diff --git a/context/effect-4/recipes/schema-codec-members.md b/context/effect-4/recipes/schema-codec-members.md
index fc6581074b..5c4f45bf64 100644
--- a/context/effect-4/recipes/schema-codec-members.md
+++ b/context/effect-4/recipes/schema-codec-members.md
@@ -76,6 +76,21 @@ The Date pair is another surviving-name trap: v3 `DateFromSelf` becomes v4 `Date
 wire schemas become v4 `DateFromString`. Keep those rewrites separate and follow the
 `schema-date` recipe for the wire contract.
 
+## Pretty-printed JSON
+
+V4 has no pretty-print JSON codec. `Schema.fromJsonString(S)` accepts no formatting options and
+serializes with plain `JSON.stringify`. When formatted JSON is a persisted wire format, encode the
+value with the schema and stringify the encoded JSON value separately:
+
+```ts
+const encoded = Schema.encodeSync(Config)(value)
+const content = JSON.stringify(encoded, null, 2)
+```
+
+Use `Schema.encodeEffect` instead when the surrounding path handles schema failures as an Effect.
+Preserve any existing trailing newline separately. Compare the resulting bytes against the v3
+baseline; accepting file churn is not a mechanical migration.
+
 ## Affected inventory
 
 The measured codec/member heatmap is:
diff --git a/packages/@overeng/megarepo/bin/mr.ts b/packages/@overeng/megarepo/bin/mr.ts
index f00e6ab46e..55966342a4 100644
--- a/packages/@overeng/megarepo/bin/mr.ts
+++ b/packages/@overeng/megarepo/bin/mr.ts
@@ -68,10 +68,9 @@ const program = Effect.gen(function* () {
     metricsExportInterval: 1000,
   })
 
-  yield* Cli.Command.run(mrCommand, {
-    name: 'mr',
+  yield* Cli.Command.runWith(mrCommand, {
     version,
-  })(rewriteHelpSubcommand(process.argv)).pipe(
+  })(rewriteHelpSubcommand(process.argv).slice(2)).pipe(
     Effect.scoped,
     CliVersion.enrichErrors,
     Effect.provideService(CliVersion, { name: 'mr', version }),
diff --git a/packages/@overeng/megarepo/src/cli/cli.integration.test.ts b/packages/@overeng/megarepo/src/cli/cli.integration.test.ts
index a23c0bc6bd..c4daf99477 100644
--- a/packages/@overeng/megarepo/src/cli/cli.integration.test.ts
+++ b/packages/@overeng/megarepo/src/cli/cli.integration.test.ts
@@ -7,7 +7,7 @@
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Exit, Option, Schema } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 import { expect } from 'vitest'
@@ -15,6 +15,7 @@ import { expect } from 'vitest'
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
 
 import { CONFIG_FILE_NAME_JSON, MegarepoConfig, validateMemberName } from '../lib/config.ts'
+import { encodePrettyJson } from '../lib/json.ts'
 import { makeConsoleCapture } from '../test-utils/consoleCapture.ts'
 import { initGitRepo, readConfig } from '../test-utils/setup.ts'
 import { mrCommand } from './mod.ts'
@@ -81,9 +82,7 @@ describe('mr init', () => {
             'https://raw.githubusercontent.com/overengineeringstudio/megarepo/main/schema/megarepo.schema.json',
           members: {},
         }
-        const configContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(initialConfig)
+        const configContent = yield* encodePrettyJson(MegarepoConfig)(initialConfig)
         yield* fs.writeFileString(configPath, configContent + '\n')
 
         // Verify config was created
@@ -119,9 +118,7 @@ describe('mr init', () => {
           workDir,
           EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
         )
-        const configContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(existingConfig)
+        const configContent = yield* encodePrettyJson(MegarepoConfig)(existingConfig)
         yield* fs.writeFileString(configPath, configContent + '\n')
 
         // Verify existing config
@@ -283,9 +280,7 @@ describe('mr add', () => {
           EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
         )
         const initialConfig: MegarepoConfig = { members: {} }
-        const initialContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(initialConfig)
+        const initialContent = yield* encodePrettyJson(MegarepoConfig)(initialConfig)
         yield* fs.writeFileString(configPath, initialContent + '\n')
 
