuntime/TurnProcessContext.swift b/ui/SharedAgentRuntime/TurnProcessContext.swift
index ab0f2532..5e5759c7 100644
--- a/ui/SharedAgentRuntime/TurnProcessContext.swift
+++ b/ui/SharedAgentRuntime/TurnProcessContext.swift
@@ -31,7 +31,7 @@ public enum TurnProcessContext {
     /// Active agent profile handle for the current user-facing turn (orchestrator-only tools).
     @TaskLocal public static var activeProfileHandle: String?
 
-    /// Active `/create-plugin` or `/edit-plugin` factory turn (enables sync `web.crawl`).
+    /// Active `/create-plugin` or `/edit-plugin` factory turn.
     @TaskLocal public static var pluginFactoryCreationActive: Bool = false
 
     public static func install(
diff --git a/ui/ui/Jobs/DerrickNotificationService.swift b/ui/ui/Jobs/DerrickNotificationService.swift
index 74b1c9a2..e0c1d92e 100644
--- a/ui/ui/Jobs/DerrickNotificationService.swift
+++ b/ui/ui/Jobs/DerrickNotificationService.swift
@@ -170,15 +170,6 @@ final class DerrickNotificationService {
             fputs("[HumanDecision] resolve skip id=\(approvalID)\n", stderr)
             return
         }
-        if approved, HITLOfflineNetworkService.isNetworkToolName(row.toolName),
-           let host = HITLOfflineNetworkService.host(fromNetworkToolName: row.toolName) {
-            await EgressAllowlistService.shared.applyUserNetworkDecision(
-                host: host,
-                decision: always
-                    ? .approvedPermanently(actor: actor)
-                    : .approvedOnce(actor: actor)
-            )
-        }
         let status: PendingHITLApprovalStatus = approved ? .approved : .cancelled
         let edited = approved ? row.argumentsJSON : nil
         try? await repository.resolveHITLApproval(
@@ -264,9 +255,6 @@ final class DerrickNotificationService {
                 databaseDirectoryURL: directory
             )
             repository = repo
-            if !JobResultPanelSession.isPanelOnlyLaunch {
-                await EgressAllowlistService.shared.configure(repository: repo)
-            }
             return repo
         } catch {
             fputs("[HumanDecision] ensureRepository failed: \(error.localizedDescription)\n", stderr)
diff --git a/ui/ui/Jobs/HITLLiveApprovalHandlers.swift b/ui/ui/Jobs/HITLLiveApprovalHandlers.swift
index cd52c2b2..8f70c351 100644
--- a/ui/ui/Jobs/HITLLiveApprovalHandlers.swift
+++ b/ui/ui/Jobs/HITLLiveApprovalHandlers.swift
@@ -166,51 +166,11 @@ enum HITLLiveApprovalHandlers {
     }
 
     private static func presentNetworkAccess(_ request: AgentNetworkAccessRequestDTO) async -> AgentNetworkAccessDecisionDTO {
-        let event = PolicyUserEventFactory.egressAccessRequest(
-            host: request.host,
-            toolName: request.toolName,
-            correlationId: request.requestID
+        // Blacklist-only egress: public hosts are allowed by default. Blacklist hits use PolicyEventBus.
+        AgentNetworkAccessDecisionDTO(
+            requestID: request.requestID,
+            decision: "once",
+            actor: "blacklist-only-auto"
         )
-        let decision = await AppEventBus.shared.initDecision(event)
-        switch decision {
-        case .approvedOnce(let actor):
-            await EgressAllowlistService.shared.applyUserNetworkDecision(
-                host: request.host,
-                decision: .approvedOnce(actor: actor)
-            )
-            return AgentNetworkAccessDecisionDTO(
-                requestID: request.requestID,
-                decision: "once",
-                actor: actor ?? "ui-modal-once"
-            )
-        case .approvedPermanently(let actor):
-            await EgressAllowlistService.shared.applyUserNetworkDecision(
-                host: request.host,
-                decision: .approvedPermanently(actor: actor)
-            )
-            return AgentNetworkAccessDecisionDTO(
-                requestID: request.requestID,
-                decision: "always",
-                actor: actor ?? "ui-modal-always"
-            )
-        case .timedOut:
-            return AgentNetworkAccessDecisionDTO(
-                requestID: request.requestID,
-                decision: "timeout",
-                actor: "ui-modal-timeout"
-            )
-        case .dismissed:
-            return AgentNetworkAccessDecisionDTO(
-                requestID: request.requestID,
-                decision: "dismissed",
-                actor: "ui-modal-dismissed"
-            )
-        case .approved, .denied:
-            return AgentNetworkAccessDecisionDTO(
-                requestID: request.requestID,
-                decision: "deny",
-                actor: "ui-modal-deny"
-            )
-        }
     }
 }
diff --git a/ui/ui/Messaging/AppWorkspace.swift b/ui/ui/Messaging/AppWorkspace.swift
index 08095538..872c89b9 100644
--- a/ui/ui/Messaging/AppWorkspace.swift
+++ b/ui/ui/Messaging/AppWorkspace.swift
@@ -4,6 +4,5 @@ enum AppWorkspace: Equatable {
     case chats
     case plugins
     case messaging
-    case news
     case debugLogs
 }
diff --git a/ui/ui/News/NewsReaderStore.swift b/ui/ui/News/NewsReaderStore.swift
deleted file mode 100644
index e5ea5ddc..00000000
--- a/ui/ui/News/NewsReaderStore.swift
+++ /dev/null
@@ -1,126 +0,0 @@
-import Combine
-import DBRepository
-import Foundation
-import Structure
-
-@MainActor
-final class NewsReaderStore: ObservableObject {
-    static let shared = NewsReaderStore()
-
-    @Published private(set) var readers: [NewsReaderSpec] = []
-    @Published private(set) var items: [NewsItem] = []
-    @Published var selectedReaderID: String?
-    @Published private(set) var isRefreshing = false
-    @Published private(set) var lastError: String?
-
-    private var repository: DBRepository?
-    private let client: any NewsHTTPClient
-
-    init(client: any NewsHTTPClient = URLSessionNewsHTTPClient()) {
-        self.client = client
-    }
-
-    var selectedReader: NewsReaderSpec? {
-        readers.first { $0.id == selectedReaderID }
-    }
-
-    func configure(repository: DBRepository) async {
-        self.repository = repository
-        await reload()
-    }
-
-    func reload() async {
-        guard let repository else { return }
-        do {
-            readers = try await repository.listNewsReaders()
-            if selectedReaderID == nil {
-                selectedReaderID = readers.first?.id
-            }
-            if let id = selectedReaderID {
-                items = try await repository.listNewsItems(readerID: id)
-            } else {
-                items = []
-            }
-            lastError = nil
-        } catch {
-            lastError = error.localizedDescription
-        }
-    }
-
-    func select(id: String) async {
-        selectedReaderID = id
-        await reloadItems()
-        if let reader = selectedReader, shouldRefreshForSchedule(reader) {
-            await refreshSelected()
-        }
-    }
-
-    @discardableResult
-    func create(_ spec: NewsReaderSpec) async throws -> NewsReaderSpec {
-        guard let repository else {
-            throw NewsReaderError.notReady
-        }
-        var next = spec
-        next.updatedAt = .now
-        let items = try await NewsReaderRefresh.validateAndFetch(spec: next, client: client)
-        next.lastFetchedAt = .now
-        next.lastError = nil
-        try await repository.upsertNewsReader(next)
-        try await repository.replaceNewsItems(readerID: next.id, items: items)
-        await reload()
-        selectedReaderID = next.id
-        self.items = items
-        return next
-    }
-
-    func refreshSelected() async {
-        guard let repository, var reader = selectedReader else { return }
-        isRefreshing = true
-        defer { isRefreshing = false }
-        do {
-            let fetched = try await NewsReaderRefresh.validateAndFetch(spec: reader, client: client)
-            reader.lastFetchedAt = .now
-            reader.lastError = nil
-            reader.updatedAt = .now
-            try await repository.upsertNewsReader(reader)
-            try await repository.replaceNewsItems(readerID: reader.id, items: fetched)
-            items = fetched
-            lastError = nil
-            await reload()
-        } catch {
-            reader.lastError = error.localizedDescription
-            reader.updatedAt = .now
-            try? await repository.upsertNewsReader(reader)
-            lastError = error.localizedDescription
-            await reload()
-        }
-    }
-
-    func deleteSelected() async {
-        guard let repository, let id = selectedReaderID else { return }
-        try? await repository.deleteNewsReader(id: id)
-        selectedReaderID = nil
-        await reload()
-    }
-
-    private func reloadItems() async {
-        guard let repository, let id = selectedReaderID else {
-            items = []
-            return
-        }
-        items = (try? await repository.listNewsItems(readerID: id)) ?? []
-    }
-
-    private func shouldRefreshForSchedule(_ reader: NewsReaderSpec) -> Bool {
-        guard reader.schedule != .off else { return false }
-        guard let last = reader.lastFetchedAt else { return true }
-        switch reader.schedule {
-        case .off:
-            return false
-        case .hourly:
-            return Date().timeIntervalSince(last) >= 3_600
-        case .daily:
-            return Date().timeIntervalSince(last) >= 86_400
-        }
-    }
-}
diff --git a/ui/ui/News/NewsWorkspaceView.swift b/ui/ui/News/NewsWorkspaceView.swift
deleted file mode 100644
index ff8a4ab5..00000000
--- a/ui/ui/News/NewsWorkspaceView.swift
+++ /dev/null
@@ -1,132 +0,0 @@
-import SwiftUI
-import Structure
-
-struct NewsWorkspaceView: View {
-    @ObservedObject var store: NewsReaderStore
-
-    var body: some View {
-        VStack(spacing: 0) {
-            header
-            Divider()
-            if store.selectedReader == nil {
-                emptyState
-            } else {
-                itemList
-            }
-        }
-        .background(Color(red: 252.0 / 255.0, green: 252.0 / 255.0, blue: 250.0 / 255.0))
-    }
-
-    private var header: some View {
-        HStack(spacing: 12) {
-            VStack(alignment: .leading, spacing: 2) {
-                Text(store.selectedReader?.name ?? "News")
-                    .font(.headline)
-                if let reader = store.selectedReader {
-                    Text(headerSubtitle(reader))
-                        .font(.caption)
-                        .foregroundStyle(.secondary)
-                }
-            }
-            Spacer()
-            if store.selectedReader != nil {
-                Button {
-                    Task { await store.refreshSelected() }
-                } label: {
-                    if store.isRefreshing {
-                        ProgressView()
-                            .controlSize(.small)
-                    } else {
-                        Text("Refresh")
-                    }
-                }
-                .disabled(store.isRefreshing)
-                .buttonStyle(.bordered)
-            }
-        }
-        .padding(.horizontal, 24)
-        .padding(.vertical, 14)
-    }
-
-    private var emptyState: some View {
-        VStack(spacing: 10) {
-            Spacer()
-            Image(systemName: "newspaper")
-                .font(.system(size: 36))
-                .foregroundStyle(.secondary)
-            Text("No news lists yet")
-                .font(.title3.weight(.semibold))
-            Text("Create a News reader from Plugins. You can pick several topics and several sources.")
-                .font(.subheadline)
-                .foregroundStyle(.secondary)
-                .multilineTextAlignment(.center)
-                .frame(maxWidth: 420)
-            Spacer()
-        }
-        .frame(maxWidth: .infinity, maxHeight: .infinity)
-    }
-
-    private var itemList: some View {
-        ScrollView {
-            VStack(alignment: .leading, spacing: 16) {
-                if let error = store.selectedReader?.lastError ?? store.lastError, !error.isEmpty {
-                    Text(error)
-                        .font(.caption)
-                        .foregroundStyle(.red)
-                        .padding(12)
-                        .frame(maxWidth: .infinity, alignment: .leading)
-                        .background(Color.red.opacity(0.08), in: RoundedRectangle(cornerRadius: 10))
-                }
-                if store.selectedReader?.mode == .summaries, !store.items.isEmpty {
-                    VStack(alignment: .leading, spacing: 8) {
-                        Text("Summary")
-                            .font(.subheadline.weight(.semibold))
-                        Text(NewsReaderRefresh.digest(from: store.items))
-                            .font(.body)
-                            .textSelection(.enabled)
-                    }
-                    .padding(14)
-                    .frame(maxWidth: .infinity, alignment: .leading)
-                    .background(Color.white, in: RoundedRectangle(cornerRadius: 12))
-                }
-                ForEach(store.items) { item in
-                    VStack(alignment: .leading, spacing: 6) {
-                        Link(destination: URL(string: item.sourceURL) ?? URL(string: "https://example.com")!) {
-                            Text(item.title)
-                                .font(.body.weight(.semibold))
-                                .multilineTextAlignment(.leading)
-                        }
-                        HStack(spacing: 8) {
-                            Text(item.sourceLabel)
-                                .font(.caption)
-                                .foregroundStyle(.secondary)
-                            Link("Source", destination: URL(string: item.sourceURL) ?? URL(string: "https://example.com")!)
-                                .font(.caption.weight(.semibold))
-                        }
-                        if let summary = item.summary, !summary.isEmpty, store.selectedReader?.mode == .list {
-                            Text(summary)
-                                .font(.caption)
-                                .foregroundStyle(.secondary)
-                                .lineLimit(4)
-                        }
-                    }
-                    .padding(14)
-                    .frame(maxWidth: .infinity, alignment: .leading)
-                    .background(Color.white, in: RoundedRectangle(cornerRadius: 12))
-                }
-                if store.items.isEmpty, store.lastError == nil, store.selectedReader?.lastError == nil {
-                    Text("No articles yet. Refresh this list.")
-                        .font(.subheadline)
-                        .foregroundStyle(.secondary)
-                }
-            }
-            .padding(24)
-        }
-    }
-
-    private func headerSubtitle(_ reader: NewsReaderSpec) -> String {
-        let topics = reader.topics.isEmpty ? "All topics" : reader.topics.joined(separator: ", ")
-        let sources = "\(reader.sources.count) source\(reader.sources.count == 1 ? "" : "s")"
-        return "\(topics) · \(sources) · \(reader.mode.displayName) · \(reader.schedule.displayName)"
-    }
-}
diff --git a/ui/ui/Plugins/PluginCreationController.swift b/ui/ui/Plugins/PluginCreationController.swift
index 8888d399..c4228f2a 100644
--- a/ui/ui/Plugins/PluginCreationController.swift
+++ b/ui/ui/Plugins/PluginCreationController.swift
@@ -2,21 +2,24 @@ import Combine
 import DBRepository
 import Foundation
 import Structure
+import SwiftUI
 
 @MainActor
 final class PluginCreationController: ObservableObject {
     enum Phase: Equatable {
         case intro
-        case chooseType
-        case chooseVendor
-        case chooseName
-        case chooseNews
+        case goal
+        case skill
+        case preview
         case discoveringAuth
         case creating
         case collectCredentials(pluginID: String)
         case failed(step: PluginFactoryCreateInput.FailureStep, message: String, technicalDetail: String? = nil)
-        case succeeded(pluginID: String)
-        case succeededNews(readerID: String)
+        case succeeded(pluginID: String, outcome: SuccessOutcome)
+    }
+
+    enum SuccessOutcome: Equatable {
+        case plugin
     }
 
     struct ProgressStepState: Identifiable, Equatable {
@@ -35,22 +38,7 @@ final class PluginCreationController: ObservableObject {
     @Published private(set) var phase: Phase = .intro
     @Published private(set) var statusMessage = ""
     @Published private(set) var progressSteps: [ProgressStepState] = []
-    @Published var selectedType: PluginFactoryCreateInput.PluginType = .connector
-    @Published var selectedVendor: PluginFactoryCreateInput.ConnectorVendor = .slack
-    @Published var selectedScope: PluginFactoryCreateInput.ConnectorScope = .fullSync
-    @Published var customVendorName = ""
-    @Published var connectorName = ""
-    @Published private(set) var defaultNameReady = false
-    @Published var newsName = ""
-    @Published var selectedNewsTopics: Set<NewsPresetTopic> = []
-    @Published var extraNewsTopics: [String] = []
-    @Published var newsTopicDraft = ""
-    @Published var selectedNewsSources: Set<NewsPresetSource> = []
-    @Published var extraNewsURLs: [String] = []
-    @Published var newsURLDraft = ""
-    @Published var newsMode: NewsReaderMode = .list
-    @Published var newsMaxCount = 20
-    @Published var newsSchedule: NewsReaderSchedule = .off
+    @Published var skillDraft = PluginSkillDraft()
     @Published private(set) var credentialFields: [PluginCredentialFieldPresentation] = []
     @Published var credentialDrafts: [String: String] = [:]
 
@@ -59,8 +47,6 @@ final class PluginCreationController: ObservableObject {
     private var pollAfterSeq = 0
     private var pollTask: Task<Void, Never>?
     private var discoverTask: Task<Void, Never>?
-    private var namePrepareTask: Task<Void, Never>?
-    private var generatedConnectorName = ""
     private var pendingAuth: ConnectorAuthDiscovery?
     private var creationAPIKey: String?
     private var creationReviewerModelJSON: String?
@@ -69,27 +55,27 @@ final class PluginCreationController: ObservableObject {
     deinit {
         pollTask?.cancel()
         discoverTask?.cancel()
-        namePrepareTask?.cancel()
     }
 
-    var canConfirmName: Bool {
-        guard defaultNameReady else { return false }
-        let trimmed = connectorName.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !trimmed.isEmpty else { return false }
-        return (try? PluginID.normalized(trimmed)) != nil
+    var canContinueFromGoal: Bool {
+        !skillDraft.goal.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
     }
 
-    var canConfirmVendor: Bool {
-        guard selectedVendor.isSelectableInWizard else { return false }
-        if selectedVendor == .custom {
-            return !customVendorName.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
-        }
-        return true
+    var canContinueFromSkill: Bool {
+        guard canConfirmPluginName else { return false }
+        guard !skillDraft.purpose.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else { return false }
+        guard !skillDraft.examples.isEmpty else { return false }
+        guard skillDraft.examples.allSatisfy({
+            !$0.userSays.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+                && !$0.pluginDoes.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+        }) else { return false }
+        return skillDraft.buildBlockedReason == nil
     }
 
-    var canConfirmNews: Bool {
-        let nameOK = !newsName.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
-        return nameOK && !builtNewsSources().isEmpty
+    var canConfirmPluginName: Bool {
+        let trimmed = skillDraft.pluginName.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !trimmed.isEmpty else { return false }
+        return (try? PluginID.normalized(trimmed)) != nil
     }
 
     var canSaveCredentials: Bool {
@@ -104,281 +90,121 @@ final class PluginCreationController: ObservableObject {
         self.repository = repository
     }
 
+    func skillDraftBinding<T>(_ keyPath: WritableKeyPath<PluginSkillDraft, T>) -> Binding<T> {
+        Binding(
+            get: { self.skillDraft[keyPath: keyPath] },
+            set: { newValue in
+                var draft = self.skillDraft
+                draft[keyPath: keyPath] = newValue
+                self.skillDraft = draft
+            }
+        )
+    }
+
     func showIntro() {
         cancelPolling()
         discoverTask?.cancel()
-        namePrepareTask?.cancel()
         pendingAuth = nil
         phase = .intro
         statusMessage = ""
         progressSteps = []
         credentialFields = []
         credentialDrafts = [:]
-        selectedScope = .fullSync
-        connectorName = ""
-        generatedConnectorName = ""
-        defaultNameReady = false
+        skillDraft = PluginSkillDraft()
     }
 
     func beginCreate() {
         cancelPolling()
-        phase = .chooseType
+        phase = .goal
         statusMessage = ""
         progressSteps = []
     }
 
-    func selectType(_ type: PluginFactoryCreateInput.PluginType) {
-        selectedType = type
-    }
-
-    func confirmTypeSelection() {
-        if selectedType == .newsReader {
-            resetNewsDraft()
-            phase = .chooseNews
-            return
-        }
-        guard selectedType == .connector else {
-            phase = .failed(
-                step: .type,
-                message: "Custom plugins are not available yet."
+    func continueFromGoal() {
+        guard canContinueFromGoal else { return }
+        Task { @MainActor in
+            await PluginFactoryListStore.shared.reload()
+            var draft = skillDraft
+            PluginSkillDraftPlanner.applyGoal(
+                draft.goal,
+                to: &draft,
+                existingPluginIDs: PluginFactoryListStore.shared.pluginIDs
             )
-            return
+            skillDraft = draft
+            phase = .skill
         }
-        selectedVendor = .slack
-        refreshDefaultConnectorName()
-        phase = .chooseVendor
     }
 
-    func confirmVendor(
-        sessionID: String,
-        helperAPIKey: String?,
-        helperReviewerModelJSON: String?
-    ) {
-        selectedScope = .fullSync
-        creationSessionID = sessionID
-        creationAPIKey = helperAPIKey
-        creationReviewerModelJSON = helperReviewerModelJSON
-        defaultNameReady = false
-        phase = .chooseName
-        namePrepareTask?.cancel()
-        namePrepareTask = Task { @MainActor in
-            await PluginFactoryListStore.shared.reload()
-            guard !Task.isCancelled else { return }
-            refreshDefaultConnectorName()
-            defaultNameReady = true
-            startAuthDiscovery()
-        }
+    func continueToPreview() {
+        guard canContinueFromSkill else { return }
+        phase = .preview
     }
 
-    func confirmConnectorName() {
-        guard canConfirmName else { return }
-        if let pendingAuth {
-            presentCredentialsOrFail(auth: pendingAuth)
-        } else {
-            phase = .discoveringAuth
-            statusMessage = "Reading how this service authenticates…"
-        }
-    }
-
-    func goBackToTypeSelection() {
-        namePrepareTask?.cancel()
+    func goBackToGoal() {
         discoverTask?.cancel()
         pendingAuth = nil
-        defaultNameReady = false
-        phase = .chooseType
+        phase = .goal
     }
 
-    func goBackToVendor() {
-        namePrepareTask?.cancel()
+    func goBackToSkill() {
         discoverTask?.cancel()
         pendingAuth = nil
-        defaultNameReady = false
-        phase = .chooseVendor
+        phase = .skill
     }
 
