diff --git a/.github/workflows/verify.yml b/.github/workflows/verify.yml
index fd8afca..67f111b 100644
--- a/.github/workflows/verify.yml
+++ b/.github/workflows/verify.yml
@@ -16,5 +16,5 @@ jobs:
           cache: npm
       - run: npm ci
       - run: npm run verify
-      - run: git diff --exit-code -- packages/orbit-tags/runtime/dist/injected.js
+      - run: git diff --exit-code -- packages/orbit-tags/runtime/dist/injected.js packages/orbit-blur/runtime/dist/injected.js
       - run: npm run test:package
diff --git a/docs/source-layout.md b/docs/source-layout.md
index d1ed2d5..5724780 100644
--- a/docs/source-layout.md
+++ b/docs/source-layout.md
@@ -1,6 +1,6 @@
 # Source structure and dependency rules
 
-OrbitAI uses two independently versioned packages. Directory boundaries describe execution environments and ownership; they are not additional npm packages. `npm run check` validates imports using a TypeScript-capable AST parser and rejects runtime import cycles.
+OrbitAI uses independently versioned packages. Directory boundaries describe execution environments and ownership; they are not additional npm packages. `npm run check` validates imports using a TypeScript-capable AST parser and rejects runtime import cycles.
 
 ## Orbit
 
@@ -63,9 +63,21 @@ packages/orbit-tags/
 
 Orbit snapshots the business package without flattening its compiled hierarchy. The plugin manifest loads `dist/runtime/src/service/activate.js`; the diagnostic controller does not write platform configuration. Tags uses module ID `orbit-tags`; its package snapshot records the assigned data directory. See [installation ownership](orbit-platform-design.md).
 
+## Orbit Blur
+
+```text
+packages/orbit-blur/
+├── src/                        # Renderer TypeScript (style injection)
+├── scripts/build.mjs           # esbuild IIFE → runtime/dist/injected.js
+├── runtime/dist/injected.js    # Tracked browser bundle
+└── orbit-plugin.json           # Manifest (renderer-only, no service)
+```
+
+Renderer-only plugin: transparent backgrounds plus `backdrop-filter` blur. It imports type-only `@c0sc0s/orbit/sdk`. No private Codex selectors and no Orbit implementation imports.
+
 ## Verification and change discipline
 
-- `npm run build`: clean only each package's generated Node directory, build Orbit first, then Tags and its browser bundle.
+- `npm run build`: clean only each package's generated Node directory, build Orbit first, then Tags, then Blur and its browser bundle.
 - `npm run check`: syntax, package boundaries, source-layer dependencies, runtime cycles and documentation links.
 - `npm run typecheck`: strict implementation checks and public SDK contract tests.
 - Browser typechecks explicitly exclude Node ambient types, preventing accidental use of Node globals in renderer code.
diff --git a/package-lock.json b/package-lock.json
index cd5c681..e2db43c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -508,6 +508,10 @@
       "resolved": "packages/orbit",
       "link": true
     },
+    "node_modules/@c0sc0s/orbit-blur": {
+      "resolved": "packages/orbit-blur",
+      "link": true
+    },
     "node_modules/@c0sc0s/orbit-tags": {
       "resolved": "packages/orbit-tags",
       "link": true
@@ -11305,6 +11309,19 @@
         "node": ">=22"
       }
     },
+    "packages/orbit-blur": {
+      "name": "@c0sc0s/orbit-blur",
+      "version": "0.1.0",
+      "license": "UNLICENSED",
+      "devDependencies": {
+        "@c0sc0s/orbit": "0.5.2",
+        "esbuild": "0.28.2",
+        "typescript": "7.0.2"
+      },
+      "engines": {
+        "node": ">=22"
+      }
+    },
     "packages/orbit-tags": {
       "name": "@c0sc0s/orbit-tags",
       "version": "0.9.0",
diff --git a/package.json b/package.json
index b1883f7..bdc0933 100644
--- a/package.json
+++ b/package.json
@@ -10,7 +10,7 @@
     "node": ">=22.13.0"
   },
   "scripts": {
-    "build": "npm run build -w @c0sc0s/orbit && npm run build -w @c0sc0s/orbit-tags",
+    "build": "npm run build -w @c0sc0s/orbit && npm run build -w @c0sc0s/orbit-tags && npm run build -w @c0sc0s/orbit-blur",
     "check": "node scripts/check.mjs && node scripts/check-architecture.mjs",
     "typecheck": "npm run typecheck --workspaces --if-present",
     "test": "node --test scripts/test/*.test.mjs && npm test --workspaces --if-present",
diff --git a/packages/orbit-blur/README.md b/packages/orbit-blur/README.md
new file mode 100644
index 0000000..f14746a
--- /dev/null
+++ b/packages/orbit-blur/README.md
@@ -0,0 +1,11 @@
+# @c0sc0s/orbit-blur
+
+Renderer-only Orbit plugin. Injects transparent page backgrounds and `backdrop-filter` Gaussian blur on Codex chrome.