         // Add a member
@@ -298,9 +293,7 @@ describe('mr add', () => {
           ...config,
           members: { ...config.members, [memberName]: memberSource },
         }
-        const updatedContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(updatedConfig)
+        const updatedContent = yield* encodePrettyJson(MegarepoConfig)(updatedConfig)
         yield* fs.writeFileString(configPath, updatedContent + '\n')
 
         // Verify member was added
@@ -339,9 +332,7 @@ describe('mr add', () => {
           ...config,
           members: { ...config.members, [customName]: memberSource },
         }
-        const updatedContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(updatedConfig)
+        const updatedContent = yield* encodePrettyJson(MegarepoConfig)(updatedConfig)
         yield* fs.writeFileString(configPath, updatedContent + '\n')
 
         const finalConfig = yield* readConfig(workDir)
@@ -379,9 +370,7 @@ describe('mr add', () => {
         const initialConfig: MegarepoConfig = {
           members: { effect: 'effect-ts/effect' },
         }
-        const initialContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(initialConfig)
+        const initialContent = yield* encodePrettyJson(MegarepoConfig)(initialConfig)
         yield* fs.writeFileString(configPath, initialContent + '\n')
 
         // Check that member already exists
@@ -428,7 +417,7 @@ describe('megarepo.json parsing', () => {
             local: './packages/local',
           },
         }
-        const content = yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+        const content = yield* encodePrettyJson(MegarepoConfig)(
           config,
         )
         yield* fs.writeFileString(configPath, content + '\n')
@@ -465,7 +454,7 @@ describe('megarepo.json parsing', () => {
             vscode: { enabled: true, exclude: ['large-repo'] },
           },
         }
-        const content = yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+        const content = yield* encodePrettyJson(MegarepoConfig)(
           config,
         )
         yield* fs.writeFileString(configPath, content + '\n')
@@ -496,7 +485,7 @@ const runRootWithCwd = ({ cwdPath }: { cwdPath: string }) =>
     const { consoleLayer, getStdoutLines } = yield* makeConsoleCapture
 
     const argv = ['node', 'mr', '--cwd', cwdPath, 'root', '--output', 'json']
-    const effect = Cli.Command.run(mrCommand, { name: 'mr', version: 'test' })(argv).pipe(
+    const effect = Cli.Command.runWith(mrCommand, { version: 'test' })(argv.slice(2)).pipe(
       Effect.provide(consoleLayer),
     )
     const exit = yield* Effect.exit(effect)
@@ -505,7 +494,7 @@ const runRootWithCwd = ({ cwdPath }: { cwdPath: string }) =>
 
     let state: RootState | undefined
     if (stdout.trim() !== '') {
-      state = yield* Schema.decodeUnknown(Schema.fromJsonString(RootState))(stdout)
+      state = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(RootState))(stdout)
     }
 
     return {
@@ -575,7 +564,7 @@ describe('--cwd option', () => {
 
         const cwdPath = '/nonexistent/path/that/does/not/exist/'
         const argv = ['node', 'mr', '--cwd', cwdPath, 'root', '--output', 'json']
-        const effect = Cli.Command.run(mrCommand, { name: 'mr', version: 'test' })(argv).pipe(
+        const effect = Cli.Command.runWith(mrCommand, { version: 'test' })(argv.slice(2)).pipe(
           Effect.provide(consoleLayer),
         )
         const exit = yield* Effect.exit(effect)
diff --git a/packages/@overeng/megarepo/src/cli/commands/check.ts b/packages/@overeng/megarepo/src/cli/commands/check.ts
index 1969c502b5..fcd6e9d78e 100644
--- a/packages/@overeng/megarepo/src/cli/commands/check.ts
+++ b/packages/@overeng/megarepo/src/cli/commands/check.ts
@@ -4,6 +4,7 @@ import * as Cli from 'effect/unstable/cli'
 import { EffectPath } from '@overeng/effect-path'
 
 import { readMegarepoConfig } from '../../lib/config.ts'
+import { encodePrettyJson } from '../../lib/json.ts'
 import { LOCK_FILE_NAME, readLockFile } from '../../lib/lock.ts'
 import { checkSourcePolicy, formatSourcePolicyViolation } from '../../lib/source-policy.ts'
 import { Cwd, findMegarepoRoot, jsonOption } from '../context.ts'
@@ -11,7 +12,7 @@ import { CheckCommandError, LockFileRequiredError, NotInMegarepoError } from '..
 import * as Observability from '../observability.ts'
 