-    func addNewsTopic() {
-        let topic = newsTopicDraft.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !topic.isEmpty else { return }
-        if !extraNewsTopics.contains(where: { $0.compare(topic, options: .caseInsensitive) == .orderedSame }) {
-            extraNewsTopics.append(topic)
+    func addExample() {
+        mutateSkillDraft {
+            $0.examples.append(PluginSkillDraft.Example(userSays: "", pluginDoes: ""))
         }
-        newsTopicDraft = ""
-    }
-
-    func removeNewsTopic(_ topic: String) {
-        extraNewsTopics.removeAll { $0 == topic }
-    }
-
-    func addNewsURL() {
-        let url = newsURLDraft.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !url.isEmpty else { return }
-        extraNewsURLs.append(url)
-        newsURLDraft = ""
     }
 
-    func removeNewsURL(_ url: String) {
-        extraNewsURLs.removeAll { $0 == url }
+    func removeExample(id: String) {
+        mutateSkillDraft { $0.examples.removeAll { $0.id == id } }
     }
 
-    func startNewsCreation() {
-        let spec = NewsReaderSpec(
-            name: newsName,
-            topics: builtNewsTopics(),
-            sources: builtNewsSources(),
-            mode: newsMode,
-            maxCount: newsMaxCount,
-            schedule: newsSchedule
-        )
-        if let blocked = spec.sources.compactMap({ source -> (NewsSource, String)? in
-            guard let url = URL(string: source.url),
-                  let reason = NewsPaywall.preflightRejection(url: url) else { return nil }
-            return (source, reason)
-        }).first {
-            phase = .failed(
-                step: .news,
-                message: NewsReaderError.paywalled(url: blocked.0.url, detail: blocked.1).errorDescription
-                    ?? "This source is behind a paywall, which is not supported yet."
-            )
-            return
-        }
-        phase = .creating
-        statusMessage = "Checking sources…"
-        progressSteps = [
-            ProgressStepState(id: "sources", title: "Check sources for paywalls", status: .active),
-            ProgressStepState(id: "fetch", title: "Fetch articles with source links", status: .pending),
-        ]
-        pollTask?.cancel()
-        pollTask = Task { @MainActor in
-            do {
-                let saved = try await NewsReaderStore.shared.create(spec)
-                setProgressStep("sources", status: .completed)
-                setProgressStep("fetch", status: .completed)
-                phase = .succeededNews(readerID: saved.id)
-            } catch let error as NewsReaderError {
-                setProgressStep("sources", status: .failed)
-                phase = .failed(
-                    step: .news,
-                    message: error.localizedDescription,
-                    technicalDetail: String(describing: error)
-                )
-            } catch {
-                setProgressStep("sources", status: .failed)
-                phase = .failed(
-                    step: .news,
-                    message: error.localizedDescription
-                )
-            }
+    func updateExample(id: String, userSays: String? = nil, pluginDoes: String? = nil) {
+        mutateSkillDraft { draft in
+            guard let index = draft.examples.firstIndex(where: { $0.id == id }) else { return }
+            if let userSays { draft.examples[index].userSays = userSays }
+            if let pluginDoes { draft.examples[index].pluginDoes = pluginDoes }
         }
     }
 
-    func builtNewsTopics() -> [String] {
-        selectedNewsTopics.map(\.displayName) + extraNewsTopics
-    }
-
-    func builtNewsSources() -> [NewsSource] {
-        var sources = selectedNewsSources.map(\.source)
-        for raw in extraNewsURLs + [newsURLDraft] {
-            let trimmed = raw.trimmingCharacters(in: .whitespacesAndNewlines)
-            guard !trimmed.isEmpty else { continue }
-            let normalized = NewsSourceURL.canonicalFetchURL(
-                URL(string: trimmed.contains("://") ? trimmed : "https://\(trimmed)")
-                    ?? URL(string: "https://news.google.com/rss")!
-            ).absoluteString
-            sources.append(NewsSource(label: hostLabel(normalized), url: normalized))
+    func toggleTrigger(_ trigger: PluginSkillDraft.Trigger) {
+        mutateSkillDraft { draft in
+            guard draft.isTriggerAvailable(trigger) else { return }
+            if draft.triggers.contains(trigger) {
+                draft.triggers.remove(trigger)
+            } else {
+                draft.triggers.insert(trigger)
+            }
         }
-        var seen = Set<String>()
-        return sources.filter { seen.insert($0.url).inserted }
-    }
-
-    private func resetNewsDraft() {
-        newsName = ""
-        selectedNewsTopics = []
-        extraNewsTopics = []
-        newsTopicDraft = ""
-        selectedNewsSources = []
-        extraNewsURLs = []
-        newsURLDraft = ""
-        newsMode = .list
-        newsMaxCount = 20
-        newsSchedule = .off
     }
 
-    private func hostLabel(_ urlString: String) -> String {
-        URL(string: urlString)?.host ?? urlString
+    private func mutateSkillDraft(_ transform: (inout PluginSkillDraft) -> Void) {
+        var draft = skillDraft
+        transform(&draft)
+        skillDraft = draft
     }
 
-    func startCreation(
+    func confirmPreview(
         sessionID: String,
         helperAPIKey: String?,
         helperReviewerModelJSON: String?
     ) {
-        guard selectedVendor.isSelectableInWizard else {
-            phase = .failed(
-                step: .vendor,
-                message: "Only Slack connectors can be created right now."
-            )
-            return
-        }
-        guard let helperAPIKey, !helperAPIKey.isEmpty else {
-            phase = .failed(
-                step: .vendor,
-                message: "Add an API key in Settings before creating a plugin."
-            )
-            return
-        }
-        guard let pluginID = normalizedConnectorName(),
-              let auth = pendingAuth
-        else {
-            phase = .failed(
-                step: .name,
-                message: "Name this connector and save its credentials before creating it."
-            )
-            return
-        }
-        guard auth.authScheme.isSupportedInWizard else {
-            phase = .failed(
-                step: .auth,
-                message: "OAuth connectors are not available yet. Use a bot token or API key."
-            )
+        creationSessionID = sessionID
+        creationAPIKey = helperAPIKey
+        creationReviewerModelJSON = helperReviewerModelJSON
+
+        if skillDraft.plannedKind == .messagingConnector {
+            phase = .discoveringAuth
+            statusMessage = "Reading how this service authenticates…"
+            resetProgressSteps()
+            startAuthDiscovery()
             return
         }
 
-        selectedScope = .fullSync
-        cancelPolling()
-        phase = .creating
-        statusMessage = "Starting connector creation…"
-        resetProgressSteps()
-        pollAfterSeq = 0
-
-        let input = PluginFactoryCreateInput.makeConnector(
-            vendor: selectedVendor,
-            pluginID: pluginID,
-            auth: auth,
-            customVendorName: selectedVendor == .custom ? customVendorName : nil,
-            scope: selectedScope,
-            userDescription: ""
-        )
-
-        pollTask = Task { @MainActor in
-            do {
-                let inputJSON = try input.encodedJSON()
-                let handle = try await WorkflowRuntimeClient.shared.startWorkflow(
-                    WorkflowStartRequest(
-                        kind: .pluginFactoryCreate,
-                        sessionID: sessionID,
-                        agentID: "ui",
-                        inputJSON: inputJSON,
-                        principal: .agent(sessionID: sessionID, agentID: "ui"),
-                        helperAPIKey: helperAPIKey,
-                        helperReviewerModelJSON: helperReviewerModelJSON
-                    )
-                )
-                workflowID = handle.workflowID
-                await pollUntilTerminal()
-            } catch {
-                phase = .failed(step: .creating, message: error.localizedDescription)
-            }
-        }
+        startFactoryCreation()
     }
 
     func saveCredentialsAndFinish() {
@@ -390,14 +216,10 @@ final class PluginCreationController: ObservableObject {
                 drafts: credentialDrafts
             )
             markProgressCompleted("credentials")
-            startCreation(
-                sessionID: creationSessionID,
-                helperAPIKey: creationAPIKey,
-                helperReviewerModelJSON: creationReviewerModelJSON
-            )
+            startFactoryCreation()
         } catch {
             phase = .failed(
-                step: .auth,
+                step: .credentials,
                 message: "Could not save credentials: \(error.localizedDescription)"
             )
         }
@@ -407,13 +229,11 @@ final class PluginCreationController: ObservableObject {
         switch phase {
         case .failed(let step, _, _):
             switch step {
-            case .type: phase = .chooseType
-            case .news: phase = .chooseNews
-            case .name: phase = .chooseName
-            case .auth: phase = .chooseName
-            case .vendor, .description, .creating:
-                selectedVendor = .slack
-                phase = .chooseVendor
+            case .goal: phase = .goal
+            case .skill: phase = .skill
+            case .preview: phase = .preview
+            case .credentials: phase = .preview
+            case .build: phase = .preview
             }
         default:
             phase = .intro
@@ -424,13 +244,59 @@ final class PluginCreationController: ObservableObject {
         showIntro()
     }
 
+    private func startFactoryCreation() {
+        guard let creationAPIKey, !creationAPIKey.isEmpty else {
+            phase = .failed(
+                step: .build,
+                message: "Add an API key in Settings before creating a plugin."
+            )
+            return
+        }
+        do {
+            let input = try PluginFactoryCreateInput.makeFromSkillDraft(skillDraft, auth: pendingAuth)
+            cancelPolling()
+            phase = .creating
+            statusMessage = "Building your plugin…"
+            resetProgressSteps()
+            pollAfterSeq = 0
+
+            pollTask = Task { @MainActor in
+                do {
+                    let inputJSON = try input.encodedJSON()
+                    let handle = try await WorkflowRuntimeClient.shared.startWorkflow(
+                        WorkflowStartRequest(
+                            kind: .pluginFactoryCreate,
+                            sessionID: creationSessionID,
+                            agentID: "ui",
+                            inputJSON: inputJSON,
+                            principal: .agent(sessionID: creationSessionID, agentID: "ui"),
+                            helperAPIKey: creationAPIKey,
+                            helperReviewerModelJSON: creationReviewerModelJSON
+                        )
+                    )
+                    workflowID = handle.workflowID
+                    await pollUntilTerminal()
+                } catch {
+                    phase = .failed(step: .build, message: error.localizedDescription)
+                }
+            }
+        } catch {
+            phase = .failed(step: .skill, message: error.localizedDescription)
+        }
+    }
+
     private func resetProgressSteps() {
         progressSteps = [
-            ProgressStepState(id: "docs", title: "Read vendor API docs", status: .pending),
-            ProgressStepState(id: "factory", title: "Build and test plugin", status: .pending),
+            ProgressStepState(id: "skill", title: "Write SKILL.md", status: .completed),
+            ProgressStepState(id: "docs", title: "Read API docs", status: .pending),
+            ProgressStepState(id: "factory", title: "Build guest program", status: .pending),
             ProgressStepState(id: "review", title: "Safety review", status: .pending),
-            ProgressStepState(id: "credentials", title: "Save credentials to Keychain", status: .pending),
+            ProgressStepState(id: "trial", title: "Trial run", status: .pending),
+            ProgressStepState(id: "credentials", title: "Save credentials", status: .pending),
         ]
+        if skillDraft.plannedKind == .customCapability {
+            setProgressStep("docs", status: .completed)
+        }
     }
 
     private func setProgressStep(_ id: String, status: ProgressStepState.Status) {
@@ -450,16 +316,15 @@ final class PluginCreationController: ObservableObject {
         switch stage?.lowercased() {
         case "crawl", "docs":
             setProgressStep("docs", status: .failed)
-        case "factory", "build", "review":
+        case "factory", "build":
             markProgressCompleted("docs")
             setProgressStep("factory", status: .failed)
+        case "review":
+            markProgressCompleted("docs")
+            markProgressCompleted("factory")
             setProgressStep("review", status: .failed)
         default:
-            if progressSteps.first(where: { $0.id == "docs" })?.status == .completed {
-                setProgressStep("factory", status: .failed)
-            } else {
-                setProgressStep("docs", status: .failed)
-            }
+            setProgressStep("factory", status: .failed)
         }
     }
 
@@ -476,6 +341,7 @@ final class PluginCreationController: ObservableObject {
                 markProgressCompleted("docs")
                 markProgressCompleted("factory")
                 markProgressCompleted("review")
+                markProgressCompleted("trial")
             default:
                 break
             }
@@ -488,10 +354,11 @@ final class PluginCreationController: ObservableObject {
             if message.contains("review decision=approved") {
                 markProgressCompleted("factory")
                 markProgressCompleted("review")
+                markProgressActive("trial")
             }
             if message.contains("review decision=rejected") || message.contains("review rejected=") {
                 markProgressCompleted("factory")
-                markProgressActive("review")
+                setProgressStep("review", status: .failed)
             }
         default:
             break
@@ -520,30 +387,27 @@ final class PluginCreationController: ObservableObject {
                     markProgressCompleted("docs")
                     markProgressCompleted("factory")
                     markProgressCompleted("review")
+                    markProgressCompleted("trial")
                     await PluginFactoryListStore.shared.reload()
                     if let pluginID = parseSuccessPluginID(result.resultJSON) {
                         markProgressCompleted("credentials")
-                        phase = .succeeded(pluginID: pluginID)
+                        phase = .succeeded(pluginID: pluginID, outcome: .plugin)
+                    } else if let saved = PluginFactoryListStore.shared.releases.first {
+                        markProgressCompleted("credentials")
+                        phase = .succeeded(pluginID: saved.pluginID, outcome: .plugin)
                     } else {
-                        if let saved = PluginFactoryListStore.shared.releases.first {
-                            markProgressCompleted("credentials")
-                            phase = .succeeded(pluginID: saved.pluginID)
-                        } else {
-                            phase = .failed(
-                                step: .creating,
-                                message: """
-                                The connector was not saved. Creation reported success but no plugin release was found.
-                                """,
-                                technicalDetail: result.resultJSON
-                            )
-                        }
+                        phase = .failed(
+                            step: .build,
+                            message: "The plugin was not saved. Creation reported success but no release was found.",
+                            technicalDetail: result.resultJSON
+                        )
                     }
                     cancelPolling()
                     return
                 case .failed:
                     let stage = result.events.last(where: { $0.kind == "log" })?.stage
                     markProgressFailed(fromStage: stage)
-                    let raw = result.errorMessage ?? "Connector creation failed."
+                    let raw = result.errorMessage ?? "Plugin creation failed."
                     let presentation = PluginFactoryCreateFailureMessage.presentation(raw)
                     phase = .failed(
                         step: PluginFactoryCreateInput.failureStep(forStage: stage),
@@ -555,8 +419,8 @@ final class PluginCreationController: ObservableObject {
                 case .cancelled:
                     markProgressFailed(fromStage: "factory")
                     phase = .failed(
-                        step: .creating,
-                        message: "The connector was not saved. Creation was cancelled before it finished."
+                        step: .build,
+                        message: "Plugin creation was cancelled before it finished."
                     )
                     cancelPolling()
                     return
@@ -564,7 +428,7 @@ final class PluginCreationController: ObservableObject {
                     break
                 }
             } catch {
-                phase = .failed(step: .creating, message: error.localizedDescription)
+                phase = .failed(step: .build, message: error.localizedDescription)
                 cancelPolling()
                 return
             }
@@ -581,29 +445,13 @@ final class PluginCreationController: ObservableObject {
         return result.pluginID
     }
 
-    private func refreshDefaultConnectorName() {
-        let existing = PluginFactoryListStore.shared.pluginIDs
-        let generated = ConnectorPluginNaming.defaultPluginID(
-            vendor: selectedVendor,
-            existingIDs: existing
-        )
-        if connectorName.isEmpty
-            || ConnectorPluginNaming.isGeneratedDefault(pluginID: connectorName, vendor: selectedVendor)
-            || connectorName == generatedConnectorName {
-            connectorName = generated
-        }
-        generatedConnectorName = generated
-    }
-
-    private func normalizedConnectorName() -> String? {
-        let trimmed = connectorName.trimmingCharacters(in: .whitespacesAndNewlines)
-        return try? PluginID.normalized(trimmed).rawValue
-    }
-
     private func startAuthDiscovery() {
         discoverTask?.cancel()
         pendingAuth = nil
-        let vendor = selectedVendor
+        guard let vendor = skillDraft.inferredConnectorVendor else {
+            phase = .failed(step: .skill, message: "Could not determine which messaging service this plugin targets.")
+            return
+        }
         let sessionID = creationSessionID
         let apiKey = creationAPIKey
         let reviewerJSON = creationReviewerModelJSON
@@ -674,20 +522,20 @@ final class PluginCreationController: ObservableObject {
     private func presentCredentialsOrFail(auth: ConnectorAuthDiscovery) {
         guard auth.authScheme.isSupportedInWizard else {
             phase = .failed(
-                step: .auth,
+                step: .credentials,
                 message: "OAuth connectors are not available yet. Use a bot token or API key."
             )
             return
         }
-        guard let pluginID = normalizedConnectorName() else {
-            phase = .chooseName
+        guard let pluginID = try? skillDraft.normalizedPluginID() else {
+            phase = .skill
             return
         }
         let descriptors = auth.secrets.map(\.descriptor)
         guard !descriptors.isEmpty else {
             phase = .failed(
-                step: .auth,
-                message: "Could not determine which credentials this connector needs."
+                step: .credentials,
+                message: "Could not determine which credentials this plugin needs."
             )
             return
         }
@@ -704,7 +552,7 @@ final class PluginCreationController: ObservableObject {
             let env = PluginSecretDevelopmentSource.resolve(pluginID: pluginID, fieldID: field.id) ?? ""
             return (field.id, env)
         })
-        statusMessage = auth.setupHint ?? "Enter the credentials this connector needs. They are stored in Keychain on your Mac."
+        statusMessage = auth.setupHint ?? "Enter the credentials this plugin needs. They are stored in Keychain on your Mac."
         phase = .collectCredentials(pluginID: pluginID)
     }
 
diff --git a/ui/ui/Plugins/PluginsWorkspaceView.swift b/ui/ui/Plugins/PluginsWorkspaceView.swift
index 5034315c..a3e8a3b3 100644
--- a/ui/ui/Plugins/PluginsWorkspaceView.swift
+++ b/ui/ui/Plugins/PluginsWorkspaceView.swift
@@ -8,7 +8,6 @@ struct PluginsWorkspaceView: View {
     let helperReviewerModelJSON: String?
     let sessionID: String
     let onOpenMessagingConnector: (String) -> Void
-    var onOpenNewsReader: (String) -> Void = { _ in }
 
     var body: some View {
         ZStack {
@@ -33,8 +32,8 @@ struct PluginsWorkspaceView: View {
             isPresented: true,
             minWidth: 400,
             minHeight: 0,
-            maxWidth: 520,
-            maxHeight: controller.phase == .chooseNews ? 720 : 560,
+            maxWidth: 560,
+            maxHeight: modalMaxHeight,
             onBackdropDismiss: canDismiss ? { controller.showIntro() } : nil,
             onEscape: canDismiss ? { controller.showIntro() } : nil,
             header: {
@@ -57,6 +56,13 @@ struct PluginsWorkspaceView: View {
         )
     }
 
+    private var modalMaxHeight: CGFloat {
+        switch controller.phase {
+        case .skill, .preview: return 720
+        default: return 560
+        }
+    }
+
     private var canDismiss: Bool {
         switch controller.phase {
         case .creating, .discoveringAuth: return false
@@ -67,119 +73,59 @@ struct PluginsWorkspaceView: View {
     private var modalTitle: String {
         switch controller.phase {
         case .intro: return "Create a plugin"
-        case .chooseType: return "Create a plugin"
-        case .chooseVendor: return "Choose a vendor"
-        case .chooseName: return "Name this connector"
-        case .chooseNews: return "News list"
+        case .goal: return "What should it do?"
+        case .skill: return "Define the skill"
+        case .preview: return "Preview"
         case .discoveringAuth: return "Reading authentication docs"
-        case .creating: return controller.selectedType == .newsReader ? "Creating news list" : "Creating connector"
-        case .collectCredentials: return "Connector credentials"
-        case .failed: return controller.selectedType == .newsReader ? "Could not create news list" : "Could not create connector"
-        case .succeeded: return "Connector ready"
-        case .succeededNews: return "News list ready"
+        case .creating: return creatingTitle
+        case .collectCredentials: return "Plugin credentials"
+        case .failed: return failureTitle
+        case .succeeded(_, let outcome):
+            return "Plugin ready"
         }
     }
 
+    private var creatingTitle: String {
+        switch controller.skillDraft.plannedKind {
+        case .messagingConnector: return "Creating connector"
+        case .customCapability: return "Building plugin"
+        }
+    }
+
+    private var failureTitle: String {
+        return "Could not create plugin"
+    }
+
     @ViewBuilder
     private var modalBody: some View {
         switch controller.phase {
         case .intro:
             Text("""
-            A plugin is a small program that extends the capabilities of Derrick. This form will guide you through the process of building your own unique and secure plugins.
+            Describe what you want Derrick to do. Derrick will draft a skill, show you a preview, and build a secure plugin package.
             """)
             .font(.body)
             .fixedSize(horizontal: false, vertical: true)
 
-        case .chooseType:
+        case .goal:
             VStack(alignment: .leading, spacing: 10) {
-                Text("What kind of plugin do you want?")
+                Text("What do you want Derrick to do?")
                     .font(.subheadline)
                     .foregroundStyle(.secondary)
-                typeButton(
-                    title: "Connector",
-                    subtitle: "Messaging integration (Slack)",
-                    type: .connector,
-                    enabled: true
-                )
-                typeButton(
-                    title: "News reader",
-                    subtitle: "Saved lists from topics and sources",
-                    type: .newsReader,
-                    enabled: true
-                )
-                typeButton(
-                    title: "Custom",
-                    subtitle: "Coming soon",
-                    type: .custom,
-                    enabled: false
+                TextField(
+                    "e.g. Send Slack messages from Messaging, or fetch tech headlines",
+                    text: controller.skillDraftBinding(\.goal),
+                    axis: .vertical
                 )
+                .textFieldStyle(.roundedBorder)
+                .lineLimit(3...6)
+                .accessibilityIdentifier("plugin-goal-field")
             }
 