+
+```sh
+npm run build -w @c0sc0s/orbit-blur
+orbit plugin add ./packages/orbit-blur
+orbit plugin enable orbit-blur
+```
+
+Bump `runtimeVersion` in `orbit-plugin.json` (and `RUNTIME_VERSION` in source) after injected changes, then rebuild and re-add/apply. The tracked bundle is `runtime/dist/injected.js`.
diff --git a/packages/orbit-blur/orbit-plugin.json b/packages/orbit-blur/orbit-plugin.json
new file mode 100644
index 0000000..9b04fe5
--- /dev/null
+++ b/packages/orbit-blur/orbit-plugin.json
@@ -0,0 +1,8 @@
+{
+  "schemaVersion": 1,
+  "id": "orbit-blur",
+  "version": "0.1.0",
+  "runtimeVersion": "1.0.0",
+  "orbit": { "min": "0.5.0", "maxExclusive": "0.6.0" },
+  "renderer": "runtime/dist/injected.js"
+}
diff --git a/packages/orbit-blur/package.json b/packages/orbit-blur/package.json
new file mode 100644
index 0000000..0787bc9
--- /dev/null
+++ b/packages/orbit-blur/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "@c0sc0s/orbit-blur",
+  "version": "0.1.0",
+  "description": "Orbit plugin: transparent Codex chrome with Gaussian blur.",
+  "type": "module",
+  "files": [
+    "orbit-plugin.json",
+    "runtime/dist/",
+    "README.md"
+  ],
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org"
+  },
+  "license": "UNLICENSED",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/c0sc0s/codex-tags.git"
+  },
+  "scripts": {
+    "build": "node scripts/build.mjs",
+    "prepack": "npm run build",
+    "test": "npm run build && node --test test/*.test.mjs",
+    "typecheck": "tsc --noEmit -p tsconfig.json"
+  },
+  "engines": {
+    "node": ">=22"
+  },
+  "devDependencies": {
+    "@c0sc0s/orbit": "0.5.2",
+    "esbuild": "0.28.2",
+    "typescript": "7.0.2"
+  }
+}
diff --git a/packages/orbit-blur/runtime/dist/injected.js b/packages/orbit-blur/runtime/dist/injected.js
new file mode 100644
index 0000000..afe5405
--- /dev/null
+++ b/packages/orbit-blur/runtime/dist/injected.js
@@ -0,0 +1,125 @@
+"use strict";
+var CodexPlugin = (() => {
+  var __defProp = Object.defineProperty;
+  var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
+  var __getOwnPropNames = Object.getOwnPropertyNames;
+  var __hasOwnProp = Object.prototype.hasOwnProperty;
+  var __export = (target, all) => {
+    for (var name in all)
+      __defProp(target, name, { get: all[name], enumerable: true });
+  };
+  var __copyProps = (to, from, except, desc) => {
+    if (from && typeof from === "object" || typeof from === "function") {
+      for (let key of __getOwnPropNames(from))
+        if (!__hasOwnProp.call(to, key) && key !== except)
+          __defProp(to, key, { get: () => from[key], enumerable: !(desc = __getOwnPropDesc(from, key)) || desc.enumerable });
+    }
+    return to;
+  };
+  var __toCommonJS = (mod) => __copyProps(__defProp({}, "__esModule", { value: true }), mod);
+
+  // src/entry.ts
+  var entry_exports = {};
+  __export(entry_exports, {
+    activate: () => activate
+  });
+
+  // src/constants.ts
+  var RUNTIME_VERSION = "1.0.0";
+  var PLUGIN_ID = "orbit-blur";
+  var STYLE_ID = "orbit-blur-style";
+  var DEFAULT_BLUR_PX = 18;
+  var DEFAULT_TINT_OPACITY = 0.42;
+
+  // src/styles.ts