 /** Encodes the structured check result as pretty-printed JSON for `--json` output. */
-const CheckReportJson = Schema.fromJsonString(Schema.Unknown, { space: 2 })
+const CheckReportJson = Schema.Unknown
 
 const allOption = Cli.Flag.boolean('all').pipe(
   Cli.Flag.withDescription('Check member source and lock files in repos/ as well as the root'),
@@ -63,7 +64,7 @@ export const checkCommand = Cli.Command.make(
       }
 
       if (json === true) {
-        yield* Console.log(yield* Schema.encode(CheckReportJson)(result))
+        yield* Console.log(yield* encodePrettyJson(CheckReportJson)(result))
       } else if (result.violations.length === 0) {
         yield* Console.log('Megarepo checks OK')
       } else {
diff --git a/packages/@overeng/megarepo/src/cli/commands/config/push-refs.ts b/packages/@overeng/megarepo/src/cli/commands/config/push-refs.ts
index f4f3eec6ff..bc2585ce27 100644
--- a/packages/@overeng/megarepo/src/cli/commands/config/push-refs.ts
+++ b/packages/@overeng/megarepo/src/cli/commands/config/push-refs.ts
@@ -6,7 +6,7 @@
  * Matching is done by canonical URL (org/repo), not by member name.
  */
 
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Option } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 import React from 'react'
diff --git a/packages/@overeng/megarepo/src/cli/commands/engine.ts b/packages/@overeng/megarepo/src/cli/commands/engine.ts
index b274aa8ae6..bd882f9ec3 100644
--- a/packages/@overeng/megarepo/src/cli/commands/engine.ts
+++ b/packages/@overeng/megarepo/src/cli/commands/engine.ts
@@ -8,10 +8,11 @@
 
 import { Prompt } from 'effect/unstable/cli'
 import type { ChildProcessSpawner as CommandExecutor } from 'effect/unstable/process'
-import type { Terminal } from 'effect/Terminal'
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
-import { Clock, Effect, Option, type ParseResult } from 'effect'
+import * as Terminal from 'effect/Terminal'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
+import { Clock, Effect, Option } from 'effect'
+import * as SchemaError from 'effect/SchemaError'
 import React from 'react'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
@@ -126,9 +127,9 @@ export const syncMegarepo = <R = never>({
   | StoreHygieneError
   | ConfigNotFoundError
   | PlatformError.PlatformError
-  | ParseResult.ParseError
+  | SchemaError.SchemaError
   | Error,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor | Store | StoreLock | R
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner | Store | StoreLock | R
 > =>
   Effect.gen(function* () {
     const { mode, dryRun, force, all, only, skip, gitProtocol, createBranches } = options
@@ -325,7 +326,7 @@ export const syncMegarepo = <R = never>({
 
             if (linkTarget !== null) {
               if (dryRun === false) {
-                yield* fs.remove(entryPath).pipe(Effect.catchAll(() => Effect.void))
+                yield* fs.remove(entryPath).pipe(Effect.catch(() => Effect.void))
               }
               return {
                 name: entry,
@@ -511,7 +512,7 @@ export const syncMegarepo = <R = never>({
                   ...(onMissingRef !== undefined ? { onMissingRef } : {}),
                 })
               }).pipe(
-                Effect.catchAll((error) =>
+                Effect.catch((error) =>
                   Effect.succeed({
                     root: nestedRoot,
                     results: [
@@ -594,7 +595,7 @@ const createMissingRefPrompt = (
     })
 
     return yield* prompt.pipe(
-      Effect.catchTag('QuitException', () => Effect.succeed('abort' as const)),
+      Effect.catchTag('QuitError', () => Effect.succeed('abort' as const)),
     )
   })
 
diff --git a/packages/@overeng/megarepo/src/cli/commands/ls.ts b/packages/@overeng/megarepo/src/cli/commands/ls.ts
index 312a818214..cd66efa319 100644
--- a/packages/@overeng/megarepo/src/cli/commands/ls.ts
+++ b/packages/@overeng/megarepo/src/cli/commands/ls.ts
@@ -4,9 +4,10 @@
  * List all members in the megarepo.
  */
 