-        case .chooseVendor:
-            VStack(alignment: .leading, spacing: 10) {
-                Text("Which service should this connector use?")
-                    .font(.subheadline)
-                    .foregroundStyle(.secondary)
-                LazyVGrid(columns: [GridItem(.adaptive(minimum: 120), spacing: 8)], spacing: 8) {
-                    ForEach(PluginFactoryCreateInput.ConnectorVendor.allCases, id: \.self) { vendor in
-                        let enabled = vendor.isSelectableInWizard
-                        Button {
-                            guard enabled else { return }
-                            controller.selectedVendor = vendor
-                        } label: {
-                            VStack(spacing: 4) {
-                                Text(vendor.displayName)
-                                    .font(.subheadline.weight(.medium))
-                                if !enabled {
-                                    Text("Soon")
-                                        .font(.caption2)
-                                        .foregroundStyle(.secondary)
-                                }
-                            }
-                            .frame(maxWidth: .infinity)
-                            .padding(.vertical, 10)
-                            .background(
-                                enabled && controller.selectedVendor == vendor
-                                    ? Color.accentColor.opacity(0.15)
-                                    : Color.primary.opacity(enabled ? 0.05 : 0.03)
-                            )
-                            .foregroundStyle(enabled ? .primary : .secondary)
-                            .clipShape(RoundedRectangle(cornerRadius: 10))
-                        }
-                        .buttonStyle(.plain)
-                        .disabled(!enabled)
-                        .accessibilityLabel(enabled ? vendor.displayName : "\(vendor.displayName), coming soon")
-                    }
-                }
-                if controller.selectedVendor == .custom {
-                    TextField("Vendor name", text: $controller.customVendorName)
-                        .textFieldStyle(.roundedBorder)
-                }
-                Text("This connector lists conversations as tabs, including reply threads, then sends and receives new messages.")
-                    .font(.caption)
-                    .foregroundStyle(.secondary)
-                    .fixedSize(horizontal: false, vertical: true)
-                    .padding(.top, 4)
-                if controller.selectedVendor == .slack {
-                    Text(ConnectorReplyThreadAccessMessage.slackSetupHint)
-                        .font(.caption)
-                        .foregroundStyle(.secondary)
-                        .fixedSize(horizontal: false, vertical: true)
-                }
-            }
+        case .skill:
+            skillBuilderForm
 
-        case .chooseName:
-            VStack(alignment: .leading, spacing: 10) {
-                Text("Give this connector a name. You can change the default.")
-                    .font(.subheadline)
-                    .foregroundStyle(.secondary)
-                TextField("Connector name", text: $controller.connectorName)
-                    .textFieldStyle(.roundedBorder)
-                    .accessibilityIdentifier("connector-plugin-name")
-            }
-
-        case .chooseNews:
-            newsReaderForm
+        case .preview:
+            previewForm
 
         case .discoveringAuth, .creating:
             VStack(alignment: .leading, spacing: 14) {
@@ -198,7 +144,7 @@ struct PluginsWorkspaceView: View {
                     .font(.subheadline)
                     .foregroundStyle(.secondary)
                     .fixedSize(horizontal: false, vertical: true)
-                if controller.selectedVendor == .slack {
+                if controller.skillDraft.inferredConnectorVendor == .slack {
                     Text(ConnectorReplyThreadAccessMessage.slackSetupHint)
                         .font(.caption)
                         .foregroundStyle(.secondary)
@@ -210,58 +156,10 @@ struct PluginsWorkspaceView: View {
             }
 
         case .failed(_, let message, let technicalDetail):
-            VStack(alignment: .leading, spacing: 10) {
-                if controller.selectedType == .newsReader {
-                    Label(
-                        message.localizedCaseInsensitiveContains("paywall")
-                            ? "Blocked because of a paywall"
-                            : "News list was not created",
-                        systemImage: "exclamationmark.triangle.fill"
-                    )
-                    .font(.subheadline.weight(.semibold))
-                    .foregroundStyle(message.localizedCaseInsensitiveContains("paywall") ? Color.orange : Color.secondary)
-                    .accessibilityIdentifier(
-                        message.localizedCaseInsensitiveContains("paywall")
-                            ? "news-paywall-blocked"
-                            : "news-create-failed"
-                    )
-                    if message.localizedCaseInsensitiveContains("paywall") {
-                        Text(NewsPaywall.userWarning)
-                            .font(.caption)
-                            .foregroundStyle(.secondary)
-                            .fixedSize(horizontal: false, vertical: true)
-                    }
-                } else {
-                    Label("Nothing was installed", systemImage: "minus.circle")
-                        .font(.subheadline.weight(.semibold))
-                        .foregroundStyle(.secondary)
-                    Text("Your sidebar and Messaging are unchanged.")
-                        .font(.caption)
-                        .foregroundStyle(.secondary)
-                }
-                Text(message)
-                    .font(.body)
-                    .fixedSize(horizontal: false, vertical: true)
-                    .padding(.top, 4)
-                if let technicalDetail, !technicalDetail.isEmpty {
-                    DisclosureGroup("Technical details") {
-                        Text(technicalDetail)
-                            .font(.caption)
-                            .foregroundStyle(.secondary)
-                            .fixedSize(horizontal: false, vertical: true)
-                            .textSelection(.enabled)
-                    }
-                }
-            }
+            failureBody(message: message, technicalDetail: technicalDetail)
 
-        case .succeeded(let pluginID):
-            Text("Your connector /\(pluginID) is ready. Open it to start talking in Messaging.")
-                .font(.body)
-                .fixedSize(horizontal: false, vertical: true)
-        case .succeededNews:
-            Text("Your news list is ready. Every article includes a source link.")
-                .font(.body)
-                .fixedSize(horizontal: false, vertical: true)
+        case .succeeded(let pluginID, let outcome):
+            successBody(pluginID: pluginID, outcome: outcome)
         }
     }
 
@@ -271,62 +169,48 @@ struct PluginsWorkspaceView: View {
         case .intro:
             HStack {
                 Spacer()
-                Button("Create plugin") { controller.beginCreate() }
+                Button("Begin") { controller.beginCreate() }
                     .buttonStyle(ModalPrimaryButtonStyle())
                     .keyboardShortcut(.defaultAction)
             }
 
-        case .chooseType:
+        case .goal:
             HStack {
                 Button("Back") { controller.showIntro() }
                     .buttonStyle(ModalSecondaryButtonStyle())
                 Spacer()
-                Button("Continue") { controller.confirmTypeSelection() }
+                Button("Continue") { controller.continueFromGoal() }
                     .buttonStyle(ModalPrimaryButtonStyle())
-                    .disabled(
-                        controller.selectedType != .connector
-                            && controller.selectedType != .newsReader
-                    )
+                    .disabled(!controller.canContinueFromGoal)
                     .keyboardShortcut(.defaultAction)
             }
 
-        case .chooseVendor:
-            HStack {
-                Button("Back") { controller.goBackToTypeSelection() }
-                    .buttonStyle(ModalSecondaryButtonStyle())
-                Spacer()
-                Button("Continue") {
-                    controller.confirmVendor(
-                        sessionID: sessionID,
-                        helperAPIKey: helperAPIKey,
-                        helperReviewerModelJSON: helperReviewerModelJSON
-                    )
-                }
-                .buttonStyle(ModalPrimaryButtonStyle())
-                .disabled(!sessionReady || !controller.canConfirmVendor)
-                .keyboardShortcut(.defaultAction)
-            }
-
-        case .chooseName:
+        case .skill:
             HStack {
-                Button("Back") { controller.goBackToVendor() }
+                Button("Back") { controller.goBackToGoal() }
                     .buttonStyle(ModalSecondaryButtonStyle())
                 Spacer()
-                Button("Continue") { controller.confirmConnectorName() }
+                Button("Preview") { controller.continueToPreview() }
                     .buttonStyle(ModalPrimaryButtonStyle())
-                    .disabled(!controller.canConfirmName)
+                    .disabled(!controller.canContinueFromSkill)
                     .keyboardShortcut(.defaultAction)
             }
 
-        case .chooseNews:
+        case .preview:
             HStack {
-                Button("Back") { controller.goBackToTypeSelection() }
+                Button("Back") { controller.goBackToSkill() }
                     .buttonStyle(ModalSecondaryButtonStyle())
                 Spacer()
-                Button("Create") { controller.startNewsCreation() }
-                    .buttonStyle(ModalPrimaryButtonStyle())
-                    .disabled(!controller.canConfirmNews)
-                    .keyboardShortcut(.defaultAction)
+                Button(buildButtonTitle) {
+                    controller.confirmPreview(
+                        sessionID: sessionID,
+                        helperAPIKey: helperAPIKey,
+                        helperReviewerModelJSON: helperReviewerModelJSON
+                    )
+                }
+                .buttonStyle(ModalPrimaryButtonStyle())
+                .disabled(!sessionReady || !controller.canContinueFromSkill)
+                .keyboardShortcut(.defaultAction)
             }
 
         case .discoveringAuth, .creating:
@@ -352,28 +236,299 @@ struct PluginsWorkspaceView: View {
                     .buttonStyle(ModalSecondaryButtonStyle())
             }
 
-        case .succeeded(let pluginID):
+        case .succeeded(let pluginID, let outcome):
             HStack {
-                Button("Done") { controller.dismissSuccess() }
-                    .buttonStyle(ModalSecondaryButtonStyle())
+                if outcome != .plugin || controller.skillDraft.plannedKind == .messagingConnector {
+                    Button("Done") { controller.dismissSuccess() }
+                        .buttonStyle(ModalSecondaryButtonStyle())
+                }
                 Spacer()
-                Button("Open connector") {
-                    onOpenMessagingConnector(pluginID)
+                switch outcome {
+                case .plugin where controller.skillDraft.plannedKind == .messagingConnector:
+                    Button("Open connector") {
+                        onOpenMessagingConnector(pluginID)
+                    }
+                    .buttonStyle(ModalPrimaryButtonStyle())
+                    .keyboardShortcut(.defaultAction)
+                case .plugin:
+                    Button("Done") { controller.dismissSuccess() }
+                        .buttonStyle(ModalPrimaryButtonStyle())
+                        .keyboardShortcut(.defaultAction)
                 }
-                .buttonStyle(ModalPrimaryButtonStyle())
-                .keyboardShortcut(.defaultAction)
             }
 
-        case .succeededNews(let readerID):
+        }
+    }
+
+    private var buildButtonTitle: String {
+        "Build plugin"
+    }
+
+    private var skillBuilderForm: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: 16) {
+                plannedKindBadge
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("Purpose")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                    TextField("What this plugin does", text: controller.skillDraftBinding(\.purpose), axis: .vertical)
+                        .textFieldStyle(.roundedBorder)
+                        .lineLimit(2...4)
+                }
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("When to use")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                    FlowLayout(spacing: 8) {
+                        ForEach(PluginSkillDraft.Trigger.allCases, id: \.self) { trigger in
+                            triggerChip(trigger)
+                        }
+                    }
+                }
+
+                examplesSection
+
+                nameFieldSection
+
+                if let blocked = controller.skillDraft.buildBlockedReason {
+                    Text(blocked)
+                        .font(.caption)
+                        .foregroundStyle(.orange)
+                        .fixedSize(horizontal: false, vertical: true)
+                }
+            }
+        }
+    }
+
+    private var plannedKindBadge: some View {
+        let (label, icon) = plannedKindPresentation
+        return Label(label, systemImage: icon)
+            .font(.caption.weight(.semibold))
+            .foregroundStyle(.secondary)
+            .padding(.horizontal, 10)
+            .padding(.vertical, 6)
+            .background(Color.primary.opacity(0.05), in: Capsule())
+    }
+
+    private var plannedKindPresentation: (String, String) {
+        switch controller.skillDraft.plannedKind {
+        case .messagingConnector:
+            let vendor = controller.skillDraft.inferredConnectorVendor?.displayName ?? "Messaging"
+            return ("\(vendor) connector", "bubble.left.and.bubble.right")
+        case .customCapability:
+            return ("Custom capability", "wand.and.stars")
+        }
+    }
+
+    private var examplesSection: some View {
+        VStack(alignment: .leading, spacing: 8) {
             HStack {
-                Button("Done") { controller.dismissSuccess() }
-                    .buttonStyle(ModalSecondaryButtonStyle())
+                Text("Examples")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
                 Spacer()
-                Button("Open news list") {
-                    onOpenNewsReader(readerID)
+                Button("Add example") { controller.addExample() }
+                    .font(.caption)
+            }
+            ForEach(controller.skillDraft.examples) { example in
+                VStack(alignment: .leading, spacing: 6) {
+                    TextField("You say…", text: exampleBinding(example.id, field: .userSays))
+                        .textFieldStyle(.roundedBorder)
+                    TextField("Plugin does…", text: exampleBinding(example.id, field: .pluginDoes))
+                        .textFieldStyle(.roundedBorder)
+                    if controller.skillDraft.examples.count > 1 {
+                        Button("Remove") { controller.removeExample(id: example.id) }
+                            .font(.caption)
+                    }
+                }
+                .padding(10)
+                .background(Color.primary.opacity(0.04), in: RoundedRectangle(cornerRadius: 8))
+            }
+        }
+    }
+
+    private enum ExampleField { case userSays, pluginDoes }
+
+    private func exampleBinding(_ id: String, field: ExampleField) -> Binding<String> {
+        Binding(
+            get: {
+                guard let index = controller.skillDraft.examples.firstIndex(where: { $0.id == id }) else {
+                    return ""
+                }
+                switch field {
+                case .userSays: return controller.skillDraft.examples[index].userSays
+                case .pluginDoes: return controller.skillDraft.examples[index].pluginDoes
+                }
+            },
+            set: { newValue in
+                switch field {
+                case .userSays: controller.updateExample(id: id, userSays: newValue)
+                case .pluginDoes: controller.updateExample(id: id, pluginDoes: newValue)
+                }
+            }
+        )
+    }
+
+    private func triggerChip(_ trigger: PluginSkillDraft.Trigger) -> some View {
+        let available = controller.skillDraft.isTriggerAvailable(trigger)
+        let on = available && controller.skillDraft.triggers.contains(trigger)
+        return Button {
+            controller.toggleTrigger(trigger)
+        } label: {
+            Text(trigger.label)
+                .font(.caption.weight(.medium))
+                .padding(.horizontal, 10)
+                .padding(.vertical, 6)
+                .background(chipBackground(on: on, available: available))
+                .foregroundStyle(available ? .primary : .tertiary)
+                .clipShape(Capsule())
+        }
+        .buttonStyle(.plain)
+        .disabled(!available)
+        .help(triggerHelp(trigger, available: available))
+    }
+
+    private func chipBackground(on: Bool, available: Bool) -> Color {
+        guard available else { return Color.primary.opacity(0.03) }
+        return on ? Color.accentColor.opacity(0.15) : Color.primary.opacity(0.05)
+    }
+
+    private func triggerHelp(
+        _ trigger: PluginSkillDraft.Trigger,
+        available: Bool
+    ) -> String {
+        guard !available else { return "" }
+        switch controller.skillDraft.plannedKind {
+        case .messagingConnector:
+            switch trigger {
+            case .schedule:
+                return "Connectors respond in Messaging, not on a timer."
+            default:
+                return "Not available for messaging connectors."
+            }
+        case .customCapability:
+            switch trigger {
+            case .messaging:
+                return "Only messaging connectors use the Messaging tab."
+            default:
+                return "Not available for this plugin type."
+            }
+        }
+    }
+
+    private var nameFieldSection: some View {
+        VStack(alignment: .leading, spacing: 6) {
+            Text("Plugin name")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+            TextField("Plugin name", text: controller.skillDraftBinding(\.pluginName))
+                .textFieldStyle(.roundedBorder)
+                .accessibilityIdentifier("connector-plugin-name")
+            if controller.canConfirmPluginName {
+                Text("Invoke this plugin in chat as /\(normalizedPluginID()).")
+                    .font(.caption2)
+                    .foregroundStyle(.tertiary)
+            } else {
+                Text("Use letters, numbers, and hyphens (for example tech-news).")
+                    .font(.caption2)
+                    .foregroundStyle(.orange)
+            }
+        }
+    }
+
+    private func normalizedPluginID() -> String {
+        let trimmed = controller.skillDraft.pluginName.trimmingCharacters(in: .whitespacesAndNewlines)
+        if let normalized = try? PluginID.normalized(trimmed) {
+            return normalized.rawValue
+        }
+        return trimmed.isEmpty ? "plugin" : trimmed
+    }
+
+    private var previewForm: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: 16) {
+                plannedKindBadge
+
+                nameFieldSection
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("Scenarios")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                    ForEach(controller.skillDraft.previewScenarios(), id: \.self) { scenario in
+                        Text(scenario)
+                            .font(.subheadline)
+                            .fixedSize(horizontal: false, vertical: true)
+                    }
+                }
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("Package")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                    ForEach(controller.skillDraft.packageOutline(), id: \.self) { line in
+                        Label(line, systemImage: "doc")
+                            .font(.caption)
+                            .foregroundStyle(.secondary)
+                    }
+                }
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("SKILL.md")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                    Text(controller.skillDraft.skillMarkdown())
+                        .font(.caption.monospaced())
+                        .foregroundStyle(.secondary)
+                        .padding(10)
+                        .frame(maxWidth: .infinity, alignment: .leading)
+                        .background(Color.primary.opacity(0.04), in: RoundedRectangle(cornerRadius: 8))
+                        .textSelection(.enabled)
+                }
+            }
+        }
+    }
+
+    @ViewBuilder
+    private func failureBody(message: String, technicalDetail: String?) -> some View {
+        VStack(alignment: .leading, spacing: 10) {
+            Label("Nothing was installed", systemImage: "minus.circle")
+                .font(.subheadline.weight(.semibold))
+                .foregroundStyle(.secondary)
+            Text("Your sidebar and Messaging are unchanged.")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+            Text(message)
+                .font(.body)
+                .fixedSize(horizontal: false, vertical: true)
+                .padding(.top, 4)
+            if let technicalDetail, !technicalDetail.isEmpty {
+                DisclosureGroup("Technical details") {
+                    Text(technicalDetail)
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                        .fixedSize(horizontal: false, vertical: true)
+                        .textSelection(.enabled)
                 }
-                .buttonStyle(ModalPrimaryButtonStyle())
-                .keyboardShortcut(.defaultAction)
+            }
+        }
+    }
+
+    @ViewBuilder
+    private func successBody(pluginID: String, outcome: PluginCreationController.SuccessOutcome) -> some View {
+        switch outcome {
+        case .plugin:
+            if controller.skillDraft.plannedKind == .messagingConnector {
+                Text("Your connector /\(pluginID) is ready. Open it to start talking in Messaging.")
+                    .font(.body)
+                    .fixedSize(horizontal: false, vertical: true)
+            } else {
+                Text("Your plugin /\(pluginID) is ready.")
+                    .font(.body)
+                    .fixedSize(horizontal: false, vertical: true)
             }
         }
     }
@@ -443,169 +598,47 @@ struct PluginsWorkspaceView: View {
             set: { controller.credentialDrafts[id] = $0 }
         )
     }
+}
 
-    private func typeButton(
-        title: String,
-        subtitle: String,
-        type: PluginFactoryCreateInput.PluginType,
-        enabled: Bool
-    ) -> some View {
-        Button {
-            guard enabled else { return }
-            controller.selectType(type)
-        } label: {
-            HStack(alignment: .top, spacing: 10) {
-                VStack(alignment: .leading, spacing: 4) {
-                    Text(title)
-                        .font(.body.weight(.semibold))
-                        .foregroundStyle(enabled ? .primary : .secondary)
-                    Text(subtitle)
-                        .font(.caption)
-                        .foregroundStyle(.secondary)
-                }
-                Spacer()
-                if !enabled {
-                    Text("Soon")
-                        .font(.caption2)
-                        .foregroundStyle(.secondary)
-                } else if controller.selectedType == type {
-                    Image(systemName: "checkmark.circle.fill")
-                        .foregroundStyle(Color.accentColor)
-                }
-            }
-            .padding(12)
-            .frame(maxWidth: .infinity, alignment: .leading)
-            .background(
-                controller.selectedType == type && enabled
-                    ? Color.accentColor.opacity(0.12)
-                    : Color.primary.opacity(enabled ? 0.05 : 0.03)
+/// Simple horizontal flow for trigger chips when `Layout` is unavailable.
+private struct FlowLayout: Layout {
+    var spacing: CGFloat = 8
+
+    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
+        let result = arrange(proposal: proposal, subviews: subviews)
+        return result.size
+    }
+
+    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) {
+        let result = arrange(proposal: proposal, subviews: subviews)
+        for (index, frame) in result.frames.enumerated() {
+            subviews[index].place(
+                at: CGPoint(x: bounds.minX + frame.minX, y: bounds.minY + frame.minY),
+                proposal: ProposedViewSize(frame.size)
             )
-            .clipShape(RoundedRectangle(cornerRadius: 10))
         }
-        .buttonStyle(.plain)
-        .disabled(!enabled)
     }
 