+  function clamp(value, min, max) {
+    return Math.min(max, Math.max(min, value));
+  }
+  function numberOption(value, fallback) {
+    return typeof value === "number" && Number.isFinite(value) ? value : fallback;
+  }
+  function resolveBlurSettings(config = {}) {
+    return {
+      blurPx: clamp(numberOption(config.blurPx, DEFAULT_BLUR_PX), 0, 64),
+      tintOpacity: clamp(numberOption(config.tintOpacity, DEFAULT_TINT_OPACITY), 0, 1)
+    };
+  }
+  function buildBlurStyles({ blurPx, tintOpacity }) {
+    const tintPercent = Math.round(tintOpacity * 100);
+    return `
+:root {
+  --orbit-blur-px: ${blurPx}px;
+  --orbit-blur-tint: color-mix(in srgb, Canvas ${tintPercent}%, transparent);
+  --orbit-blur-shell: color-mix(in srgb, Canvas ${Math.max(12, Math.round(tintPercent * 0.55))}%, transparent);
+}
+
+html, body {
+  background: transparent !important;
+  background-color: transparent !important;
+}
+
+:root {
+  --color-background: transparent;
+  --color-background-primary: transparent;
+  --color-bg: transparent;
+  --color-bg-primary: transparent;
+  --background: transparent;
+  --color-token-background: transparent;
+}
+
+aside,
+nav,
+header,
+[role="navigation"],
+[role="banner"],
+[role="complementary"] {
+  background-color: var(--orbit-blur-tint) !important;
+  backdrop-filter: blur(var(--orbit-blur-px)) saturate(1.15);
+  -webkit-backdrop-filter: blur(var(--orbit-blur-px)) saturate(1.15);
+}
+
+#root,
+#app,
+body > div:first-of-type {
+  background-color: var(--orbit-blur-shell) !important;
+  backdrop-filter: blur(var(--orbit-blur-px));
+  -webkit-backdrop-filter: blur(var(--orbit-blur-px));
+}
+
+[role="dialog"],
+[aria-modal="true"] {
+  backdrop-filter: blur(calc(var(--orbit-blur-px) * 0.65)) saturate(1.1);
+  -webkit-backdrop-filter: blur(calc(var(--orbit-blur-px) * 0.65)) saturate(1.1);
+}
+`.trim();
+  }
+
+  // src/entry.ts
+  function ensureStyleElement() {
+    const existing = document.getElementById(STYLE_ID);
+    if (existing instanceof HTMLStyleElement) return existing;
+    const style = document.createElement("style");
+    style.id = STYLE_ID;
+    (document.head ?? document.documentElement).appendChild(style);
+    return style;
+  }
+  async function activate(context) {
+    const settings = resolveBlurSettings(context.config);
+    const style = ensureStyleElement();
+    style.textContent = buildBlurStyles(settings);
+    context.onDispose(() => {
+      document.getElementById(STYLE_ID)?.remove();
+    });
+    return {
+      isActive: () => Boolean(document.getElementById(STYLE_ID)),
+      status: () => ({
+        plugin: PLUGIN_ID,
+        runtimeVersion: RUNTIME_VERSION,
+        active: Boolean(document.getElementById(STYLE_ID)),
+        blurPx: settings.blurPx,
+        tintOpacity: settings.tintOpacity
+      })
+    };
+  }
+  return __toCommonJS(entry_exports);
+})();
diff --git a/packages/orbit-blur/scripts/build.mjs b/packages/orbit-blur/scripts/build.mjs
new file mode 100644
index 0000000..67d9b50
--- /dev/null
+++ b/packages/orbit-blur/scripts/build.mjs
@@ -0,0 +1,36 @@
+import { build } from "esbuild";