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
-import { Effect, Option, type ParseResult } from 'effect'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
+import { Effect, Option } from 'effect'
+import * as SchemaError from 'effect/SchemaError'
 import * as Cli from 'effect/unstable/cli'
 import React from 'react'
 
@@ -50,7 +51,7 @@ const scanMembersRecursive = ({
   depth?: number
 }): Effect.Effect<
   MemberInfo[],
-  PlatformError.PlatformError | ParseResult.ParseError | Error,
+  PlatformError.PlatformError | SchemaError.SchemaError | Error,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
diff --git a/packages/@overeng/megarepo/src/cli/commands/status.ts b/packages/@overeng/megarepo/src/cli/commands/status.ts
index 696635bade..c9ec174412 100644
--- a/packages/@overeng/megarepo/src/cli/commands/status.ts
+++ b/packages/@overeng/megarepo/src/cli/commands/status.ts
@@ -5,9 +5,10 @@
  */
 
 import type { ChildProcessSpawner as CommandExecutor } from 'effect/unstable/process'
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
-import { Clock, Effect, Option, type ParseResult } from 'effect'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
+import { Clock, Effect, Option } from 'effect'
+import * as SchemaError from 'effect/SchemaError'
 import * as Cli from 'effect/unstable/cli'
 import React from 'react'
 
@@ -65,8 +66,8 @@ const scanMembersRecursive = ({
   depth?: number
 }): Effect.Effect<
   MemberStatus[],
-  PlatformError.PlatformError | ParseResult.ParseError | Error,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor | Store
+  PlatformError.PlatformError | SchemaError.SchemaError | Error,
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner | Store
 > =>
   Effect.gen(function* () {
     const enterResult = yield* traversal.enterRoot({ root: megarepoRoot, depth })
@@ -404,7 +405,7 @@ export const statusCommand = Cli.Command.make(
               })
               const memberRealPath = yield* fs
                 .realPath(memberSymlinkPath.replace(/\/$/, ''))
-                .pipe(Effect.catchAll(() => Effect.void))
+                .pipe(Effect.catch(() => Effect.void))
 
               if (memberRealPath !== undefined) {
                 const memberRealPathNorm = memberRealPath.replace(/\/$/, '')
diff --git a/packages/@overeng/megarepo/src/cli/context.ts b/packages/@overeng/megarepo/src/cli/context.ts
index 84ed25b777..a482b3bc53 100644
--- a/packages/@overeng/megarepo/src/cli/context.ts
+++ b/packages/@overeng/megarepo/src/cli/context.ts
@@ -6,7 +6,7 @@
 
 import { resolve } from 'node:path'
 
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Context, Effect, Layer, Option } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 
diff --git a/packages/@overeng/megarepo/src/cli/mod.ts b/packages/@overeng/megarepo/src/cli/mod.ts
index da17578d64..d0020c3ae6 100644
--- a/packages/@overeng/megarepo/src/cli/mod.ts
+++ b/packages/@overeng/megarepo/src/cli/mod.ts
@@ -73,7 +73,6 @@ export const mrCommand = Cli.Command.make('mr', { cwd: cwdOption }).pipe(
 )
 