-    private var newsReaderForm: some View {
-        ScrollView {
-            VStack(alignment: .leading, spacing: 14) {
-                TextField("Name this list", text: $controller.newsName)
-                    .textFieldStyle(.roundedBorder)
-                    .accessibilityIdentifier("news-list-name")
-                Text("Topics")
-                    .font(.caption)
-                    .foregroundStyle(.secondary)
-                LazyVGrid(columns: [GridItem(.adaptive(minimum: 110), spacing: 8)], spacing: 8) {
-                    ForEach(NewsPresetTopic.allCases) { topic in
-                        let on = controller.selectedNewsTopics.contains(topic)
-                        Button {
-                            if on {
-                                controller.selectedNewsTopics.remove(topic)
-                            } else {
-                                controller.selectedNewsTopics.insert(topic)
-                            }
-                        } label: {
-                            Text(topic.displayName)
-                                .font(.caption.weight(.medium))
-                                .frame(maxWidth: .infinity)
-                                .padding(.vertical, 8)
-                                .background(on ? Color.accentColor.opacity(0.15) : Color.primary.opacity(0.05))
-                                .clipShape(RoundedRectangle(cornerRadius: 8))
-                        }
-                        .buttonStyle(.plain)
-                    }
-                }
-                HStack {
-                    TextField("Add a custom topic", text: $controller.newsTopicDraft)
-                        .textFieldStyle(.roundedBorder)
-                        .onSubmit { controller.addNewsTopic() }
-                    Button("Add") { controller.addNewsTopic() }
-                }
-                if !controller.extraNewsTopics.isEmpty {
-                    Text(controller.extraNewsTopics.joined(separator: ", "))
-                        .font(.caption)
-                        .foregroundStyle(.secondary)
-                }
-                Text("Sources")
-                    .font(.caption)
-                    .foregroundStyle(.secondary)
-                LazyVGrid(columns: [GridItem(.adaptive(minimum: 130), spacing: 8)], spacing: 8) {
-                    ForEach(NewsPresetSource.allCases) { source in
-                        let on = controller.selectedNewsSources.contains(source)
-                        Button {
-                            if on {
-                                controller.selectedNewsSources.remove(source)
-                            } else {
-                                controller.selectedNewsSources.insert(source)
-                            }
-                        } label: {
-                            Text(source.source.label)
-                                .font(.caption.weight(.medium))
-                                .frame(maxWidth: .infinity)
-                                .padding(.vertical, 8)
-                                .background(on ? Color.accentColor.opacity(0.15) : Color.primary.opacity(0.05))
-                                .clipShape(RoundedRectangle(cornerRadius: 8))
-                        }
-                        .buttonStyle(.plain)
-                    }
-                }
-                HStack {
-                    TextField("https://…", text: $controller.newsURLDraft)
-                        .textFieldStyle(.roundedBorder)
-                        .accessibilityIdentifier("news-url-field")
-                        .onSubmit { controller.addNewsURL() }
-                    Button("Add URL") { controller.addNewsURL() }
-                }
-                ForEach(controller.extraNewsURLs, id: \.self) { url in
-                    VStack(alignment: .leading, spacing: 2) {
-                        HStack {
-                            Text(url)
-                                .font(.caption)
-                                .lineLimit(1)
-                            Spacer()
-                            Button("Remove") { controller.removeNewsURL(url) }
-                                .font(.caption)
-                        }
-                        if let reason = newsURLPaywallReason(url) {
-                            Text(reason)
-                                .font(.caption2)
-                                .foregroundStyle(.orange)
-                        }
-                    }
-                }
-                HStack(alignment: .top, spacing: 8) {
-                    Image(systemName: "exclamationmark.triangle.fill")
-                        .foregroundStyle(.orange)
-                    Text(NewsPaywall.userWarning)
-                        .fixedSize(horizontal: false, vertical: true)
-                }
-                .font(.caption)
-                .padding(10)
-                .frame(maxWidth: .infinity, alignment: .leading)
-                .background(Color.orange.opacity(0.12), in: RoundedRectangle(cornerRadius: 8))
-                .accessibilityElement(children: .combine)
-                .accessibilityIdentifier("news-paywall-warning")
-                Picker("Mode", selection: $controller.newsMode) {
-                    ForEach(NewsReaderMode.allCases, id: \.self) { mode in
-                        Text(mode.displayName).tag(mode)
-                    }
-                }
-                Stepper("Up to \(controller.newsMaxCount) items", value: $controller.newsMaxCount, in: 5...50, step: 5)
-                Picker("Schedule", selection: $controller.newsSchedule) {
-                    ForEach(NewsReaderSchedule.allCases, id: \.self) { schedule in
-                        Text(schedule.displayName).tag(schedule)
-                    }
-                }
+    private func arrange(proposal: ProposedViewSize, subviews: Subviews) -> (size: CGSize, frames: [CGRect]) {
+        let maxWidth = proposal.width ?? .infinity
+        var x: CGFloat = 0
+        var y: CGFloat = 0
+        var rowHeight: CGFloat = 0
+        var frames: [CGRect] = []
+
+        for subview in subviews {
+            let size = subview.sizeThatFits(.unspecified)
+            if x + size.width > maxWidth, x > 0 {
+                x = 0
+                y += rowHeight + spacing
+                rowHeight = 0
             }
+            frames.append(CGRect(x: x, y: y, width: size.width, height: size.height))
+            rowHeight = max(rowHeight, size.height)
+            x += size.width + spacing
         }
-    }
 
-    private func newsURLPaywallReason(_ raw: String) -> String? {
-        let trimmed = raw.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !trimmed.isEmpty else { return nil }
-        let normalized = trimmed.contains("://") ? trimmed : "https://\(trimmed)"
-        guard let url = URL(string: normalized) else { return nil }
-        return NewsPaywall.preflightRejection(url: url)
+        return (CGSize(width: maxWidth, height: y + rowHeight), frames)
     }
 }
 
diff --git a/ui/ui/Services/AgentServiceClient.swift b/ui/ui/Services/AgentServiceClient.swift
index 339fb52d..73b1afd8 100644
--- a/ui/ui/Services/AgentServiceClient.swift
+++ b/ui/ui/Services/AgentServiceClient.swift
@@ -74,7 +74,10 @@ public final class AgentServiceClient: @unchecked Sendable {
 
     /// Connect (launch-on-demand), bootstrap DB/logs, return health. Retries a few times.
     /// Use at app startup (and when `ensureReadyForTurn` finds the link dead).
-    public func ensureUpAndHealth(retries: Int = 3) async throws -> ServiceHealthReport {
+    public func ensureUpAndHealth(
+        retries: Int = 3,
+        verifyHealth: Bool = true
+    ) async throws -> ServiceHealthReport {
         var lastError: Error?
         for attempt in 0..<max(1, retries) {
             do {
@@ -91,13 +94,26 @@ public final class AgentServiceClient: @unchecked Sendable {
                     throw AgentServiceClientError.bootstrapFailed(boot.message)
                 }
 
-                let report: ServiceHealthReport = try await invoke(timeout: callTimeoutNanoseconds) {
-                    try await self.requestHealth(using: proxy)
-                }
-                await MainActor.run {
-                    debugLog(
-                        "AgentService health: status=\(report.status.rawValue) pid=\(report.pid) detail=\(report.detail ?? "")"
+                let report: ServiceHealthReport
+                if verifyHealth {
+                    report = try await invoke(timeout: callTimeoutNanoseconds) {
+                        try await self.requestHealth(using: proxy)
+                    }
+                    await MainActor.run {
+                        debugLog(
+                            "AgentService health: status=\(report.status.rawValue) pid=\(report.pid) detail=\(report.detail ?? "")"
+                        )
+                    }
+                } else {
+                    report = ServiceHealthReport(
+                        service: .daemon,
+                        status: .ok,
+                        detail: nil,
+                        guestRuntimeImage: DerrickGuestRuntime.guestDockerImage
                     )
+                    await MainActor.run {
+                        debugLog("AgentService ensure-up: bootstrap ok (health check skipped at startup)")
+                    }
                 }
                 markReady()
                 return report
diff --git a/ui/ui/Views/ContentView.swift b/ui/ui/Views/ContentView.swift
index 34845a8d..46013e34 100644
--- a/ui/ui/Views/ContentView.swift
+++ b/ui/ui/Views/ContentView.swift
@@ -234,7 +234,6 @@ struct ContentView: View {
     @ObservedObject private var bootstrapStatus = AppBootstrapStatus.shared
     @StateObject private var chatSessions = ChatSessionStore()
     @StateObject private var messaging = MessagingStore()
-    @ObservedObject private var news = NewsReaderStore.shared
     @State private var workspace: AppWorkspace = .chats
 
     private var secretStore: SecretStore {
@@ -275,10 +274,7 @@ struct ContentView: View {
     }
 
     private var currentHelperAPIKey: String? {
-        secretResolver.resolve(
-            account: selectedProvider.secretAccount,
-            environmentKeys: selectedProvider.apiKeyEnvironmentKeys
-        )
+        LLMProviderCredentialGate.resolveAPIKey(for: selectedProvider, resolver: secretResolver)
     }
 
     private var currentHelperReviewerModelJSON: String? {
@@ -392,7 +388,6 @@ struct ContentView: View {
                     modelThinkingSettings: modelThinkingSettings ?? LLMModelThinkingSettings(repository: helperModelSettings.settingsRepository),
                     chatSessions: chatSessions,
                     messaging: messaging,
-                    news: news,
                     workspace: $workspace,
                     isDebugEnabled: isDebugEnabled
                 )
@@ -406,14 +401,12 @@ struct ContentView: View {
             VStack(spacing: 0) {
                 if workspace == .messaging {
                     MessagingTabBarView(store: messaging)
-                } else if workspace != .debugLogs && workspace != .plugins && workspace != .news {
+                } else if workspace != .debugLogs && workspace != .plugins {
                     ChatTabBarView(store: chatSessions)
                 }
                 switch workspace {
                 case .messaging:
                     MessagingConversationView(store: messaging)
-                case .news:
-                    NewsWorkspaceView(store: news)
                 case .debugLogs:
                     DebugLogsView(repository: repository)
                 case .plugins:
@@ -431,13 +424,6 @@ struct ContentView: View {
                                 }
                                 Task { await pluginFactoryList.reload() }
                             }
-                        },
-                        onOpenNewsReader: { readerID in
-                            Task { @MainActor in
-                                workspace = .news
-                                await news.select(id: readerID)
-                                pluginCreationController.dismissSuccess()
-                            }
                         }
                     )
                 default:
@@ -599,7 +585,7 @@ struct ContentView: View {
             minWidth: 380,
             minHeight: 0,
             maxWidth: 440,
-            maxHeight: bootstrapStatus.phase == .failed ? 420 : 280,
+            maxHeight: bootstrapModalMaxHeight,
             onBackdropDismiss: bootstrapStatus.phase == .failed
                 ? { bootstrapStatus.dismissFailure() }
                 : nil,
@@ -608,10 +594,7 @@ struct ContentView: View {
                 : nil,
             header: {
                 HStack(spacing: 10) {
-                    if bootstrapStatus.showsProgressIndicator {
-                        ProgressView()
-                            .controlSize(.small)
-                    } else if bootstrapStatus.phase == .failed {
+                    if bootstrapStatus.phase == .failed {
                         Image(systemName: ModalChrome.bootstrapFailureSymbol)
                             .font(ModalChrome.symbolFont)
                             .symbolRenderingMode(.hierarchical)
@@ -629,23 +612,29 @@ struct ContentView: View {
             },
             body: {
                 VStack(alignment: .leading, spacing: 12) {
-                    Text(bootstrapStatus.statusMessage)
-                        .font(.body)
-                        .foregroundStyle(.primary)
-                        .fixedSize(horizontal: false, vertical: true)
-
-                    if bootstrapStatus.phase == .failed, let detail = bootstrapStatus.failureMessage,
-                       detail != bootstrapStatus.statusMessage {
-                        Text(detail)
-                            .font(.subheadline)
-                            .foregroundStyle(.secondary)
-                            .fixedSize(horizontal: false, vertical: true)
+                    if bootstrapStatus.isInitializing {
+                        VStack(alignment: .leading, spacing: 10) {
+                            ForEach(bootstrapStatus.activeLoadingTasks) { task in
+                                HStack(alignment: .top, spacing: 10) {
+                                    ProgressView()
+                                        .controlSize(.small)
+                                        .frame(width: 16, height: 16)
+                                        .padding(.top, 2)
+                                    Text(task.message)
+                                        .font(.body)
+                                        .foregroundStyle(.primary)
+                                        .fixedSize(horizontal: false, vertical: true)
+                                }
+                            }
+                        }
+                        .animation(.easeOut(duration: 0.2), value: bootstrapStatus.activeLoadingTasks)
                     }
 
-                    if bootstrapStatus.isInitializing {
-                        Text(bootstrapProgressHint)
-                            .font(.caption)
-                            .foregroundStyle(.secondary)
+                    if bootstrapStatus.phase == .failed {
+                        Text(bootstrapStatus.failureMessage ?? bootstrapStatus.statusMessage)
+                            .font(.body)
+                            .foregroundStyle(.primary)
+                            .fixedSize(horizontal: false, vertical: true)
                     }
                 }
                 .padding(.horizontal, 20)
@@ -723,17 +712,12 @@ struct ContentView: View {
         .background(WindowConfigurator())
     }
 
-    private var bootstrapProgressHint: String {
-        switch bootstrapStatus.phase {
-        case .preparingImage, .checkingDocker, .verifyingEnvironment:
-            return "First launch may download a Docker image. Keep Docker Desktop running."
-        case .connectingHelper:
-            return "Starting the background helper…"
-        case .loadingSession:
-            return "Loading your local workspace…"
-        default:
-            return "Starting…"
+    private var bootstrapModalMaxHeight: CGFloat {
+        if bootstrapStatus.phase == .failed {
+            return 420
         }
+        let rowCount = max(bootstrapStatus.activeLoadingTasks.count, 1)
+        return CGFloat(120 + rowCount * 34)
     }
 
     @MainActor
@@ -764,32 +748,40 @@ struct ContentView: View {
 
             do {
                 bootstrapStatus.update(phase: .loadingSession, message: "Starting Derrick…")
+                bootstrapStatus.beginTask(.daemon)
+                bootstrapStatus.beginTask(.database)
+                bootstrapStatus.beginTask(.docker)
 
-                // Prewarm Docker in parallel, but connect daemon + DB first so the modal
-                // does not sit on "Guest runtime ready" while XPC bootstrap is still retrying.
-                async let dockerPeer = prewarmLaunchDockerPeer()
+                // Docker reachability, daemon, and DB are independent — run in parallel.
+                let dockerPeerTask = Task { try await prewarmLaunchDockerPeer() }
+                async let health = connectLaunchDaemon()
+                async let repo = loadLaunchRepository()
 
-                let health = try await connectLaunchDaemon()
+                let healthResult = try await health
+                bootstrapStatus.completeTask(.daemon)
                 debugLog(
-                    "Daemon ensure-up ok status=\(health.status.rawValue) pid=\(health.pid) runtime=\(health.guestRuntimeImage ?? "?") detail=\(health.detail ?? "")"
+                    "Daemon ensure-up ok status=\(healthResult.status.rawValue) pid=\(healthResult.pid) runtime=\(healthResult.guestRuntimeImage ?? "?") detail=\(healthResult.detail ?? "")"
                 )
 
-                let repo = try await loadLaunchRepository()
-
-                if let peer = try await dockerPeer {
-                    do {
-                        try await AgentServiceClient.shared.setDockerHelperPeerEndpoint(peer)
-                        debugLog("Docker helper peer endpoint handed to daemon MCP")
-                    } catch {
-                        debugLog("Docker helper peer handoff skipped: \(error.localizedDescription)")
-                    }
-                }
+                let repoResult = try await repo
+                bootstrapStatus.completeTask(.database)
 
                 sessionReady = true
                 bootstrapStatus.markReady()
-                await chatSessions.configure(repository: repo)
-                await messaging.configure(repository: repo)
-                await DerrickNotificationService.shared.activateSession(repository: repo)
+                await chatSessions.configure(repository: repoResult)
+                await messaging.configure(repository: repoResult)
+                await DerrickNotificationService.shared.activateSession(repository: repoResult)
+
+                Task {
+                    if let peer = try? await dockerPeerTask.value {
+                        do {
+                            try await AgentServiceClient.shared.setDockerHelperPeerEndpoint(peer)
+                            debugLog("Docker helper peer endpoint handed to daemon MCP")
+                        } catch {
+                            debugLog("Docker helper peer handoff skipped: \(error.localizedDescription)")
+                        }
+                    }
+                }
                 if isDebugEnabled {
                     debugLogStore.log("UI client ready (Docker + derrickd Agent/Job/MCP)")
                 }
@@ -824,7 +816,7 @@ struct ContentView: View {
         bootstrapStatus.update(phase: .connectingHelper, message: "Connecting to Derrick daemon…")
         try? await JobServiceLoginAgent.ensureRegistered()
         JobServiceLoginAgent.ensureHelperProcessRunning()
-        return try await AgentServiceClient.shared.ensureUpAndHealth(retries: 8)
+        return try await AgentServiceClient.shared.ensureUpAndHealth(retries: 4, verifyHealth: false)
     }
 
     @MainActor
@@ -838,13 +830,11 @@ struct ContentView: View {
     @MainActor
     private func configureClientRepositoryServices(repository: DBRepository) async {
         await ServiceLogRecorder.shared.configure(repository: repository)
-        await EgressAllowlistService.shared.configure(repository: repository)
         await ContentSensitivityGrantService.shared.configure(repository: repository)
         await UsageLimitsService.shared.configure(repository: repository)
         await ContainerLifecycleSettingsService.shared.configure(repository: repository)
         await OrchestrationLimitsSettingsService.shared.configure(repository: repository)
         await PluginFactoryListStore.shared.configure(repository: repository)
-        await NewsReaderStore.shared.configure(repository: repository)
         await AgentProfileStore.shared.configure(repository: repository)
         pluginCreationController.configure(repository: repository)
     }
@@ -852,9 +842,10 @@ struct ContentView: View {
     /// Prewarm Docker in parallel with daemon + DB. Only peer handoff needs both daemon XPC and Docker.
     @MainActor
     private func prewarmLaunchDockerPeer() async throws -> NSXPCListenerEndpoint? {
-        bootstrapStatus.update(phase: .checkingDocker, message: "Starting Docker runtime…")
+        bootstrapStatus.updateTask(.docker, message: "Starting Docker runtime…")
         _ = XPCDockerRunner.shared
-        try await XPCDockerRunner.shared.waitUntilPrewarmed()
+        try await XPCDockerRunner.shared.waitUntilDockerReachable()
+        bootstrapStatus.completeTask(.docker)
         do {
             return try await XPCDockerRunner.shared.fetchPeerListenerEndpoint()
         } catch {
@@ -1489,10 +1480,7 @@ struct ContentView: View {
     }
 
     private func resolveAPIKey() -> String? {
-        secretResolver.resolve(
-            account: selectedModel.provider.secretAccount,
-            environmentKeys: selectedModel.provider.apiKeyEnvironmentKeys
-        )
+        LLMProviderCredentialGate.resolveAPIKey(for: selectedModel.provider, resolver: secretResolver)
     }
 
     @ViewBuilder
diff --git a/ui/ui/Views/LLMModelSettingsView.swift b/ui/ui/Views/LLMModelSettingsView.swift
index 2321a609..d3209fc9 100644
--- a/ui/ui/Views/LLMModelSettingsView.swift
+++ b/ui/ui/Views/LLMModelSettingsView.swift
@@ -349,7 +349,7 @@ struct LLMModelSettingsView: View {
             Text("Multi-agent")
                 .font(.system(size: 26, weight: .semibold, design: .rounded))
 
-            Text("Caps for agents_spawn and worker turns in a chat session. New tabs use saved values; open tabs keep the limits they started with. Parallel script_exec runs wait in line (one Python guest container at a time). Crawls and file conversions have their own lines.")
+            Text("Caps for agents_spawn and worker turns in a chat session. New tabs use saved values; open tabs keep the limits they started with. Parallel script_exec runs wait in line (one Go guest container at a time). Crawls and file conversions have their own lines.")
                 .font(.subheadline)
                 .foregroundStyle(.secondary)
                 .fixedSize(horizontal: false, vertical: true)
diff --git a/ui/ui/Views/MarkdownView.swift b/ui/ui/Views/MarkdownView.swift
index d39b0670..c5b9f787 100644
--- a/ui/ui/Views/MarkdownView.swift
+++ b/ui/ui/Views/MarkdownView.swift
@@ -2,6 +2,7 @@ import AppKit
 import SwiftUI
 
 enum MarkdownBlock: Identifiable {
+    case heading(level: Int, text: String)
     case paragraph(String)
     case bullet(String)
     case numbered(number: Int, text: String)
@@ -10,6 +11,8 @@ enum MarkdownBlock: Identifiable {
 
     var id: String {
         switch self {
+        case .heading(let level, let text):
+            return "h\(level)-\(text.hashValue)"
         case .paragraph(let text):
             return "p-\(text.hashValue)"
         case .bullet(let text):
@@ -66,6 +69,22 @@ enum MarkdownBlock: Identifiable {
                 continue
             }
 
+            if trimmed.hasPrefix("#") {
+                var level = 0
+                var index = trimmed.startIndex
+                while index < trimmed.endIndex, trimmed[index] == "#", level < 6 {
+                    level += 1
+                    index = trimmed.index(after: index)
+                }
+                if level > 0, index < trimmed.endIndex, trimmed[index] == " " {
+                    flushParagraph()
+                    let headingText = String(trimmed[trimmed.index(after: index)...])
+                        .trimmingCharacters(in: .whitespaces)
+                    blocks.append(.heading(level: level, text: headingText))
+                    continue
+                }
+            }
+
             // Check bullet
             if trimmed.hasPrefix("- ") || trimmed.hasPrefix("* ") {
                 flushParagraph()
@@ -290,6 +309,13 @@ struct MarkdownResponseView: View {
     @ViewBuilder
     private func blockView(for block: MarkdownBlock) -> some View {
         switch block {
+        case .heading(let level, let text):
+            Text((try? AttributedString(markdown: text)) ?? AttributedString(text))
+                .font(headingFont(level: level))
+                .fontWeight(.semibold)
+                .padding(.horizontal, 2)
+                .frame(maxWidth: .infinity, alignment: .leading)
+                .textSelection(.enabled)
         case .paragraph(let text):
             Text((try? AttributedString(markdown: text)) ?? AttributedString(text))
                 .lineSpacing(2)
@@ -352,6 +378,16 @@ struct MarkdownResponseView: View {
         }
     }
 