+import { mkdir } from "node:fs/promises";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const projectRoot = dirname(dirname(fileURLToPath(import.meta.url)));
+const outputDirectory = join(projectRoot, "runtime", "dist");
+const testOutputDirectory = join(projectRoot, "dist");
+await mkdir(outputDirectory, { recursive: true });
+await mkdir(testOutputDirectory, { recursive: true });
+
+await build({
+  entryPoints: [join(projectRoot, "src", "entry.ts")],
+  outfile: join(outputDirectory, "injected.js"),
+  bundle: true,
+  format: "iife",
+  globalName: "CodexPlugin",
+  platform: "browser",
+  target: "chrome120",
+  minify: false,
+  sourcemap: false,
+  legalComments: "none",
+});
+
+// ESM helpers for Node tests (gitignored under packages/*/dist/).
+await build({
+  entryPoints: [join(projectRoot, "src", "styles.ts")],
+  outfile: join(testOutputDirectory, "styles.mjs"),
+  bundle: true,
+  format: "esm",
+  platform: "neutral",
+  target: "es2022",
+  minify: false,
+  sourcemap: false,
+  legalComments: "none",
+});
diff --git a/packages/orbit-blur/src/constants.ts b/packages/orbit-blur/src/constants.ts
new file mode 100644
index 0000000..da9f68c
--- /dev/null
+++ b/packages/orbit-blur/src/constants.ts
@@ -0,0 +1,9 @@
+/** Injected bundle cachebuster; keep in sync with orbit-plugin.json runtimeVersion. */
+export const RUNTIME_VERSION = "1.0.0";
+export const PLUGIN_ID = "orbit-blur";
+export const STYLE_ID = "orbit-blur-style";
+
+/** Soft glass: enough blur to read as frosted without smearing text. */
+export const DEFAULT_BLUR_PX = 18;
+/** Canvas tint opacity for frosted chrome (0–1). */
+export const DEFAULT_TINT_OPACITY = 0.42;
diff --git a/packages/orbit-blur/src/entry.ts b/packages/orbit-blur/src/entry.ts
new file mode 100644
index 0000000..0666b66
--- /dev/null
+++ b/packages/orbit-blur/src/entry.ts
@@ -0,0 +1,31 @@
+import type { RendererContext, RendererPlugin } from "@c0sc0s/orbit/sdk";
+import { PLUGIN_ID, RUNTIME_VERSION, STYLE_ID } from "./constants.js";
+import { buildBlurStyles, resolveBlurSettings } from "./styles.js";
+
+function ensureStyleElement(): HTMLStyleElement {
+  const existing = document.getElementById(STYLE_ID);
+  if (existing instanceof HTMLStyleElement) return existing;
+  const style = document.createElement("style");
+  style.id = STYLE_ID;
+  (document.head ?? document.documentElement).appendChild(style);
+  return style;
+}
+
+export async function activate(context: RendererContext): Promise<RendererPlugin> {
+  const settings = resolveBlurSettings(context.config);
+  const style = ensureStyleElement();
+  style.textContent = buildBlurStyles(settings);
+  context.onDispose(() => {
+    document.getElementById(STYLE_ID)?.remove();
+  });
+  return {
+    isActive: () => Boolean(document.getElementById(STYLE_ID)),
+    status: () => ({
+      plugin: PLUGIN_ID,
+      runtimeVersion: RUNTIME_VERSION,
+      active: Boolean(document.getElementById(STYLE_ID)),
+      blurPx: settings.blurPx,
+      tintOpacity: settings.tintOpacity,
+    }),
+  };
+}
diff --git a/packages/orbit-blur/src/styles.ts b/packages/orbit-blur/src/styles.ts
new file mode 100644
index 0000000..8e7c6cf
--- /dev/null
+++ b/packages/orbit-blur/src/styles.ts
@@ -0,0 +1,80 @@
+import {
+  DEFAULT_BLUR_PX,
+  DEFAULT_TINT_OPACITY,
+} from "./constants.js";
+
+export { DEFAULT_BLUR_PX, DEFAULT_TINT_OPACITY, RUNTIME_VERSION, PLUGIN_ID, STYLE_ID } from "./constants.js";
+
+export interface BlurSettings {
+  blurPx: number;
+  tintOpacity: number;
+}
+
+function clamp(value: number, min: number, max: number): number {
+  return Math.min(max, Math.max(min, value));
+}
+
+function numberOption(value: unknown, fallback: number): number {
+  return typeof value === "number" && Number.isFinite(value) ? value : fallback;
+}
+
+/** Resolve plugin config from Orbit loader entry; unknown keys are ignored. */
+export function resolveBlurSettings(config: Record<string, unknown> = {}): BlurSettings {
+  return {
+    blurPx: clamp(numberOption(config.blurPx, DEFAULT_BLUR_PX), 0, 64),
+    tintOpacity: clamp(numberOption(config.tintOpacity, DEFAULT_TINT_OPACITY), 0, 1),
+  };
+}
+
+export function buildBlurStyles({ blurPx, tintOpacity }: BlurSettings): string {
+  const tintPercent = Math.round(tintOpacity * 100);
+  // Landmark/role selectors only — no private Codex DOM attributes (those stay in orbit-tags).
+  // root transparency helps when the Electron host is already translucent; frosted chrome
+  // still blurs in-app content underneath via backdrop-filter either way.
+  return `
+:root {
+  --orbit-blur-px: ${blurPx}px;
+  --orbit-blur-tint: color-mix(in srgb, Canvas ${tintPercent}%, transparent);
+  --orbit-blur-shell: color-mix(in srgb, Canvas ${Math.max(12, Math.round(tintPercent * 0.55))}%, transparent);
+}
+
+html, body {
+  background: transparent !important;
+  background-color: transparent !important;
+}
+
+:root {
+  --color-background: transparent;
+  --color-background-primary: transparent;
+  --color-bg: transparent;
+  --color-bg-primary: transparent;
+  --background: transparent;
+  --color-token-background: transparent;
+}
+
+aside,
+nav,
+header,
+[role="navigation"],
+[role="banner"],
+[role="complementary"] {
+  background-color: var(--orbit-blur-tint) !important;
+  backdrop-filter: blur(var(--orbit-blur-px)) saturate(1.15);
+  -webkit-backdrop-filter: blur(var(--orbit-blur-px)) saturate(1.15);
+}
+
+#root,
+#app,
+body > div:first-of-type {
+  background-color: var(--orbit-blur-shell) !important;
+  backdrop-filter: blur(var(--orbit-blur-px));
+  -webkit-backdrop-filter: blur(var(--orbit-blur-px));
+}
+
+[role="dialog"],
+[aria-modal="true"] {
+  backdrop-filter: blur(calc(var(--orbit-blur-px) * 0.65)) saturate(1.1);
+  -webkit-backdrop-filter: blur(calc(var(--orbit-blur-px) * 0.65)) saturate(1.1);
+}
+`.trim();
+}
diff --git a/packages/orbit-blur/test/register.test.mjs b/packages/orbit-blur/test/register.test.mjs
new file mode 100644
index 0000000..05210bf
--- /dev/null
+++ b/packages/orbit-blur/test/register.test.mjs
@@ -0,0 +1,33 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { mkdtemp, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { createInstallationManager } from "@c0sc0s/orbit/installation";
+
+const packageRoot = dirname(dirname(fileURLToPath(import.meta.url)));
+
+test("Orbit registers orbit-blur as a renderer-only plugin", async (t) => {