+    private func headingFont(level: Int) -> Font {
+        switch level {
+        case 1: return .title
+        case 2: return .title2
+        case 3: return .title3
+        case 4: return .headline
+        default: return .subheadline
+        }
+    }
+
     @ViewBuilder
     private func csvTableView(table: CSVTable, source: String) -> some View {
         VStack(alignment: .leading, spacing: 10) {
diff --git a/ui/ui/Views/PluginHTMLResultExtractor.swift b/ui/ui/Views/PluginHTMLResultExtractor.swift
index 77e7d828..cbe041a7 100644
--- a/ui/ui/Views/PluginHTMLResultExtractor.swift
+++ b/ui/ui/Views/PluginHTMLResultExtractor.swift
@@ -57,6 +57,7 @@ enum PluginResultExtractor {
                 let format = envelope.payload["format"]?.stringValue?.lowercased()
                 let candidate = envelope.payload["content"]?.stringValue
                     ?? envelope.payload["summary"]?.stringValue
+                    ?? envelope.payload["markdown"]?.stringValue
                     ?? envelope.payload["text"]?.stringValue
                     ?? ""
                 guard !candidate.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
@@ -320,6 +321,7 @@ enum PluginResultExtractor {
 
                 let candidate = item["content"] as? String
                     ?? item["summary"] as? String
+                    ?? item["markdown"] as? String
                     ?? item["text"] as? String
                     ?? ""
                 guard !candidate.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
diff --git a/ui/ui/Views/SidebarView.swift b/ui/ui/Views/SidebarView.swift
index 20b340f4..b719f13d 100644
--- a/ui/ui/Views/SidebarView.swift
+++ b/ui/ui/Views/SidebarView.swift
@@ -10,7 +10,6 @@ struct SidebarView: View {
     @ObservedObject var modelThinkingSettings: LLMModelThinkingSettings
     @ObservedObject var chatSessions: ChatSessionStore
     @ObservedObject var messaging: MessagingStore
-    @ObservedObject var news: NewsReaderStore
     @Binding var workspace: AppWorkspace
     var isDebugEnabled: Bool = false
     /// Reference type must not be recreated every `View` value; hold via `@State`.
@@ -81,17 +80,6 @@ struct SidebarView: View {
                     workspace = .messaging
                     Task { await messaging.syncConnectorsFromFactory() }
                 }
-                SidebarActionRow(
-                    row: SidebarRow(
-                        id: "news",
-                        icon: "newspaper.fill",
-                        title: "News",
-                        isProminent: workspace == .news
-                    )
-                ) {
-                    workspace = .news
-                    Task { await news.reload() }
-                }
                 if isDebugEnabled {
                     SidebarActionRow(
                         row: SidebarRow(
@@ -110,8 +98,6 @@ struct SidebarView: View {
                 pluginsList
             } else if workspace == .messaging {
                 messagingList
-            } else if workspace == .news {
-                newsList
             } else if workspace == .debugLogs {
                 debugLogsHint
             } else {
@@ -289,46 +275,6 @@ struct SidebarView: View {
         }
     }
 
-    private var newsList: some View {
-        VStack(alignment: .leading, spacing: 8) {
-            HStack {
-                Text("Saved lists")
-                    .font(.caption)
-                    .foregroundStyle(.secondary)
-                Spacer()
-            }
-            .padding(.top, 4)
-            ScrollView {
-                LazyVStack(alignment: .leading, spacing: 10) {
-                    if news.readers.isEmpty {
-                        Text("No news lists yet")
-                            .font(.system(size: sideMenuRecentsFontSize))
-                            .foregroundStyle(.secondary)
-                    } else {
-                        ForEach(news.readers) { reader in
-                            Button {
-                                workspace = .news
-                                Task { await news.select(id: reader.id) }
-                            } label: {
-                                Text(reader.name)
-                                    .font(.system(size: sideMenuRecentsFontSize))
-                                    .lineLimit(1)
-                                    .frame(maxWidth: .infinity, alignment: .leading)
-                                    .foregroundStyle(
-                                        news.selectedReaderID == reader.id
-                                            ? Color.primary
-                                            : Color.primary.opacity(0.9)
-                                    )
-                            }
-                            .buttonStyle(.plain)
-                        }
-                    }
-                }
-                .frame(maxWidth: .infinity, alignment: .leading)
-            }
-        }
-    }
-
     private var pluginsList: some View {
         VStack(alignment: .leading, spacing: 8) {
             ScrollView {
@@ -439,7 +385,6 @@ struct SidebarView: View {
         modelThinkingSettings: LLMModelThinkingSettings(repository: repo),
         chatSessions: store,
         messaging: MessagingStore(),
-        news: NewsReaderStore.shared,
         workspace: .constant(.chats)
     )
 }
diff --git a/ui/uiTests/AppBootstrapStatusTests.swift b/ui/uiTests/AppBootstrapStatusTests.swift
index 7fd7994e..007d27a1 100644
--- a/ui/uiTests/AppBootstrapStatusTests.swift
+++ b/ui/uiTests/AppBootstrapStatusTests.swift
@@ -174,6 +174,45 @@ import Testing
         #expect(status.phase == .ready)
     }
 
+    @MainActor
+    @Test func loadingSessionDoesNotOverwriteConnectingHelper() {
+        let status = freshStatus()
+        #expect(status.beginLoadingSession())
+        status.update(phase: .connectingHelper, message: "Connecting to Derrick daemon…")
+        status.update(phase: .loadingSession, message: "Opening local database…")
+        #expect(status.phase == .connectingHelper)
+        #expect(status.statusMessage == "Connecting to Derrick daemon…")
+    }
+
+    @MainActor
+    @Test func parallelLoadingTasksTrackIndependently() {
+        let status = freshStatus()
+        #expect(status.beginLoadingSession())
+        status.beginTask(.daemon)
+        status.beginTask(.database)
+        status.beginTask(.docker)
+        #expect(status.activeLoadingTasks.map(\.id) == [.daemon, .database, .docker])
+        status.completeTask(.database)
+        #expect(status.activeLoadingTasks.map(\.id) == [.daemon, .docker])
+        status.completeTask(.daemon)
+        status.completeTask(.docker)
+        #expect(status.activeLoadingTasks.isEmpty)
+    }
+
+    @MainActor
+    @Test func phaseUpdateAddsMatchingLoadingTasks() {
+        let status = freshStatus()
+        #expect(status.beginLoadingSession())
+        status.update(phase: .connectingHelper, message: "Connecting to Derrick daemon…")
+        status.update(phase: .loadingSession, message: "Opening local database…")
+        status.update(phase: .checkingDocker, message: "Checking Docker Desktop…")
+        #expect(status.activeLoadingTasks.map(\.id) == [.daemon, .database, .docker])
+        status.update(phase: .preparingImage, message: "Preparing worker image…")
+        #expect(status.activeLoadingTasks.map(\.id) == [.daemon, .database, .docker, .workerImage])
+        status.update(phase: .verifyingEnvironment, message: "Worker image ready.")
+        #expect(status.activeLoadingTasks.map(\.id) == [.daemon, .database, .docker])
+    }
+
     @MainActor
     @Test func cancelClearsInProgressModal() {
         let status = freshStatus()
diff --git a/ui/uiTests/MessagingNavigationTests.swift b/ui/uiTests/MessagingNavigationTests.swift
index 426c103e..88476aea 100644
--- a/ui/uiTests/MessagingNavigationTests.swift
+++ b/ui/uiTests/MessagingNavigationTests.swift
@@ -343,9 +343,9 @@ import Testing
         _ = try await repository.createEmptyDatabaseIfNeeded(username: "ui", password: "ui")
         let manifestJSON = """
         {"$schema":"\(PluginContract.agentPluginSchema)","name":"slack-bot","version":"1.0.0",\
-        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.py","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
+        "extensions":{"app.derrick":{"entrypoint":"./app.derrick/plugin.go","role":"connector","messaging_ops":["sync_threads","poll_inbox","send_message"]}}}
         """
-        let runtimeJSON = #"{"language":"python","entrypoint":"./app.derrick/plugin.py"}"#
+        let runtimeJSON = #"{"language":"go","entrypoint":"./app.derrick/plugin.go"}"#
         let guestSource = "print([])"
         var release = PluginFactoryRelease(
             pluginID: "slack-bot",
diff --git a/ui/uiTests/PromptResourcesTests.swift b/ui/uiTests/PromptResourcesTests.swift
index 66950af9..0c9990a0 100644
--- a/ui/uiTests/PromptResourcesTests.swift
+++ b/ui/uiTests/PromptResourcesTests.swift
@@ -74,10 +74,10 @@ import Testing
 
     @Test func loadsGuestSDKFromResourcesDirectory() throws {
         let source = try PromptResources.guestSDKSource()
-        #expect(source.contains("standalone Python script"))
+        #expect(source.contains("package main"))
         let wrapped = try PromptResources.guestSDKForModel()
-        #expect(wrapped.contains("```python"))
-        #expect(wrapped.contains("Python guest contract"))
+        #expect(wrapped.contains("```go"))
+        #expect(wrapped.contains("script-exec-contract.json"))
     }
 
     @Test func throwsWhenConversationRAGInstructionsAreMissing() throws {
diff --git a/ui/uiTests/uiTests.swift b/ui/uiTests/uiTests.swift
index c2687c8d..a3f64c31 100644
--- a/ui/uiTests/uiTests.swift
+++ b/ui/uiTests/uiTests.swift
@@ -205,6 +205,8 @@ import DBRepository
         #expect(LLMProviderCredentialGate.hasAPIKey(for: .openai, resolver: resolver))
         #expect(!LLMProviderCredentialGate.hasAPIKey(for: .google, resolver: resolver))
         #expect(LLMProviderCredentialGate.configuredProviders(resolver: resolver) == [.openai])
+        #expect(LLMProviderCredentialGate.resolveAPIKey(for: .openai, resolver: resolver) == "test")
+        #expect(LLMProviderCredentialGate.resolveAPIKey(for: .google, resolver: resolver) == nil)
     }
 
     @Test func llmFailureClassifierDetectsCreditErrors() {
diff --git a/workers/go/cmd/derrick-crawler/main.go b/workers/go/cmd/derrick-crawler/main.go
new file mode 100644
index 00000000..4ea3160b
--- /dev/null
+++ b/workers/go/cmd/derrick-crawler/main.go
@@ -0,0 +1,103 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"io"
+	"os"
+	"strconv"
+
+	"github.com/jsoneaday/derrick/workers/internal/contract"
+	"github.com/jsoneaday/derrick/workers/internal/crawler"
+)
+
+func main() {
+	input, err := io.ReadAll(os.Stdin)
+	if err != nil {
+		writeResult(blockedResult("", "Crawler input must be a valid JSON object."))
+		return
+	}
+
+	var req crawler.Request
+	if err := json.Unmarshal(input, &req); err != nil {
+		writeResult(blockedResult("", "Crawler input must be a valid JSON object."))
+		return
+	}
+
+	validated, err := crawler.Validate(req)
+	if err != nil {
+		writeResult(blockedResult(req.StartURL, err.Error()))
+		return
+	}
+
+	proxy := readProxy()
+	ctx := context.Background()
+	result := crawler.Run(ctx, validated, proxy)
+	if len(result.Pages) == 0 && result.StopReason == crawler.StopCompleted {
+		result.OK = false
+	}
+	if len(result.Pages) > 0 {
+		result.OK = true
+	}
+	writeResult(result)
+}
+
+func readProxy() *crawler.ProxyConfig {
+	host := os.Getenv("DERRICK_EGRESS_PROXY_HOST")
+	portStr := os.Getenv("DERRICK_EGRESS_PROXY_PORT")
+	token := os.Getenv("DERRICK_EGRESS_PROXY_TOKEN")
+	if host == "" && portStr == "" && token == "" {
+		return nil
+	}
+	port, _ := strconv.Atoi(portStr)
+	return &crawler.ProxyConfig{Host: host, Port: port, Token: token}
+}
+
+func blockedResult(startURL string, message string) crawler.Result {
+	return crawler.Result{
+		OK:         false,
+		StartURL:   startURL,
+		Pages:      []crawler.Page{},
+		StopReason: crawler.StopBlocked,
+		Diagnostics: []string{message},
+	}
+}
+
+func writeResult(result crawler.Result) {
+	payload, err := encodedCrawlerResult(result)
+	if err != nil {
+		writeEncodedResult(blockedResult(result.StartURL, "Crawler output violated worker contract."))
+		return
+	}
+	_, _ = os.Stdout.Write(payload)
+}
+
+func encodedCrawlerResult(result crawler.Result) ([]byte, error) {
+	if result.Pages == nil {
+		result.Pages = []crawler.Page{}
+	}
+	if result.Diagnostics == nil {
+		result.Diagnostics = []string{}
+	}
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	enc.SetEscapeHTML(false)
+	if err := enc.Encode(result); err != nil {
+		return nil, err
+	}
+	data := bytes.TrimSpace(buf.Bytes())
+	if err := contract.ValidateWebCrawlerResultJSON(data); err != nil {
+		return nil, err
+	}
+	return append(data, '\n'), nil
+}
+
+func writeEncodedResult(result crawler.Result) {
+	payload, err := encodedCrawlerResult(result)
+	if err != nil {
+		fallback := blockedResult("", "Crawler failed to produce schema-compliant output.")
+		payload, _ = encodedCrawlerResult(fallback)
+	}
+	_, _ = os.Stdout.Write(payload)
+}
diff --git a/workers/go/cmd/derrick-file-extractor/main.go b/workers/go/cmd/derrick-file-extractor/main.go
new file mode 100644
index 00000000..8a93b092
--- /dev/null
+++ b/workers/go/cmd/derrick-file-extractor/main.go
@@ -0,0 +1,77 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"os"
+
+	"github.com/jsoneaday/derrick/workers/internal/contract"
+	"github.com/jsoneaday/derrick/workers/internal/extractor"
+)
+
+func main() {
+	input, err := io.ReadAll(os.Stdin)
+	if err != nil {
+		writeResult(extractor.Result{
+			OK:          false,
+			Operation:   extractor.OperationExtract,
+			Files:       []extractor.FileResult{},
+			Diagnostics: []string{"File extractor input must be a valid JSON object."},
+		}, 1)
+		return
+	}
+
+	var req extractor.Request
+	if err := json.Unmarshal(input, &req); err != nil {
+		writeResult(extractor.Result{
+			OK:          false,
+			Operation:   extractor.OperationExtract,
+			Files:       []extractor.FileResult{},
+			Diagnostics: []string{"File extractor input must be a valid JSON object."},
+		}, 1)
+		return
+	}
+
+	result := extractor.Run(req, extractor.InputDirectory, extractor.OutputDirectory)
+	code := 0
+	if !result.OK {
+		code = 1
+	}
+	writeResult(result, code)
+}
+
+func writeResult(result extractor.Result, code int) {
+	payload, err := encodedExtractorResult(result)
+	if err != nil {
+		payload, _ = encodedExtractorResult(extractor.Result{
+			OK:          false,
+			Operation:   result.Operation,
+			Files:       []extractor.FileResult{},
+			Diagnostics: []string{"File extractor output violated worker contract."},
+		})
+		code = 1
+	}
+	_, _ = os.Stdout.Write(payload)
+	os.Exit(code)
+}
+
+func encodedExtractorResult(result extractor.Result) ([]byte, error) {
+	if result.Files == nil {
+		result.Files = []extractor.FileResult{}
+	}
+	if result.Diagnostics == nil {
+		result.Diagnostics = []string{}
+	}
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	enc.SetEscapeHTML(false)
+	if err := enc.Encode(result); err != nil {
+		return nil, err
+	}
+	data := bytes.TrimSpace(buf.Bytes())
+	if err := contract.ValidateFileExtractorResultJSON(data); err != nil {
+		return nil, err
+	}
+	return append(data, '\n'), nil
+}
diff --git a/workers/go/go.mod b/workers/go/go.mod
new file mode 100644
index 00000000..df29702d
--- /dev/null
+++ b/workers/go/go.mod
@@ -0,0 +1,21 @@
+module github.com/jsoneaday/derrick/workers
+
+go 1.27.1
+
+require (
+	github.com/PuerkitoBio/goquery v1.10.3
+	github.com/xuri/excelize/v2 v2.9.1
+)
+
+require (
+	github.com/andybalholm/cascadia v1.3.3 // indirect
+	github.com/richardlehane/mscfb v1.0.4 // indirect
+	github.com/richardlehane/msoleps v1.0.4 // indirect
+	github.com/santhosh-tekuri/jsonschema/v6 v6.0.3 // indirect
+	github.com/tiendc/go-deepcopy v1.6.0 // indirect
+	github.com/xuri/efp v0.0.1 // indirect
+	github.com/xuri/nfp v0.0.1 // indirect
+	golang.org/x/crypto v0.38.0 // indirect
+	golang.org/x/net v0.40.0 // indirect
+	golang.org/x/text v0.25.0 // indirect
+)
diff --git a/workers/go/go.sum b/workers/go/go.sum
new file mode 100644
index 00000000..80c00844
--- /dev/null
+++ b/workers/go/go.sum
@@ -0,0 +1,100 @@
+github.com/PuerkitoBio/goquery v1.10.3 h1:pFYcNSqHxBD06Fpj/KsbStFRsgRATgnf3LeXiUkhzPo=
+github.com/PuerkitoBio/goquery v1.10.3/go.mod h1:tMUX0zDMHXYlAQk6p35XxQMqMweEKB7iK7iLNd4RH4Y=
+github.com/andybalholm/cascadia v1.3.3 h1:AG2YHrzJIm4BZ19iwJ/DAua6Btl3IwJX+VI4kktS1LM=
+github.com/andybalholm/cascadia v1.3.3/go.mod h1:xNd9bqTn98Ln4DwST8/nG+H0yuB8Hmgu1YHNnWw0GeA=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/richardlehane/mscfb v1.0.4 h1:WULscsljNPConisD5hR0+OyZjwK46Pfyr6mPu5ZawpM=
+github.com/richardlehane/mscfb v1.0.4/go.mod h1:YzVpcZg9czvAuhk9T+a3avCpcFPMUWm7gK3DypaEsUk=
+github.com/richardlehane/msoleps v1.0.1/go.mod h1:BWev5JBpU9Ko2WAgmZEuiz4/u3ZYTKbjLycmwiWUfWg=
+github.com/richardlehane/msoleps v1.0.4 h1:WuESlvhX3gH2IHcd8UqyCuFY5yiq/GR/yqaSM/9/g00=
+github.com/richardlehane/msoleps v1.0.4/go.mod h1:BWev5JBpU9Ko2WAgmZEuiz4/u3ZYTKbjLycmwiWUfWg=
+github.com/santhosh-tekuri/jsonschema/v6 v6.0.3 h1:1EYB5IzjZawrrnELUi78f9fPu57HuXjmddZPjrls/28=
+github.com/santhosh-tekuri/jsonschema/v6 v6.0.3/go.mod h1:JXeL+ps8p7/KNMjDQk3TCwPpBy0wYklyWTfbkIzdIFU=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/tiendc/go-deepcopy v1.6.0 h1:0UtfV/imoCwlLxVsyfUd4hNHnB3drXsfle+wzSCA5Wo=
+github.com/tiendc/go-deepcopy v1.6.0/go.mod h1:toXoeQoUqXOOS/X4sKuiAoSk6elIdqc0pN7MTgOOo2I=
+github.com/xuri/efp v0.0.1 h1:fws5Rv3myXyYni8uwj2qKjVaRP30PdjeYe2Y6FDsCL8=
+github.com/xuri/efp v0.0.1/go.mod h1:ybY/Jr0T0GTCnYjKqmdwxyxn2BQf2RcQIIvex5QldPI=
+github.com/xuri/excelize/v2 v2.9.1 h1:VdSGk+rraGmgLHGFaGG9/9IWu1nj4ufjJ7uwMDtj8Qw=
+github.com/xuri/excelize/v2 v2.9.1/go.mod h1:x7L6pKz2dvo9ejrRuD8Lnl98z4JLt0TGAwjhW+EiP8s=
+github.com/xuri/nfp v0.0.1 h1:MDamSGatIvp8uOmDP8FnmjuQpu90NzdJxo7242ANR9Q=
+github.com/xuri/nfp v0.0.1/go.mod h1:WwHg+CVyzlv/TX9xqBFXEZAuxOPxn2k1GNHwG41IIUQ=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
+golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
+golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
+golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
+golang.org/x/crypto v0.38.0 h1:jt+WWG8IZlBnVbomuhg2Mdq0+BBQaHbtqHEFEigjUV8=
+golang.org/x/crypto v0.38.0/go.mod h1:MvrbAqul58NNYPKnOra203SB9vpuZW0e+RRZV+Ggqjw=
+golang.org/x/image v0.25.0 h1:Y6uW6rH1y5y/LK1J8BPWZtr6yZ7hrsy6hFrXjgsc2fQ=
+golang.org/x/image v0.25.0/go.mod h1:tCAmOEGthTtkalusGp1g3xa2gke8J6c2N565dTyl9Rs=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
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+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
+golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=
+golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
+golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=
+golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
+golang.org/x/net v0.40.0 h1:79Xs7wF06Gbdcg4kdCCIQArK11Z1hr5POQ6+fIYHNuY=
+golang.org/x/net v0.40.0/go.mod h1:y0hY0exeL2Pku80/zKK7tpntoX23cqL3Oa6njdgRtds=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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diff --git a/workers/go/internal/contract/contract.go b/workers/go/internal/contract/contract.go
new file mode 100644
index 00000000..ba341c0b
--- /dev/null
+++ b/workers/go/internal/contract/contract.go
@@ -0,0 +1,120 @@
+package contract
+
+import (
+	"bytes"
+	"embed"
+	"encoding/json"
+	"fmt"
+	"io/fs"
+	"strings"
+
+	"github.com/santhosh-tekuri/jsonschema/v6"
+)
+
+//go:embed schemas/*.json
+var schemaFS embed.FS
+
+// ValidateHopEventJSON checks stdin against hop-event.schema.json.
+func ValidateHopEventJSON(data []byte) error {
+	return validate("hop-event.schema.json", data)
+}
+
+// ValidateEnvelopeListJSON checks stdout against envelope-list.schema.json.
+func ValidateEnvelopeListJSON(data []byte) error {
+	return validate("envelope-list.schema.json", data)
+}
+
+// ValidateWebCrawlerResultJSON checks crawler stdout against web-crawler-result.schema.json.
+func ValidateWebCrawlerResultJSON(data []byte) error {
+	return validate("web-crawler-result.schema.json", data)
+}
+
+// ValidateFileExtractorResultJSON checks extractor stdout against file-extractor-result.schema.json.
+func ValidateFileExtractorResultJSON(data []byte) error {
+	return validate("file-extractor-result.schema.json", data)
+}
+
+func validate(schemaName string, data []byte) error {
+	compiler := jsonschema.NewCompiler()
+	if err := loadSchemas(compiler); err != nil {
+		return err
+	}
+	schema, err := compiler.Compile(schemaCompileURL(schemaName))
+	if err != nil {
+		return fmt.Errorf("compile schema %s: %w", schemaName, err)
+	}
+	var value any
+	dec := json.NewDecoder(bytes.NewReader(data))
+	dec.UseNumber()
+	if err := dec.Decode(&value); err != nil {
+		return fmt.Errorf("invalid json: %w", err)
+	}
+	if err := schema.Validate(value); err != nil {
+		return fmt.Errorf("schema validation failed: %w", err)
+	}
+	return nil
+}
+
+const schemaBase = "https://derrick.local/schemas/"
+
+func loadSchemas(compiler *jsonschema.Compiler) error {
+	return fs.WalkDir(schemaFS, "schemas", func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() || !strings.HasSuffix(path, ".json") {
+			return nil
+		}
+		raw, err := schemaFS.ReadFile(path)
+		if err != nil {
+			return err
+		}
+		var doc any
+		if err := json.Unmarshal(raw, &doc); err != nil {
+			return fmt.Errorf("decode %s: %w", path, err)
+		}
+		name := strings.TrimPrefix(path, "schemas/")
+		ids := schemaResourceIDs(name, doc)
+		for _, id := range ids {
+			if err := compiler.AddResource(id, doc); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+}
+
+func schemaResourceIDs(filename string, doc any) []string {
+	seen := map[string]bool{}
+	add := func(id string) {
+		if id == "" || seen[id] {
+			return
+		}
+		seen[id] = true
+	}
+	add(schemaBase + filename)
+	if m, ok := doc.(map[string]any); ok {
+		if id, ok := m["$id"].(string); ok {
+			add(id)
+		}
+	}
+	ids := make([]string, 0, len(seen))
+	for id := range seen {
+		ids = append(ids, id)
+	}
+	return ids
+}
+
+func schemaCompileURL(name string) string {
+	raw, err := schemaFS.ReadFile("schemas/" + name)
+	if err != nil {
+		return schemaBase + name
+	}
+	var doc map[string]any
+	if err := json.Unmarshal(raw, &doc); err == nil {
+		if id, ok := doc["$id"].(string); ok && id != "" {
+			return id
+		}
+	}
+	return schemaBase + name
+}
diff --git a/workers/go/internal/contract/contract_test.go b/workers/go/internal/contract/contract_test.go
new file mode 100644
index 00000000..bd5d2291
--- /dev/null
+++ b/workers/go/internal/contract/contract_test.go
@@ -0,0 +1,49 @@
+package contract
+
+import "testing"
+
+func TestValidateHopEventAndEnvelopeList(t *testing.T) {
+	hop := []byte(`{"kind":"manual"}`)
+	if err := ValidateHopEventJSON(hop); err != nil {
+		t.Fatalf("hop event: %v", err)
+	}
+	env := []byte(`[{"verb":"result.emit","summary":"ok"}]`)
+	if err := ValidateEnvelopeListJSON(env); err != nil {
+		t.Fatalf("envelope list: %v", err)
+	}
+}
+
+func TestValidateEnvelopeListRejectsNestedAlias(t *testing.T) {
+	env := []byte(`[{"verb":"result.emit","result":{"emit":{"content":"x"}}}]`)
+	if err := ValidateEnvelopeListJSON(env); err == nil {
+		t.Fatal("expected rejection")
+	}
+}
+
+func TestValidateWebCrawlerResultAcceptsEmptyDiagnosticsArray(t *testing.T) {
+	payload := []byte(`{"ok":true,"start_url":"https://example.com/","pages":[],"stop_reason":"completed","requests_made":0,"bytes_read":0,"truncated":false,"diagnostics":[]}`)
+	if err := ValidateWebCrawlerResultJSON(payload); err != nil {
+		t.Fatalf("web crawler result: %v", err)
+	}
+}
+
+func TestValidateWebCrawlerResultRejectsNullDiagnostics(t *testing.T) {
+	payload := []byte(`{"ok":true,"start_url":"https://example.com/","pages":[],"stop_reason":"completed","requests_made":0,"bytes_read":0,"truncated":false,"diagnostics":null}`)
+	if err := ValidateWebCrawlerResultJSON(payload); err == nil {
+		t.Fatal("expected rejection for null diagnostics")
+	}
+}
+
+func TestValidateFileExtractorResultAcceptsEmptyFilesArray(t *testing.T) {
+	payload := []byte(`{"ok":true,"operation":"extract","files":[],"diagnostics":[]}`)
+	if err := ValidateFileExtractorResultJSON(payload); err != nil {
+		t.Fatalf("file extractor result: %v", err)
+	}
+}
+
+func TestValidateFileExtractorResultRejectsNullFiles(t *testing.T) {
+	payload := []byte(`{"ok":false,"operation":"extract","files":null,"diagnostics":[]}`)
+	if err := ValidateFileExtractorResultJSON(payload); err == nil {
+		t.Fatal("expected rejection for null files")
+	}
+}
diff --git a/workers/go/internal/contract/schemas/connector-contract.schema.json b/workers/go/internal/contract/schemas/connector-contract.schema.json
new file mode 100644
index 00000000..5ca68299
--- /dev/null
+++ b/workers/go/internal/contract/schemas/connector-contract.schema.json
@@ -0,0 +1,97 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/connector-contract.json",
+  "title": "Derrick connector protocol document",
+  "description": "Canonical host ops, emit shapes, allowed vendor-call ids, and success rules. Vendor HTTP bindings live in contracts/vendors/*.json.",
+  "type": "object",
+  "required": ["version", "ops", "scopes", "rules"],
+  "additionalProperties": false,
+  "properties": {
+    "version": { "type": "integer", "const": 1 },
+    "ops": {
+      "type": "object",
+      "required": ["sync_threads", "poll_inbox", "send_message"],
+      "additionalProperties": { "$ref": "#/$defs/op" }
+    },
+    "scopes": {
+      "type": "object",
+      "required": ["full_sync"],
+      "additionalProperties": { "$ref": "#/$defs/scope" }
+    },
+    "rules": {
+      "type": "object",
+      "required": [
+        "sync_threads_lists_tabs_only",
+        "poll_loads_one_conversation",
+        "paginate_within_op",
+        "live_http_results_accumulate",
+        "direct_test_poll_requires_non_empty_messages",
+        "direct_test_threads_requires_non_empty",
+        "runtime_empty_messages_ok_if_vendor_ok"
+      ],
+      "properties": {
+        "sync_threads_lists_tabs_only": { "type": "boolean" },
+        "poll_loads_one_conversation": { "type": "boolean" },
+        "paginate_within_op": { "type": "boolean" },
+        "live_http_results_accumulate": { "type": "boolean" },
+        "direct_test_poll_requires_non_empty_messages": { "type": "boolean" },
+        "direct_test_threads_requires_non_empty": { "type": "boolean" },
+        "runtime_empty_messages_ok_if_vendor_ok": { "type": "boolean" }
+      },
+      "additionalProperties": false
+    }
+  },
+  "$defs": {
+    "op": {
+      "type": "object",
+      "required": ["kind", "emit"],
+      "properties": {
+        "kind": { "type": "string", "enum": ["manual", "message_in_room"] },
+        "emit": { "type": "string", "enum": ["threads", "messages", "sent_message"] },
+        "params": { "type": "array", "items": { "type": "string" } },
+        "may_call": { "type": "array", "items": { "type": "string" } },
+        "must_not_call": { "type": "array", "items": { "type": "string" } },
+        "when_no_parent": { "$ref": "#/$defs/call_set" },
+        "when_parent": { "$ref": "#/$defs/call_set" },
+        "success": { "$ref": "#/$defs/success" },
+        "failure": { "$ref": "#/$defs/failure" }
+      },
+      "additionalProperties": false
+    },
+    "call_set": {
+      "type": "object",
+      "properties": {
+        "may_call": { "type": "array", "items": { "type": "string" } }
+      },
+      "additionalProperties": false
+    },
+    "success": {
+      "type": "object",
+      "properties": {
+        "empty_collection_ok": { "type": "boolean" },
+        "empty_array_ok_if_vendor_ok": { "type": "boolean" },
+        "requires_sent_message": { "type": "boolean" }
+      },
+      "additionalProperties": false
+    },
+    "failure": {
+      "type": "object",
+      "properties": {
+        "vendor_ok_false_empty_is_not_success": { "type": "boolean" },
+        "codes": { "type": "array", "items": { "type": "string" } }
+      },
+      "additionalProperties": false
+    },
+    "scope": {
+      "type": "object",
+      "required": ["ops", "include_reply_poll", "test_pagination"],
+      "properties": {
+        "ops": { "type": "array", "items": { "type": "string" } },
+        "include_reply_poll": { "type": "boolean" },
+        "test_pagination": { "type": "string", "enum": ["single_page", "follow_cursor"] },
+        "poll_must_not_call": { "type": "array", "items": { "type": "string" } }
+      },
+      "additionalProperties": false
+    }
+  }
+}
diff --git a/workers/go/internal/contract/schemas/connector-params.schema.json b/workers/go/internal/contract/schemas/connector-params.schema.json
new file mode 100644
index 00000000..32ba1a50
--- /dev/null
+++ b/workers/go/internal/contract/schemas/connector-params.schema.json
@@ -0,0 +1,20 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/connector-params.json",
+  "title": "Connector hop params",
+  "description": "params object on a connector plugin.invoke hop event.",
+  "type": "object",
+  "properties": {
+    "messaging_op": {
+      "type": "string",
+      "enum": ["sync_threads", "poll_inbox", "send_message"]
+    },
+    "vendor_thread_id": { "type": "string" },
+    "text": { "type": "string" },
+    "since": { "type": "string" },
+    "oldest": { "type": "string" },
+    "parent_vendor_message_id": { "type": "string" },
+    "thread_ts": { "type": "string" }
+  },
+  "additionalProperties": false
+}
diff --git a/workers/go/internal/contract/schemas/connector-result-emit.schema.json b/workers/go/internal/contract/schemas/connector-result-emit.schema.json
new file mode 100644
index 00000000..b67fcd14
--- /dev/null
+++ b/workers/go/internal/contract/schemas/connector-result-emit.schema.json
@@ -0,0 +1,54 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/connector-result-emit.json",
+  "title": "Connector result.emit payload",
+  "description": "Structured fields the host persists from a connector terminal envelope.",
+  "type": "object",
+  "additionalProperties": false,
+  "properties": {
+    "threads": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": ["vendor_thread_id", "title"],
+        "additionalProperties": false,
+        "properties": {
+          "vendor_thread_id": { "type": "string" },
+          "title": { "type": "string" },
+          "is_member": { "type": "boolean" },
+          "accessible": { "type": "boolean" }
+        }
+      }
+    },
+    "messages": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": ["vendor_thread_id", "vendor_message_id", "direction", "sender", "body", "created_at"],
+        "additionalProperties": false,
+        "properties": {
+          "vendor_thread_id": { "type": "string" },
+          "vendor_message_id": { "type": "string" },
+          "direction": { "type": "string", "enum": ["inbound", "outbound"] },
+          "sender": { "type": "string" },
+          "body": { "type": "string" },
+          "created_at": { "type": ["string", "number"] },
+          "parent_vendor_message_id": { "type": "string" },
+          "thread_ts": { "type": "string" },
+          "reply_count": { "type": "integer", "minimum": 0 }
+        }
+      }
+    },
+    "sent_message": {
+      "type": "object",
+      "required": ["vendor_message_id", "created_at"],
+      "additionalProperties": false,
+      "properties": {
+        "vendor_message_id": { "type": ["string", "number"] },
+        "created_at": { "type": ["string", "number"] }
+      }
+    },
+    "title": { "type": "string" },
+    "summary": { "type": "string" }
+  }
+}
diff --git a/workers/go/internal/contract/schemas/connector-vendor.schema.json b/workers/go/internal/contract/schemas/connector-vendor.schema.json
new file mode 100644
index 00000000..5959d2a2
--- /dev/null
+++ b/workers/go/internal/contract/schemas/connector-vendor.schema.json
@@ -0,0 +1,28 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/connector-vendor.schema.json",
+  "title": "Connector vendor profile",
+  "description": "HTTP bindings for one vendor. Call ids must match may_call / must_not_call in connector-contract.json.",
+  "type": "object",
+  "required": ["vendor", "vendor_ok_field", "calls"],
+  "additionalProperties": false,
+  "properties": {
+    "vendor": { "type": "string" },
+    "vendor_ok_field": { "type": "string" },
+    "membership_flag": { "type": "string" },
+    "pagination_cursor": { "type": "string" },
+    "calls": {
+      "type": "object",
+      "minProperties": 1,
+      "additionalProperties": {
+        "type": "object",
+        "required": ["method", "url"],
+        "additionalProperties": false,
+        "properties": {
+          "method": { "type": "string", "minLength": 1 },
+          "url": { "type": "string", "minLength": 1 }
+        }
+      }
+    }
+  }
+}
diff --git a/workers/go/internal/contract/schemas/envelope-list.schema.json b/workers/go/internal/contract/schemas/envelope-list.schema.json
new file mode 100644
index 00000000..5fbef6d8
--- /dev/null
+++ b/workers/go/internal/contract/schemas/envelope-list.schema.json
@@ -0,0 +1,55 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/envelope-list.json",
+  "title": "Guest stdout envelope list",
+  "description": "JSON array written to stdout by an offline guest (plugin or script). Canonical contract for all guest languages.",
+  "type": "array",
+  "minItems": 0,
+  "items": {
+    "type": "object",
+    "required": ["verb"],
+    "additionalProperties": false,
+    "properties": {
+      "verb": {
+        "type": "string",
+        "enum": [
+          "http.request",
+          "result.emit",
+          "message.post",
+          "ui.present",
+          "secret.request",
+          "storage.read",
+          "storage.write",
+          "job.schedule",
+          "log"
+        ]
+      },
+      "request_id": { "type": "string" },
+      "method": { "type": "string" },
+      "url": { "type": "string" },
+      "title": { "type": "string" },
+      "summary": { "type": "string" },
+      "text": { "type": "string" },
+      "content": { "type": "string" },
+      "html": { "type": "string" },
+      "markdown": { "type": "string" },
+      "message": { "type": "string" },
+      "schema_version": { "type": "integer" },
+      "auth_ref": { "type": ["string", "null"] },
+      "json": {
+        "description": "HTTP request body as a JSON value. HostHTTPRequest.json. The host sends this as the wire body."
+      },
+      "headers": { "type": "object", "additionalProperties": { "type": "string" } },
+      "widgets": { "type": "array", "items": { "type": "object" } },
+      "secret_ref": { "type": "string" },
+      "reason": { "type": "string" },
+      "key": { "type": "string" },
+      "value": true,