+  const home = await mkdtemp(join(tmpdir(), "orbit-blur-register-"));
+  t.after(() => rm(home, { recursive: true, force: true }));
+  const manager = createInstallationManager({
+    home,
+    root: join(home, "orbit"),
+    platform: "darwin",
+    run: async (file, args) => {
+      if (args[1] !== "--help") throw new Error("Fixture must not start real Codex");
+      return { stdout: "Orbit", stderr: "" };
+    },
+  });
+  await manager.install();
+  const result = await manager.addPlugin(packageRoot);
+  assert.equal(result.status, "registered");
+  assert.equal(result.id, "orbit-blur");
+  const config = await manager.read();
+  const entry = config.plugins.find((plugin) => plugin.id === "orbit-blur");
+  assert.ok(entry);
+  assert.equal(entry.enabled, true);
+  assert.match(entry.entry, /runtime\/dist\/injected\.js$/);
+  assert.equal(entry.service, undefined);
+});
diff --git a/packages/orbit-blur/test/styles.test.mjs b/packages/orbit-blur/test/styles.test.mjs
new file mode 100644
index 0000000..d716167
--- /dev/null
+++ b/packages/orbit-blur/test/styles.test.mjs
@@ -0,0 +1,43 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { readFile } from "node:fs/promises";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { buildBlurStyles, resolveBlurSettings } from "../dist/styles.mjs";
+
+const root = dirname(dirname(fileURLToPath(import.meta.url)));
+
+test("resolveBlurSettings applies defaults and clamps", () => {
+  assert.deepEqual(resolveBlurSettings({}), {
+    blurPx: 18,
+    tintOpacity: 0.42,
+  });
+  assert.deepEqual(resolveBlurSettings({ blurPx: 99, tintOpacity: -1 }), {
+    blurPx: 64,
+    tintOpacity: 0,
+  });
+  assert.deepEqual(resolveBlurSettings({ blurPx: 12, tintOpacity: 0.5 }), {
+    blurPx: 12,
+    tintOpacity: 0.5,
+  });
+});
+
+test("buildBlurStyles includes blur tokens and landmark chrome", () => {
+  const css = buildBlurStyles({ blurPx: 20, tintOpacity: 0.4 });
+  assert.match(css, /--orbit-blur-px:\s*20px/);
+  assert.match(css, /backdrop-filter:\s*blur/);
+  assert.match(css, /\[role="navigation"\]/);
+  assert.match(css, /background:\s*transparent/);
+});
+
+test("orbit-plugin.json runtimeVersion matches injected bundle", async () => {
+  const manifest = JSON.parse(await readFile(join(root, "orbit-plugin.json"), "utf8"));
+  const injected = await readFile(join(root, "runtime", "dist", "injected.js"), "utf8");
+  assert.equal(manifest.id, "orbit-blur");
+  assert.equal(manifest.renderer, "runtime/dist/injected.js");
+  assert.equal(manifest.service, undefined);
+  assert.match(injected, /CodexPlugin/);
+  assert.match(injected, new RegExp(String.raw`RUNTIME_VERSION\s*=\s*"${manifest.runtimeVersion}"`));
+  assert.match(injected, /runtimeVersion:\s*RUNTIME_VERSION/);
+  assert.match(injected, /backdrop-filter/);
+});
diff --git a/packages/orbit-blur/tsconfig.json b/packages/orbit-blur/tsconfig.json
new file mode 100644
index 0000000..ef1029e
--- /dev/null
+++ b/packages/orbit-blur/tsconfig.json
@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "strict": true,
+    "types": [],
+    "noEmit": true,
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "skipLibCheck": true,