+      "interval_seconds": { "type": "integer" },
+      "timezone": { "type": "string" },
+      "threads": { "$ref": "connector-result-emit.schema.json#/properties/threads" },
+      "messages": { "$ref": "connector-result-emit.schema.json#/properties/messages" },
+      "sent_message": { "$ref": "connector-result-emit.schema.json#/properties/sent_message" }
+    }
+  }
+}
diff --git a/workers/go/internal/contract/schemas/execution-context-wire.schema.json b/workers/go/internal/contract/schemas/execution-context-wire.schema.json
new file mode 100644
index 00000000..b1529b66
--- /dev/null
+++ b/workers/go/internal/contract/schemas/execution-context-wire.schema.json
@@ -0,0 +1,46 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "ExecutionContextWire",
+  "type": "object",
+  "required": ["schema_version", "session_id", "principal"],
+  "properties": {
+    "schema_version": { "const": 1 },
+    "session_id": { "type": "string", "minLength": 1 },
+    "turn_id": { "type": "string" },
+    "agent_id": { "type": "string" },
+    "principal": { "type": "string", "minLength": 1 },
+    "workflow": {
+      "type": "object",
+      "properties": {
+        "workflow_id": { "type": "string" },
+        "kind": {
+          "type": "string",
+          "enum": [
+            "plugin_factory_create",
+            "plugin_factory_edit",
+            "connector_auth_discover",
+            "job_step",
+            "interactive_tool",
+            "none"
+          ]
+        },
+        "step_id": { "type": "string" },
+        "step_kind": { "type": "string" }
+      },
+      "additionalProperties": false
+    },
+    "delivery": {
+      "type": "string",
+      "enum": ["live_chat", "notification", "silent"]
+    },
+    "capabilities": {
+      "type": "array",
+      "items": {
+        "type": "string",
+        "enum": ["sync_web_crawl", "host_review_retry"]
+      },
+      "uniqueItems": true
+    }
+  },
+  "additionalProperties": false
+}
diff --git a/workers/go/internal/contract/schemas/file-extractor-result.schema.json b/workers/go/internal/contract/schemas/file-extractor-result.schema.json
new file mode 100644
index 00000000..c4e12bc4
--- /dev/null
+++ b/workers/go/internal/contract/schemas/file-extractor-result.schema.json
@@ -0,0 +1,7 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/file-extractor-result.json",
+  "title": "File extractor worker stdout",
+  "description": "JSON object written to stdout by derrick-file-extractor.",
+  "$ref": "worker-product.schema.json#/$defs/file_extractor_result"
+}
diff --git a/workers/go/internal/contract/schemas/guest-runtime.schema.json b/workers/go/internal/contract/schemas/guest-runtime.schema.json
new file mode 100644
index 00000000..03f4f622
--- /dev/null
+++ b/workers/go/internal/contract/schemas/guest-runtime.schema.json
@@ -0,0 +1,29 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/guest-runtime.json",
+  "title": "Derrick offline guest runtime",
+  "description": "Canonical I/O contract for script_exec and plugin.invoke guests. Trusted worker stdout (crawler, extractor) is defined in worker-product.schema.json. Swift host and Go workers must match these schemas.",
+  "type": "object",
+  "required": ["language", "stdin", "stdout"],
+  "additionalProperties": false,
+  "properties": {
+    "language": {
+      "type": "string",
+      "const": "go",
+      "description": "Guest implementation language."
+    },
+    "stdin": {
+      "description": "One hop event JSON object read from standard input.",
+      "$ref": "hop-event.schema.json"
+    },
+    "stdout": {
+      "description": "Envelope list JSON array written to standard output.",
+      "$ref": "envelope-list.schema.json"
+    },
+    "binary": {
+      "type": "string",
+      "const": "/tmp/guest",
+      "description": "Linux guest binary path inside the worker container."
+    }
+  }
+}
diff --git a/workers/go/internal/contract/schemas/hop-event.schema.json b/workers/go/internal/contract/schemas/hop-event.schema.json
new file mode 100644
index 00000000..a183e284
--- /dev/null
+++ b/workers/go/internal/contract/schemas/hop-event.schema.json
@@ -0,0 +1,42 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/hop-event.json",
+  "title": "Guest stdin hop event",
+  "description": "JSON object read from stdin when the host invokes an offline guest. Canonical contract for all guest languages.",
+  "type": "object",
+  "required": ["kind"],
+  "properties": {
+    "kind": {
+      "type": "string",
+      "enum": [
+        "manual",
+        "schedule",
+        "message_in_room",
+        "http_results",
+        "ui_action",
+        "grant_ready",
+        "harness",
+        "script"
+      ]
+    },
+    "http_results": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": ["request_id", "status"],
+        "additionalProperties": false,
+        "properties": {
+          "request_id": { "type": "string" },
+          "status": { "type": "integer" },
+          "headers": { "type": "object", "additionalProperties": { "type": "string" } },
+          "body": { "type": "string" },
+          "error": { "type": ["string", "null"] }
+        }
+      }
+    },
+    "params": {
+      "$ref": "connector-params.schema.json"
+    }
+  },
+  "additionalProperties": false
+}
diff --git a/workers/go/internal/contract/schemas/script-exec-contract.schema.json b/workers/go/internal/contract/schemas/script-exec-contract.schema.json
new file mode 100644
index 00000000..2e369012
--- /dev/null
+++ b/workers/go/internal/contract/schemas/script-exec-contract.schema.json
@@ -0,0 +1,346 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/script-exec-contract.json",
+  "title": "Derrick script_exec protocol document",
+  "description": "Canonical guest runtime, workflow, output, agent, and reviewer rules for script_exec and offline Go guests.",
+  "type": "object",
+  "required": [
+    "version",
+    "runtime",
+    "io",
+    "workflow",
+    "output",
+    "agent",
+    "review",
+    "rules",
+    "plugin_factory"
+  ],
+  "additionalProperties": false,
+  "properties": {
+    "version": { "type": "integer", "const": 1 },
+    "runtime": { "$ref": "#/$defs/runtime" },
+    "io": { "$ref": "#/$defs/io" },
+    "workflow": { "$ref": "#/$defs/workflow" },
+    "output": { "$ref": "#/$defs/output" },
+    "agent": { "$ref": "#/$defs/agent" },
+    "review": { "$ref": "#/$defs/review" },
+    "rules": { "$ref": "#/$defs/rules" },
+    "plugin_factory": { "$ref": "#/$defs/plugin_factory" }
+  },
+  "$defs": {
+    "runtime": {
+      "type": "object",
+      "required": [
+        "language",
+        "package",
+        "binary",
+        "stdlib_only",
+        "forbidden_imports",
+        "allowed_os_usage",
+        "example_go"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "language": { "type": "string", "const": "go" },
+        "package": { "type": "string", "const": "main" },
+        "binary": { "type": "string", "const": "/tmp/guest" },
+        "stdlib_only": { "type": "boolean" },
+        "forbidden_imports": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "allowed_os_usage": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "example_go": { "type": "string", "minLength": 1 }
+      }
+    },
+    "io": {
+      "type": "object",
+      "required": ["stdin_schema", "stdout_schema", "guest_runtime_schema"],
+      "additionalProperties": false,
+      "properties": {
+        "stdin_schema": { "type": "string", "const": "hop-event.schema.json" },
+        "stdout_schema": { "type": "string", "const": "envelope-list.schema.json" },
+        "guest_runtime_schema": { "type": "string", "const": "guest-runtime.schema.json" }
+      }
+    },
+    "workflow": {
+      "type": "object",
+      "required": [
+        "first_hop_verbs",
+        "http_results_event_kind",
+        "terminal_verbs",
+        "match_http_by",
+        "http_results_accumulate",
+        "post_body_field"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "first_hop_verbs": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "http_results_event_kind": { "type": "string" },
+        "terminal_verbs": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "match_http_by": { "type": "string", "const": "request_id" },
+        "http_results_accumulate": { "type": "boolean" },
+        "post_body_field": { "type": "string", "const": "json" }
+      }
+    },
+    "output": {
+      "type": "object",
+      "required": ["fields", "forbidden_patterns", "raw_body_in_content_requires_explicit_user_request"],
+      "additionalProperties": false,
+      "properties": {
+        "fields": {
+          "type": "object",
+          "required": ["content", "summary", "html", "markdown"],
+          "additionalProperties": false,
+          "properties": {
+            "content": { "$ref": "#/$defs/output_field" },
+            "summary": { "$ref": "#/$defs/output_field" },
+            "html": { "$ref": "#/$defs/output_field" },
+            "markdown": { "$ref": "#/$defs/output_field" }
+          }
+        },
+        "forbidden_patterns": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "raw_body_in_content_requires_explicit_user_request": { "type": "boolean" }
+      }
+    },
+    "output_field": {
+      "type": "object",
+      "required": ["purpose"],
+      "additionalProperties": true,
+      "properties": {
+        "purpose": { "type": "string" },
+        "host_strips_incidental_markup": { "type": "boolean" },
+        "host_allowlist_sanitizes": { "type": "boolean" },
+        "prefer_content_for_extracted_text": { "type": "boolean" }
+      }
+    },
+    "agent": {
+      "type": "object",
+      "required": [
+        "prefer_direct_urls_over_serp_html",
+        "retry_with_different_urls_on_empty_fetch",
+        "max_correction_attempts_after_block"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "prefer_direct_urls_over_serp_html": { "type": "boolean" },
+        "retry_with_different_urls_on_empty_fetch": { "type": "boolean" },
+        "max_correction_attempts_after_block": { "type": "integer", "minimum": 0 }
+      }
+    },
+    "review": {
+      "type": "object",
+      "required": [
+        "fail_fast",
+        "response_schema",
+        "checks",
+        "do_not_deny_for",
+        "enforced_elsewhere"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "fail_fast": { "type": "boolean" },
+        "response_schema": {
+          "type": "object",
+          "required": [
+            "alignedWithRequest",
+            "confidence",
+            "suggestedAction",
+            "concerns",
+            "summary"
+          ],
+          "additionalProperties": false,
+          "properties": {
+            "alignedWithRequest": { "type": "string" },
+            "confidence": { "type": "string" },
+            "suggestedAction": { "type": "string" },
+            "concerns": { "type": "string" },
+            "summary": { "type": "string" }
+          }
+        },
+        "checks": {
+          "type": "array",
+          "minItems": 1,
+          "items": { "$ref": "#/$defs/review_check" }
+        },
+        "do_not_deny_for": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "enforced_elsewhere": {
+          "type": "array",
+          "items": { "type": "string" }
+        }
+      }
+    },
+    "review_check": {
+      "type": "object",
+      "required": ["id", "order", "description"],
+      "additionalProperties": false,
+      "properties": {
+        "id": { "type": "string" },
+        "order": { "type": "integer", "minimum": 1 },
+        "description": { "type": "string" },
+        "notes": {
+          "type": "array",
+          "items": { "type": "string" }
+        }
+      }
+    },
+    "rules": {
+      "type": "object",
+      "required": [
+        "guest_has_no_network",
+        "host_performs_http",
+        "host_applies_ssrf",
+        "static_verifier_enforces_imports",
+        "scheduler_timing_not_in_script",
+        "deterministic_output_required",
+        "stable_sort_and_dedupe_collections",
+        "no_time_random_uuid_for_visible_output",
+        "match_http_results_by_request_id"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "guest_has_no_network": { "type": "boolean" },
+        "host_performs_http": { "type": "boolean" },
+        "host_applies_ssrf": { "type": "boolean" },
+        "static_verifier_enforces_imports": { "type": "boolean" },
+        "scheduler_timing_not_in_script": { "type": "boolean" },
+        "deterministic_output_required": { "type": "boolean" },
+        "stable_sort_and_dedupe_collections": { "type": "boolean" },
+        "no_time_random_uuid_for_visible_output": { "type": "boolean" },
+        "match_http_results_by_request_id": { "type": "boolean" }
+      }
+    },
+    "plugin_factory": {
+      "type": "object",
+      "required": ["manifest", "builder", "review"],
+      "additionalProperties": false,
+      "properties": {
+        "manifest": { "$ref": "#/$defs/plugin_factory_manifest" },
+        "builder": { "$ref": "#/$defs/plugin_factory_builder" },
+        "review": { "$ref": "#/$defs/plugin_factory_review" }
+      }
+    },
+    "plugin_factory_manifest": {
+      "type": "object",
+      "required": [
+        "host_creates_manifest",
+        "do_not_return_manifest_json",
+        "agent_plugin_schema",
+        "entrypoint",
+        "plugin_id_allowed_chars",
+        "plugin_id_forbidden_chars",
+        "roles",
+        "connector_messaging_ops",
+        "secret_kinds",
+        "never_embed_credentials_in_go_source",
+        "host_lists_connectors_under_messaging"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "host_creates_manifest": { "type": "boolean" },
+        "do_not_return_manifest_json": { "type": "boolean" },
+        "agent_plugin_schema": { "type": "string" },
+        "entrypoint": { "type": "string" },
+        "plugin_id_allowed_chars": { "type": "string" },
+        "plugin_id_forbidden_chars": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "roles": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "connector_messaging_ops": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "secret_kinds": {
+          "type": "array",
+          "items": { "type": "string" }
+        },
+        "never_embed_credentials_in_go_source": { "type": "boolean" },
+        "host_lists_connectors_under_messaging": { "type": "boolean" }
+      }
+    },
+    "plugin_factory_builder": {
+      "type": "object",
+      "required": [
+        "response_keys",
+        "skill_files_path_pattern",
+        "empty_skill_files_when_unused",
+        "test_input_is_serialized_json_object",
+        "test_input_must_not_be_empty",
+        "test_input_exercises_terminal_result",
+        "connector_test_input_uses_hops_array",
+        "connector_parse_json_http_results_when_vendor_returns_json"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "response_keys": {
+          "type": "array",
+          "items": { "type": "string" },
+          "minItems": 1
+        },
+        "skill_files_path_pattern": { "type": "string" },
+        "empty_skill_files_when_unused": { "type": "boolean" },
+        "test_input_is_serialized_json_object": { "type": "boolean" },
+        "test_input_must_not_be_empty": { "type": "boolean" },
+        "test_input_exercises_terminal_result": { "type": "boolean" },
+        "connector_test_input_uses_hops_array": { "type": "boolean" },
+        "connector_parse_json_http_results_when_vendor_returns_json": { "type": "boolean" }
+      }
+    },
+    "plugin_factory_review": {
+      "type": "object",
+      "required": [
+        "compilation_success_not_approval",
+        "response_schema",
+        "reject_non_go_source",
+        "reject_raw_network_outside_http_request_envelopes",
+        "reject_missing_stdin_read",
+        "source_derived_titles_may_be_fragments",
+        "reject_unsupported_direct_test_claims",
+        "connector_rules_document"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "compilation_success_not_approval": { "type": "boolean" },
+        "response_schema": {
+          "type": "object",
+          "required": ["decision", "summary", "findings"],
+          "additionalProperties": false,
+          "properties": {
+            "decision": { "type": "string" },
+            "summary": { "type": "string" },
+            "findings": { "type": "string" }
+          }
+        },
+        "reject_non_go_source": { "type": "boolean" },
+        "reject_raw_network_outside_http_request_envelopes": { "type": "boolean" },
+        "reject_missing_stdin_read": { "type": "boolean" },
+        "source_derived_titles_may_be_fragments": { "type": "boolean" },
+        "reject_unsupported_direct_test_claims": { "type": "boolean" },
+        "connector_rules_document": { "type": "string" }
+      }
+    }
+  }
+}
diff --git a/workers/go/internal/contract/schemas/web-crawler-result.schema.json b/workers/go/internal/contract/schemas/web-crawler-result.schema.json
new file mode 100644
index 00000000..9af39755
--- /dev/null
+++ b/workers/go/internal/contract/schemas/web-crawler-result.schema.json
@@ -0,0 +1,7 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/web-crawler-result.json",
+  "title": "Web crawler worker stdout",
+  "description": "JSON object written to stdout by derrick-web-crawler.",
+  "$ref": "worker-product.schema.json#/$defs/web_crawler_result"
+}
diff --git a/workers/go/internal/contract/schemas/worker-product.schema.json b/workers/go/internal/contract/schemas/worker-product.schema.json
new file mode 100644
index 00000000..874f6bfb
--- /dev/null
+++ b/workers/go/internal/contract/schemas/worker-product.schema.json
@@ -0,0 +1,97 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://derrick.local/schemas/worker-product.json",
+  "title": "Derrick trusted worker product contracts",
+  "description": "Shared stdout JSON contracts for prebuilt Go worker binaries (web crawler and file extractor). Swift host and Go workers must match these schemas.",
+  "$defs": {
+    "string_list": {
+      "type": "array",
+      "items": { "type": "string" }
+    },
+    "web_crawler_stop_reason": {
+      "type": "string",
+      "enum": [
+        "completed",
+        "max_pages",
+        "max_depth",
+        "timeout",
+        "total_bytes",
+        "queue_limit",
+        "cancelled",
+        "blocked"
+      ]
+    },
+    "web_crawler_page": {
+      "type": "object",
+      "required": ["url", "depth", "status_code", "title", "text", "links_found"],
+      "additionalProperties": false,
+      "properties": {
+        "url": { "type": "string" },
+        "depth": { "type": "integer" },
+        "status_code": { "type": "integer" },
+        "content_type": { "type": "string" },
+        "title": { "type": "string" },
+        "text": { "type": "string" },
+        "links_found": { "type": "integer" }
+      }
+    },
+    "web_crawler_result": {
+      "type": "object",
+      "required": [
+        "ok",
+        "start_url",
+        "pages",
+        "stop_reason",
+        "requests_made",
+        "bytes_read",
+        "truncated",
+        "diagnostics"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "ok": { "type": "boolean" },
+        "start_url": { "type": "string" },
+        "pages": {
+          "type": "array",
+          "items": { "$ref": "#/$defs/web_crawler_page" }
+        },
+        "stop_reason": { "$ref": "#/$defs/web_crawler_stop_reason" },
+        "requests_made": { "type": "integer" },
+        "bytes_read": { "type": "integer" },
+        "truncated": { "type": "boolean" },
+        "diagnostics": { "$ref": "#/$defs/string_list" }
+      }
+    },
+    "file_extractor_operation": {
+      "type": "string",
+      "enum": ["extract", "convert"]
+    },
+    "file_extractor_file_result": {
+      "type": "object",
+      "required": ["input_name", "kind", "byte_count"],
+      "additionalProperties": false,
+      "properties": {
+        "input_name": { "type": "string" },
+        "output_name": { "type": "string" },
+        "kind": { "type": "string" },
+        "byte_count": { "type": "integer" },
+        "preview": { "type": "string" },
+        "error": { "type": "string" }
+      }
+    },
+    "file_extractor_result": {
+      "type": "object",
+      "required": ["ok", "operation", "files", "diagnostics"],
+      "additionalProperties": false,
+      "properties": {
+        "ok": { "type": "boolean" },
+        "operation": { "$ref": "#/$defs/file_extractor_operation" },
+        "files": {
+          "type": "array",
+          "items": { "$ref": "#/$defs/file_extractor_file_result" }
+        },
+        "diagnostics": { "$ref": "#/$defs/string_list" }
+      }
+    }
+  }
+}
diff --git a/workers/go/internal/crawler/engine.go b/workers/go/internal/crawler/engine.go
new file mode 100644
index 00000000..890ea221
--- /dev/null
+++ b/workers/go/internal/crawler/engine.go
@@ -0,0 +1,372 @@
+package crawler
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/PuerkitoBio/goquery"
+)
+
+type extractedPage struct {
+	title  string
+	text   string
+	isHTML bool
+}
+
+func Run(ctx context.Context, req ValidatedRequest, proxy *ProxyConfig) Result {
+	deadline := time.Now().Add(time.Duration(req.TimeoutSeconds) * time.Second)
+	engine := &bfsEngine{
+		req:      req,
+		deadline: deadline,
+		proxy:    proxy,
+		client:   newHTTPClient(proxy),
+	}
+	return engine.run(ctx)
+}
+
+type queueItem struct {
+	url   *url.URL
+	depth int
+}
+
+type bfsEngine struct {
+	req           ValidatedRequest
+	deadline      time.Time
+	proxy         *ProxyConfig
+	client        *http.Client
+	queue         []queueItem
+	queuedKeys    map[string]bool
+	visitedKeys   map[string]bool
+	pageDepths    map[string]int
+	pages         []Page
+	pageIndexes   map[string]int
+	diagnostics   []string
+	stopReason    StopReason
+	reachedMaxDepth bool
+	requestsMade  int
+	bytesRead     int
+	lastRequestAt time.Time
+}
+
+func (e *bfsEngine) run(ctx context.Context) Result {
+	startKey := URLKey(e.req.StartURL)
+	e.queuedKeys = map[string]bool{startKey: true}
+	e.visitedKeys = map[string]bool{}
+	e.pageDepths = map[string]int{startKey: 0}
+	e.pageIndexes = map[string]int{}
+	e.queue = []queueItem{{url: e.req.StartURL, depth: 0}}
+
+	for len(e.queue) > 0 && e.stopReason == "" {
+		if time.Now().After(e.deadline) {
+			e.stopReason = StopTimeout
+			break
+		}
+		if len(e.pages) >= e.req.MaxPages {
+			e.stopReason = StopMaxPages
+			break
+		}
+		if ctx.Err() != nil {
+			e.stopReason = StopCancelled
+			break
+		}
+
+		next := e.queue[0]
+		e.queue = e.queue[1:]
+		key := URLKey(next.url)
+		delete(e.queuedKeys, key)
+
+		if !HostAllowed(e.req.AllowedHosts, next.url.Hostname()) || !IsHTTP(next.url) {
+			continue
+		}
+		if e.visitedKeys[key] {
+			continue
+		}
+		e.visitedKeys[key] = true
+		if len(e.visitedKeys) > e.req.MaxPages {
+			e.stopReason = StopMaxPages
+			break
+		}
+
+		e.visit(ctx, next.url, next.depth)
+	}
+
+	if e.stopReason == "" {
+		if e.reachedMaxDepth {
+			e.stopReason = StopMaxDepth
+		} else {
+			e.stopReason = StopCompleted
+		}
+	}
+
+	truncated := false
+	totalChars := 0
+	for i, p := range e.pages {
+		totalChars += len(p.Text)
+		if totalChars > MaximumOutputChars {
+			truncated = true
+			e.pages = e.pages[:i]
+			break
+		}
+	}
+
+	return Result{
+		OK:           e.stopReason != StopBlocked && len(e.pages) > 0,
+		StartURL:     e.req.StartURL.String(),
+		Pages:        e.pages,
+		StopReason:   e.stopReason,
+		RequestsMade: e.requestsMade,
+		BytesRead:    e.bytesRead,
+		Truncated:    truncated,
+		Diagnostics:  e.diagnostics,
+	}
+}
+
+func (e *bfsEngine) visit(ctx context.Context, pageURL *url.URL, depth int) {
+	if e.stopReason != "" || time.Now().After(e.deadline) {
+		return
+	}
+
+	normalized := NormalizeURL(pageURL)
+	e.requestsMade++
+	body, status, contentType, finalURL, err := e.fetch(ctx, normalized)
+	if err != nil {
+		e.diagnostics = append(e.diagnostics, fmt.Sprintf("%s: %s", normalized.String(), err.Error()))
+		return
+	}
+
+	e.bytesRead += len(body)
+	if e.bytesRead > MaximumTotalBytes {
+		e.stopReason = StopTotalBytes
+		return
+	}
+
+	extracted := extractContent(body, contentType, finalURL)
+	ct := contentType
+	page := Page{
+		URL:        finalURL.String(),
+		Depth:      depth,
+		StatusCode: status,
+		ContentType: func() *string {
+			if ct == "" {
+				return nil
+			}
+			return &ct
+		}(),
+		Title: extracted.title,
+		Text:  clipText(extracted.text, MaximumExtractedText),
+	}
+	e.pages = append(e.pages, page)
+	sourceKey := URLKey(finalURL)
+	e.pageIndexes[sourceKey] = len(e.pages) - 1
+	e.pageDepths[sourceKey] = depth
+
+	if !extracted.isHTML {