+    "verbatimModuleSyntax": true
+  },
+  "include": ["src/**/*.ts"]
+}
diff --git a/scripts/check.mjs b/scripts/check.mjs
index d4ca0cb..b23bf81 100644
--- a/scripts/check.mjs
+++ b/scripts/check.mjs
@@ -7,13 +7,13 @@ import { fileURLToPath } from "node:url";
 process.chdir(dirname(dirname(fileURLToPath(import.meta.url))));
 
 const run = promisify(execFile);
-for (const directory of ["packages/orbit/src", "packages/orbit-tags/runtime/src", "packages/orbit-tags/hooks", "scripts", "packages/orbit-tags/scripts", "packages/orbit-tags/bin"]) {
+for (const directory of ["packages/orbit/src", "packages/orbit-tags/runtime/src", "packages/orbit-tags/hooks", "scripts", "packages/orbit-tags/scripts", "packages/orbit-tags/bin", "packages/orbit-blur/scripts"]) {
   for (const file of await readdir(directory, { recursive: true })) {
     if (file.endsWith(".mjs")) await run(process.execPath, ["--check", join(directory, file)]);
   }
 }
 
-for (const workspace of ["orbit", "orbit-tags"]) {
+for (const workspace of ["orbit", "orbit-tags", "orbit-blur"]) {
   const root = resolve("packages", workspace);
   const manifest = JSON.parse(await readFile(join(root, "package.json"), "utf8"));
   if (workspace === "orbit" && Object.keys(manifest.dependencies ?? {}).some(name => !["figlet", "ora", "picocolors"].includes(name))) {
@@ -31,11 +31,20 @@ for (const workspace of ["orbit", "orbit-tags"]) {
         throw new Error(`Cross-workspace source import in ${workspace}/${file}: ${specifier}`);
       }
       if (workspace === "orbit" && specifier.startsWith("@c0sc0s/orbit-tags")) throw new Error("Orbit must not import Tags");
+      if (workspace === "orbit" && specifier.startsWith("@c0sc0s/orbit-blur")) throw new Error("Orbit must not import business plugins");
+      if (workspace === "orbit-blur" && specifier.startsWith("@c0sc0s/orbit") && specifier !== "@c0sc0s/orbit/sdk") {
+        throw new Error(`Blur plugin must use the SDK contract: ${file}`);
+      }
+      if (workspace === "orbit-blur" && specifier === "@c0sc0s/orbit/sdk") {
+        const typeOnly = /import\s+type\s+[^;]*from\s+["']@c0sc0s\/orbit\/sdk["']/u.test(source)
+          && !/import\s+(?!type\b)[^;]*from\s+["']@c0sc0s\/orbit\/sdk["']/u.test(source);
+        if (!typeOnly) throw new Error(`Blur plugin must import @c0sc0s/orbit/sdk as types only: ${file}`);
+      }
     }
   }
 }
 
-const documentation = ["README.md", "README.zh-CN.md", "CONTRIBUTING.md", "AGENTS.md", "CHANGELOG.md", "packages/orbit/README.md", "packages/orbit-tags/README.md", "packages/orbit-tags/README.zh-CN.md", "packages/orbit-tags/CHANGELOG.md"];
+const documentation = ["README.md", "README.zh-CN.md", "CONTRIBUTING.md", "AGENTS.md", "CHANGELOG.md", "packages/orbit/README.md", "packages/orbit-tags/README.md", "packages/orbit-tags/README.zh-CN.md", "packages/orbit-tags/CHANGELOG.md", "packages/orbit-blur/README.md"];
 for (const directory of ["docs", "packages/orbit/assets", "packages/orbit-tags/assets", "packages/orbit-tags/skills"]) {
   for (const file of await readdir(directory, { recursive: true })) {
     if (file.endsWith(".md")) documentation.push(join(directory, file));