+		return
+	}
+
+	links := parseLinks(body, finalURL)
+	accepted := e.enqueueLinks(sourceKey, links)
+	idx := e.pageIndexes[sourceKey]
+	e.pages[idx].LinksFound = accepted
+}
+
+func (e *bfsEngine) enqueueLinks(sourceKey string, links []*url.URL) int {
+	sourceDepth := e.pageDepths[sourceKey]
+	accepted := 0
+	for _, link := range links {
+		if e.stopReason != "" {
+			break
+		}
+		if len(links) > MaximumLinksPerPage && accepted >= MaximumLinksPerPage {
+			break
+		}
+		normalized := NormalizeURL(link)
+		key := URLKey(normalized)
+		if !HostAllowed(e.req.AllowedHosts, normalized.Hostname()) || !IsHTTP(normalized) {
+			continue
+		}
+		if e.visitedKeys[key] || e.queuedKeys[key] {
+			continue
+		}
+		nextDepth := sourceDepth + 1
+		if nextDepth > e.req.MaxDepth {
+			e.reachedMaxDepth = true
+			continue
+		}
+		if len(e.queue) >= MaximumQueuedURLs {
+			e.stopReason = StopQueueLimit
+			break
+		}
+		e.queuedKeys[key] = true
+		e.pageDepths[key] = nextDepth
+		e.queue = append(e.queue, queueItem{url: normalized, depth: nextDepth})
+		accepted++
+	}
+	return accepted
+}
+
+func newHTTPClient(proxy *ProxyConfig) *http.Client {
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+	transport.Proxy = nil
+	if proxy != nil && proxy.Host != "" {
+		proxyURL, _ := url.Parse(fmt.Sprintf("http://%s:%d", proxy.Host, proxy.Port))
+		transport.Proxy = http.ProxyURL(proxyURL)
+		if proxy.Token != "" {
+			transport.ProxyConnectHeader = http.Header{
+				"X-Derrick-Crawler-Token": []string{proxy.Token},
+			}
+		}
+	}
+	return &http.Client{
+		Transport: transport,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+		Timeout: 20 * time.Second,
+	}
+}
+
+func (e *bfsEngine) fetch(ctx context.Context, start *url.URL) (body string, status int, contentType string, final *url.URL, err error) {
+	e.waitForSpacing()
+	current := start
+	redirected := map[string]bool{URLKey(start): true}
+
+	for i := 0; i <= MaximumRedirectsPerPage; i++ {
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, current.String(), nil)
+		if err != nil {
+			return "", 0, "", start, err
+		}
+		req.Header.Set("User-Agent", "DerrickWebCrawler/1")
+		req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+		req.Header.Set("Accept-Language", "en-US,en;q=0.9")
+		req.Header.Set("Accept-Encoding", "identity")
+		if e.proxy != nil && e.proxy.Token != "" {
+			req.Header.Set("X-Derrick-Crawler-Token", e.proxy.Token)
+		}
+
+		resp, err := e.client.Do(req)
+		if err != nil {
+			return "", 0, "", start, err
+		}
+		limited := io.LimitReader(resp.Body, int64(MaximumPageBytes))
+		data, err := io.ReadAll(limited)
+		resp.Body.Close()
+		if err != nil {
+			return "", 0, "", start, err
+		}
+		text := string(data)
+		ct := resp.Header.Get("Content-Type")
+
+		if resp.StatusCode < 300 || resp.StatusCode >= 400 {
+			return text, resp.StatusCode, ct, current, nil
+		}
+
+		location := resp.Header.Get("Location")
+		if location == "" {
+			return text, resp.StatusCode, ct, current, nil
+		}
+		redirectURL, err := url.Parse(location)
+		if err != nil {
+			return "", 0, "", start, fmt.Errorf("redirect left the start URL origin")
+		}
+		redirectURL = current.ResolveReference(redirectURL)
+		if !IsHTTP(redirectURL) {
+			return "", 0, "", start, fmt.Errorf("redirect left the start URL origin")
+		}
+		host := strings.ToLower(strings.TrimSpace(redirectURL.Hostname()))
+		if host == "" {
+			return "", 0, "", start, fmt.Errorf("redirect left the start URL origin")
+		}
+		e.req.AllowedHosts[host] = true
+		normalized := NormalizeURL(redirectURL)
+		key := URLKey(normalized)
+		if redirected[key] {
+			return "", 0, "", start, fmt.Errorf("redirect loop detected")
+		}
+		redirected[key] = true
+		current = normalized
+		e.waitForSpacing()
+	}
+	return "", 0, "", start, fmt.Errorf("redirect limit reached")
+}
+
+func (e *bfsEngine) waitForSpacing() {
+	if e.lastRequestAt.IsZero() {
+		e.lastRequestAt = time.Now()
+		return
+	}
+	elapsed := time.Since(e.lastRequestAt)
+	minimum := time.Duration(MinRequestDelayMS) * time.Millisecond
+	if elapsed < minimum {
+		time.Sleep(minimum - elapsed)
+	}
+	e.lastRequestAt = time.Now()
+}
+
+func extractContent(body string, contentType string, base *url.URL) extractedPage {
+	lower := strings.ToLower(contentType)
+	if strings.Contains(lower, "html") || strings.Contains(lower, "xhtml") {
+		return extractHTML(body)
+	}
+	prefix := body
+	if len(prefix) > MaximumExtractedText {
+		prefix = prefix[:MaximumExtractedText]
+	}
+	return extractedPage{title: "", text: prefix, isHTML: false}
+}
+
+func extractHTML(body string) extractedPage {
+	doc, err := goquery.NewDocumentFromReader(strings.NewReader(body))
+	if err != nil {
+		return extractedPage{text: body, isHTML: true}
+	}
+	doc.Find("script, style, noscript, template, svg").Remove()
+	title := strings.TrimSpace(doc.Find("title").First().Text())
+	text := strings.TrimSpace(doc.Find("body").Text())
+	if text == "" {
+		text = strings.TrimSpace(doc.Text())
+	}
+	return extractedPage{title: title, text: text, isHTML: true}
+}
+
+func parseLinks(body string, base *url.URL) []*url.URL {
+	doc, err := goquery.NewDocumentFromReader(strings.NewReader(body))
+	if err != nil {
+		return nil
+	}
+	var links []*url.URL
+	seen := map[string]bool{}
+	doc.Find("a[href]").Each(func(_ int, s *goquery.Selection) {
+		href, ok := s.Attr("href")
+		if !ok || strings.TrimSpace(href) == "" {
+			return
+		}
+		parsed, err := url.Parse(href)
+		if err != nil {
+			return
+		}
+		resolved := base.ResolveReference(parsed)
+		resolved.Fragment = ""
+		resolved.RawFragment = ""
+		resolved = NormalizeURL(resolved)
+		key := URLKey(resolved)
+		if seen[key] {
+			return
+		}
+		seen[key] = true
+		links = append(links, resolved)
+	})
+	return links
+}
+
+func clipText(text string, limit int) string {
+	if len(text) <= limit {
+		return text
+	}
+	return text[:limit]
+}
diff --git a/workers/go/internal/crawler/safety.go b/workers/go/internal/crawler/safety.go
new file mode 100644
index 00000000..4a7f80b5
--- /dev/null
+++ b/workers/go/internal/crawler/safety.go
@@ -0,0 +1,33 @@
+package crawler
+
+import "strings"
+
+var blockedPatterns = []struct {
+	substr string
+	reason string
+}{
+	{"ddos", "distributed denial-of-service behavior is not allowed."},
+	{"denial of service", "denial-of-service behavior is not allowed."},
+	{"dos attack", "denial-of-service behavior is not allowed."},
+	{"flood", "flooding a website is not allowed."},
+	{"hammer", "repeatedly hammering a website is not allowed."},
+	{"stress test", "load or stress testing a third-party website is not allowed."},
+	{"load test", "load or stress testing a third-party website is not allowed."},
+	{"port scan", "port scanning is not a web crawl."},
+	{"brute force", "brute-force activity is not allowed."},
+	{"infinite loop", "unbounded or infinite crawling is not allowed."},
+	{"loop forever", "unbounded or infinite crawling is not allowed."},
+	{"crawl forever", "unbounded or infinite crawling is not allowed."},
+	{"never stop crawling", "unbounded or infinite crawling is not allowed."},
+	{"unbounded crawl", "unbounded or infinite crawling is not allowed."},
+}
+
+func MaliciousGoalReason(goal string) string {
+	normalized := strings.ReplaceAll(strings.ReplaceAll(strings.ToLower(goal), "-", " "), "_", " ")
+	for _, p := range blockedPatterns {
+		if strings.Contains(normalized, p.substr) {
+			return p.reason
+		}
+	}
+	return ""
+}
diff --git a/workers/go/internal/crawler/types.go b/workers/go/internal/crawler/types.go
new file mode 100644
index 00000000..98f33e50
--- /dev/null
+++ b/workers/go/internal/crawler/types.go
@@ -0,0 +1,69 @@
+package crawler
+
+// Wire types mirror worker-product.schema.json (web_crawler_result) in Structure Contract.
+
+const (
+	DefaultMaxPages        = 10
+	MaximumMaxPages        = 100
+	DefaultMaxDepth        = 2
+	MaximumMaxDepth        = 5
+	DefaultTimeoutSeconds  = 120
+	MaximumTimeoutSeconds  = 900
+	MaximumPageBytes       = 1_048_576
+	MaximumTotalBytes      = 10 * 1_048_576
+	MaximumLinksPerPage    = 200
+	MaximumQueuedURLs      = 400
+	MaximumExtractedText   = 12_000
+	MaximumOutputChars     = 500_000
+	MaximumRedirectsPerPage = 5
+	MinRequestDelayMS      = 150
+)
+
+type Request struct {
+	StartURL       string   `json:"start_url"`
+	Goal           string   `json:"goal"`
+	MaxPages       int      `json:"max_pages"`
+	MaxDepth       int      `json:"max_depth"`
+	TimeoutSeconds int      `json:"timeout_seconds"`
+	AllowedHosts   []string `json:"allowed_hosts,omitempty"`
+}
+
+type Page struct {
+	URL         string  `json:"url"`
+	Depth       int     `json:"depth"`
+	StatusCode  int     `json:"status_code"`
+	ContentType *string `json:"content_type,omitempty"`
+	Title       string  `json:"title"`
+	Text        string  `json:"text"`
+	LinksFound  int     `json:"links_found"`
+}
+
+type StopReason string
+
+const (
+	StopCompleted  StopReason = "completed"
+	StopMaxPages   StopReason = "max_pages"
+	StopMaxDepth   StopReason = "max_depth"
+	StopTimeout    StopReason = "timeout"
+	StopTotalBytes StopReason = "total_bytes"
+	StopQueueLimit StopReason = "queue_limit"
+	StopCancelled  StopReason = "cancelled"
+	StopBlocked    StopReason = "blocked"
+)
+
+type Result struct {
+	OK            bool       `json:"ok"`
+	StartURL      string     `json:"start_url"`
+	Pages         []Page     `json:"pages"`
+	StopReason    StopReason `json:"stop_reason"`
+	RequestsMade  int        `json:"requests_made"`
+	BytesRead     int        `json:"bytes_read"`
+	Truncated     bool       `json:"truncated"`
+	Diagnostics   []string   `json:"diagnostics"`
+}
+
+type ProxyConfig struct {
+	Host  string
+	Port  int
+	Token string
+}
diff --git a/workers/go/internal/crawler/url.go b/workers/go/internal/crawler/url.go
new file mode 100644
index 00000000..b3c1400d
--- /dev/null
+++ b/workers/go/internal/crawler/url.go
@@ -0,0 +1,87 @@
+package crawler
+
+import (
+	"net"
+	"net/url"
+	"strings"
+)
+
+func IsHTTP(u *url.URL) bool {
+	scheme := strings.ToLower(u.Scheme)
+	return scheme == "http" || scheme == "https"
+}
+
+func NormalizeURL(u *url.URL) *url.URL {
+	if u == nil {
+		return u
+	}
+	clone := *u
+	clone.Scheme = strings.ToLower(clone.Scheme)
+	clone.Host = strings.ToLower(clone.Host)
+	clone.Fragment = ""
+	if clone.Path == "" {
+		clone.Path = "/"
+	}
+	if clone.Port() != "" {
+		if (clone.Scheme == "http" && clone.Port() == "80") ||
+			(clone.Scheme == "https" && clone.Port() == "443") {
+			clone.Host = clone.Hostname()
+		}
+	}
+	return &clone
+}
+
+func URLKey(u *url.URL) string {
+	return NormalizeURL(u).String()
+}
+
+func ParseStartURL(raw string) (*url.URL, error) {
+	u, err := url.Parse(strings.TrimSpace(raw))
+	if err != nil {
+		return nil, err
+	}
+	if !IsHTTP(u) {
+		return nil, errInvalidStartURL
+	}
+	host := strings.ToLower(strings.TrimSpace(u.Hostname()))
+	if host == "" {
+		return nil, errInvalidStartURL
+	}
+	if u.User != nil {
+		return nil, errInvalidStartURL
+	}
+	return NormalizeURL(u), nil
+}
+
+func ResolvedAllowedHosts(startHost string, explicit []string) map[string]bool {
+	hosts := map[string]bool{strings.ToLower(startHost): true}
+	for _, h := range explicit {
+		n := strings.ToLower(strings.TrimSpace(h))
+		if n != "" {
+			hosts[n] = true
+		}
+	}
+	return hosts
+}
+
+func HostAllowed(hosts map[string]bool, host string) bool {
+	return hosts[strings.ToLower(strings.TrimSpace(host))]
+}
+
+func IsPrivateHost(host string) bool {
+	host = strings.TrimSpace(strings.ToLower(host))
+	if host == "localhost" {
+		return true
+	}
+	ip := net.ParseIP(host)
+	if ip == nil {
+		return false
+	}
+	return ip.IsLoopback() || ip.IsPrivate() || ip.IsLinkLocalUnicast() || ip.IsLinkLocalMulticast()
+}
+
+var errInvalidStartURL = validationError("start_url must be an http or https URL without embedded credentials.")
+
+type validationError string
+
+func (e validationError) Error() string { return string(e) }
diff --git a/workers/go/internal/crawler/validate.go b/workers/go/internal/crawler/validate.go
new file mode 100644
index 00000000..ae08f384
--- /dev/null
+++ b/workers/go/internal/crawler/validate.go
@@ -0,0 +1,66 @@
+package crawler
+
+import (
+	"net/url"
+	"strings"
+)
+
+type ValidatedRequest struct {
+	StartURL       *url.URL
+	Goal           string
+	MaxPages       int
+	MaxDepth       int
+	TimeoutSeconds int
+	AllowedHosts   map[string]bool
+}
+
+func Validate(req Request) (ValidatedRequest, error) {
+	goal := strings.TrimSpace(req.Goal)
+	if goal == "" {
+		return ValidatedRequest{}, validationError("A crawl goal is required.")
+	}
+	if len(goal) > 2000 {
+		return ValidatedRequest{}, validationError("The crawl goal is too long.")
+	}
+	if reason := MaliciousGoalReason(goal); reason != "" {
+		return ValidatedRequest{}, validationError("Crawl blocked: " + reason)
+	}
+
+	maxPages := req.MaxPages
+	if maxPages == 0 {
+		maxPages = DefaultMaxPages
+	}
+	if maxPages < 1 || maxPages > MaximumMaxPages {
+		return ValidatedRequest{}, validationError("max_pages must be between 1 and 100.")
+	}
+
+	maxDepth := req.MaxDepth
+	if maxDepth == 0 {
+		maxDepth = DefaultMaxDepth
+	}
+	if maxDepth < 0 || maxDepth > MaximumMaxDepth {
+		return ValidatedRequest{}, validationError("max_depth must be between 0 and 5.")
+	}
+
+	timeout := req.TimeoutSeconds
+	if timeout == 0 {
+		timeout = DefaultTimeoutSeconds
+	}
+	if timeout < 1 || timeout > MaximumTimeoutSeconds {
+		return ValidatedRequest{}, validationError("timeout_seconds must be between 1 and 900.")
+	}
+
+	start, err := ParseStartURL(req.StartURL)
+	if err != nil {
+		return ValidatedRequest{}, err
+	}
+
+	return ValidatedRequest{
+		StartURL:       start,
+		Goal:           goal,
+		MaxPages:       maxPages,
+		MaxDepth:       maxDepth,
+		TimeoutSeconds: timeout,
+		AllowedHosts:   ResolvedAllowedHosts(start.Hostname(), req.AllowedHosts),
+	}, nil
+}
diff --git a/workers/go/internal/extractor/engine.go b/workers/go/internal/extractor/engine.go
new file mode 100644
index 00000000..6e86a4f4
--- /dev/null
+++ b/workers/go/internal/extractor/engine.go
@@ -0,0 +1,383 @@
+package extractor
+
+import (
+	"archive/zip"
+	"bytes"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/xuri/excelize/v2"
+)
+
+func Run(req Request, inputDir, outputDir string) Result {
+	if len(req.Files) == 0 {
+		return errorResult(req.Operation, "Choose at least one attached file.")
+	}
+	if len(req.Files) > MaximumFiles {
+		return errorResult(req.Operation, fmt.Sprintf("You can process at most %d files.", MaximumFiles))
+	}
+	if req.OutputFormat == "" {
+		req.OutputFormat = FormatMarkdown
+	}
+	if req.Operation == "" {
+		req.Operation = OperationExtract
+	}
+
+	var files []FileResult
+	var diagnostics []string
+	previewBudget := MaximumTotalPreviewChars
+
+	for _, name := range req.Files {
+		safeName, err := validatedFilename(name)
+		if err != nil {
+			files = append(files, FileResult{
+				InputName: name,
+				Kind:      kindFor(name),
+				Error:     strPtr(err.Error()),
+			})
+			continue
+		}
+		inputPath := filepath.Join(inputDir, safeName)
+		if _, err := os.Stat(inputPath); err != nil {
+			msg := fmt.Sprintf("%s was not found in /data/in.", safeName)
+			files = append(files, FileResult{
+				InputName: safeName,
+				Kind:      kindFor(safeName),
+				Error:     &msg,
+			})
+			continue
+		}
+
+		processed, err := process(inputPath, req.Operation, req.OutputFormat)
+		if err != nil {
+			msg := err.Error()
+			diagnostics = append(diagnostics, msg)
+			files = append(files, FileResult{
+				InputName: safeName,
+				Kind:      kindFor(safeName),
+				Error:     &msg,
+			})
+			continue
+		}
+		outPath := filepath.Join(outputDir, processed.OutputName)
+		if err := os.WriteFile(outPath, processed.Data, 0o644); err != nil {
+			msg := err.Error()
+			diagnostics = append(diagnostics, msg)
+			files = append(files, FileResult{
+				InputName: safeName,
+				Kind:      processed.Kind,
+				Error:     &msg,
+			})
+			continue
+		}
+		preview := clipPreview(processed.Preview, &previewBudget)
+		files = append(files, FileResult{
+			InputName:  safeName,
+			OutputName: &processed.OutputName,
+			Kind:       processed.Kind,
+			ByteCount:  len(processed.Data),
+			Preview:    preview,
+		})
+	}
+
+	ok := false
+	for _, f := range files {
+		if f.Error == nil {
+			ok = true
+			break
+		}
+	}
+	return Result{
+		OK:          ok,
+		Operation:   req.Operation,
+		Files:       files,
+		Diagnostics: diagnostics,
+	}
+}
+
+func errorResult(op Operation, message string) Result {
+	return Result{
+		OK:          false,
+		Operation:   op,
+		Files:       []FileResult{},
+		Diagnostics: []string{message},
+	}
+}
+
+type processedFile struct {
+	OutputName string
+	Kind       string
+	Data       []byte
+	Preview    string
+}
+
+func validatedFilename(name string) (string, error) {
+	trimmed := strings.TrimSpace(name)
+	if trimmed == "" || strings.Contains(trimmed, "/") || strings.Contains(trimmed, "\\") ||
+		strings.Contains(trimmed, "\x00") || trimmed == "." || trimmed == ".." {
+		return "", fmt.Errorf("%s is not a safe file name.", name)
+	}
+	base := filepath.Base(trimmed)
+	if base != trimmed {
+		return "", fmt.Errorf("%s is not a safe file name.", name)
+	}
+	return base, nil
+}
+
+func kindFor(filename string) string {
+	return strings.TrimPrefix(strings.ToLower(filepath.Ext(filename)), ".")
+}
+
+func process(path string, operation Operation, format OutputFormat) (processedFile, error) {
+	filename := filepath.Base(path)
+	fileKind := strings.TrimPrefix(strings.ToLower(filepath.Ext(filename)), ".")
+	extracted, err := extractText(path, fileKind)
+	if err != nil {
+		return processedFile{}, err
+	}
+
+	if operation == OperationExtract {
+		ext := "md"
+		body := extracted
+		if format == FormatTXT {
+			ext = "txt"
+		} else {
+			body = fmt.Sprintf("# %s\n\n%s\n", filename, extracted)
+		}
+		return processedFile{
+			OutputName: replaceExt(filename, ext),
+			Kind:       fileKind,
+			Data:       []byte(body),
+			Preview:    extracted,
+		}, nil
+	}
+
+	switch format {
+	case FormatXLSX:
+		if fileKind != "csv" && fileKind != "tsv" && fileKind != "txt" {
+			return processedFile{}, fmt.Errorf("That conversion is not supported for %s files.", fileKind)
+		}
+		csv := extracted
+		if fileKind == "tsv" {
+			csv = strings.ReplaceAll(extracted, "\t", ",")
+		}
+		data, err := csvToXLSX(csv)
+		if err != nil {
+			return processedFile{}, err
+		}
+		return processedFile{
+			OutputName: replaceExt(filename, "xlsx"),
+			Kind:       fileKind,
+			Data:       data,
+			Preview:    extracted,
+		}, nil
+	case FormatCSV:
+		if fileKind == "xlsx" {
+			raw, err := os.ReadFile(path)
+			if err != nil {
+				return processedFile{}, err
+			}
+			csv, err := xlsxToCSV(raw)
+			if err != nil {
+				return processedFile{}, err
+			}
+			return processedFile{
+				OutputName: replaceExt(filename, "csv"),
+				Kind:       fileKind,
+				Data:       []byte(csv),
+				Preview:    csv,
+			}, nil
+		}
+		if fileKind != "csv" && fileKind != "tsv" && fileKind != "txt" {
+			return processedFile{}, fmt.Errorf("That conversion is not supported for %s files.", fileKind)
+		}
+		return processedFile{
+			OutputName: replaceExt(filename, "csv"),
+			Kind:       fileKind,
+			Data:       []byte(extracted),
+			Preview:    extracted,
+		}, nil
+	default:
+		ext := "md"
+		body := extracted
+		if format == FormatTXT {
+			ext = "txt"
+		} else {
+			body = fmt.Sprintf("# %s\n\n%s\n", filename, extracted)
+		}
+		return processedFile{
+			OutputName: replaceExt(filename, ext),
+			Kind:       fileKind,
+			Data:       []byte(body),
+			Preview:    extracted,
+		}, nil
+	}
+}
+
+func extractText(path, kind string) (string, error) {
+	switch kind {
+	case "pdf":
+		return pdfToText(path)
+	case "docx":
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return "", err
+		}
+		return docxToText(raw)
+	case "xlsx":
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return "", err
+		}
+		return xlsxToCSV(raw)
+	case "html", "htm":
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return "", err
+		}
+		return htmlToText(string(raw)), nil
+	default:
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return "", err
+		}
+		return string(raw), nil
+	}
+}
+
+func pdfToText(path string) (string, error) {
+	if _, err := exec.LookPath("pdftotext"); err != nil {
+		return "", fmt.Errorf("PDF text extraction is unavailable in this image.")
+	}
+	out, err := exec.Command("pdftotext", "-layout", path, "-").Output()
+	if err != nil {
+		return "", fmt.Errorf("PDF text extraction failed.")
+	}
+	return string(out), nil
+}
+
+func docxToText(data []byte) (string, error) {
+	reader, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
+	if err != nil {
+		return "", err
+	}
+	for _, f := range reader.File {
+		if f.Name != "word/document.xml" {
+			continue
+		}
+		rc, err := f.Open()
+		if err != nil {
+			return "", err
+		}
+		defer rc.Close()
+		return parseDocxXML(rc)
+	}
+	return "", fmt.Errorf("document.xml missing from docx")
+}
+
+func parseDocxXML(r io.Reader) (string, error) {
+	decoder := xml.NewDecoder(r)
+	var parts []string
+	for {
+		tok, err := decoder.Token()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+		if se, ok := tok.(xml.StartElement); ok && se.Name.Local == "t" {
+			var text string
+			if err := decoder.DecodeElement(&text, &se); err != nil {
+				return "", err
+			}
+			if text != "" {
+				parts = append(parts, text)
+			}
+		}
+	}
+	return strings.Join(parts, ""), nil
+}
+
+func xlsxToCSV(data []byte) (string, error) {
+	book, err := excelize.OpenReader(bytes.NewReader(data))
+	if err != nil {
+		return "", err
+	}
+	sheets := book.GetSheetList()
+	if len(sheets) == 0 {
+		return "", nil
+	}
+	rows, err := book.GetRows(sheets[0])
+	if err != nil {
+		return "", err
+	}
+	var lines []string
+	for _, row := range rows {
+		lines = append(lines, strings.Join(row, ","))
+	}
+	return strings.Join(lines, "\n"), nil
+}
+
+func csvToXLSX(csv string) ([]byte, error) {
+	book := excelize.NewFile()
+	sheet := book.GetSheetName(0)
+	lines := strings.Split(csv, "\n")
+	for i, line := range lines {
+		if line == "" {
+			continue
+		}
+		cells := strings.Split(line, ",")
+		for j, cell := range cells {
+			cellName, _ := excelize.CoordinatesToCellName(j+1, i+1)
+			_ = book.SetCellValue(sheet, cellName, cell)
+		}
+	}
+	buf, err := book.WriteToBuffer()
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+func htmlToText(html string) string {
+	var out strings.Builder
+	inTag := false
+	for _, r := range html {
+		switch {
+		case r == '<':
+			inTag = true
+		case r == '>':
+			inTag = false
+			out.WriteRune(' ')
+		case !inTag:
+			out.WriteRune(r)
+		}
+	}
+	return strings.Join(strings.Fields(out.String()), " ")
+}
+
+func replaceExt(filename, ext string) string {
+	base := strings.TrimSuffix(filename, filepath.Ext(filename))
+	return base + "." + ext
+}
+
+func clipPreview(text string, remaining *int) *string {
+	if *remaining <= 0 {
+		return nil
+	}
+	limit := min(MaximumPreviewCharacters, *remaining)
+	preview := text
+	if len(preview) > limit {
+		preview = preview[:limit] + "…"
+	}
+	*remaining -= len(preview)
+	return &preview
+}
+
+func strPtr(s string) *string { return &s }
diff --git a/workers/go/internal/extractor/types.go b/workers/go/internal/extractor/types.go
new file mode 100644
index 00000000..6463359a
--- /dev/null
+++ b/workers/go/internal/extractor/types.go
@@ -0,0 +1,48 @@
+// Wire types mirror worker-product.schema.json (file_extractor_result) in Structure Contract.
+package extractor
+
+const (
+	InputDirectory             = "/data/in"
+	OutputDirectory            = "/data/out"
+	MaximumFiles               = 5
+	MaximumPreviewCharacters   = 8000
+	MaximumTotalPreviewChars   = 32000
+)
+
+type Operation string
+
+const (
+	OperationExtract Operation = "extract"
+	OperationConvert Operation = "convert"
+)
+
+type OutputFormat string
+
+const (
+	FormatMarkdown OutputFormat = "markdown"
+	FormatTXT      OutputFormat = "txt"
+	FormatCSV      OutputFormat = "csv"
+	FormatXLSX     OutputFormat = "xlsx"
+)
+
+type Request struct {
+	Operation    Operation    `json:"operation"`
+	OutputFormat OutputFormat `json:"output_format"`
+	Files        []string     `json:"files"`
+}
+
+type FileResult struct {
+	InputName  string  `json:"input_name"`
+	OutputName *string `json:"output_name,omitempty"`
+	Kind       string  `json:"kind"`
+	ByteCount  int     `json:"byte_count"`
+	Preview    *string `json:"preview,omitempty"`
+	Error      *string `json:"error,omitempty"`
+}
+
+type Result struct {
+	OK          bool         `json:"ok"`
+	Operation   Operation    `json:"operation"`
+	Files       []FileResult `json:"files"`
+	Diagnostics []string     `json:"diagnostics"`
+}