 /** Exported CLI for external use */
-export const cli = Cli.Command.run(mrCommand, {
-  name: 'mr',
+export const cli = Cli.Command.runWith(mrCommand, {
   version: MR_VERSION,
-})(rewriteHelpSubcommand(process.argv))
+})(rewriteHelpSubcommand(process.argv).slice(2))
diff --git a/packages/@overeng/megarepo/src/cli/observability.ts b/packages/@overeng/megarepo/src/cli/observability.ts
index f58f031a21..484de35b19 100644
--- a/packages/@overeng/megarepo/src/cli/observability.ts
+++ b/packages/@overeng/megarepo/src/cli/observability.ts
@@ -78,7 +78,7 @@ const trustOtelContract = <A, E, R>(
   effect: Effect.Effect<A, E | OtelAttrEncodeError, R>,
 ): Effect.Effect<A, E, R> =>
   effect.pipe(
-    Effect.catchAll((error) =>
+    Effect.catch((error) =>
       typeof error === 'object' &&
       error !== null &&
       '_tag' in error &&
diff --git a/packages/@overeng/megarepo/src/cli/pin.integration.test.ts b/packages/@overeng/megarepo/src/cli/pin.integration.test.ts
index 2cd22fd95c..e64d2eb19a 100644
--- a/packages/@overeng/megarepo/src/cli/pin.integration.test.ts
+++ b/packages/@overeng/megarepo/src/cli/pin.integration.test.ts
@@ -7,7 +7,7 @@
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Option, Schema } from 'effect'
 import { expect } from 'vitest'
 
@@ -19,6 +19,7 @@ import {
   MegarepoConfig,
   parseSourceString,
 } from '../lib/config.ts'
+import { encodePrettyJson } from '../lib/json.ts'
 import {
   createLockedMember,
   LOCK_FILE_NAME,
@@ -52,7 +53,7 @@ const createMinimalTestSetup = () =>
         'test-repo': 'test-owner/test-repo',
       },
     }
-    const configContent = yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+    const configContent = yield* encodePrettyJson(MegarepoConfig)(
       config,
     )
     yield* fs.writeFileString(
@@ -101,9 +102,7 @@ describe('mr config pin', () => {
             workspacePath,
             EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
           )
-          const newConfigContent = yield* Schema.encode(
-            Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-          )(updatedConfig)
+          const newConfigContent = yield* encodePrettyJson(MegarepoConfig)(updatedConfig)
           yield* fs.writeFileString(configPath, newConfigContent + '\n')
 
           // Verify the update
@@ -135,7 +134,7 @@ describe('mr config pin', () => {
           }
           yield* fs.writeFileString(
             configPath,
-            (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(config1)) +
+            (yield* encodePrettyJson(MegarepoConfig)(config1)) +
               '\n',
           )
 
diff --git a/packages/@overeng/megarepo/src/cli/renderers/StatusOutput/schema.ts b/packages/@overeng/megarepo/src/cli/renderers/StatusOutput/schema.ts
index ee1575e246..cfc73ed639 100644
--- a/packages/@overeng/megarepo/src/cli/renderers/StatusOutput/schema.ts
+++ b/packages/@overeng/megarepo/src/cli/renderers/StatusOutput/schema.ts
@@ -260,10 +260,10 @@ export type StatusState = Schema.Schema.Type<typeof StatusState>
  *
  * Status is static output, so we only need SetState to populate the final result.
  */
-export const StatusAction = Schema.Union(
+export const StatusAction = Schema.Union([
   /** Replace entire state */
   Schema.TaggedStruct('SetState', { state: StatusState }),
-)
+])
 
 /** Inferred type for status actions. */
 export type StatusAction = Schema.Schema.Type<typeof StatusAction>
diff --git a/packages/@overeng/megarepo/src/cli/status.integration.test.ts b/packages/@overeng/megarepo/src/cli/status.integration.test.ts
index 92abdde009..709ec17645 100644
--- a/packages/@overeng/megarepo/src/cli/status.integration.test.ts
+++ b/packages/@overeng/megarepo/src/cli/status.integration.test.ts
@@ -9,7 +9,7 @@
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Exit, Schema } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 import { expect } from 'vitest'
@@ -17,6 +17,7 @@ import { expect } from 'vitest'
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
 
 import { MegarepoConfig } from '../lib/config.ts'
+import { encodePrettyJson } from '../lib/json.ts'
 import { createLockedMember, type LockFile, LOCK_FILE_NAME, writeLockFile } from '../lib/lock.ts'
 import { makeConsoleCapture } from '../test-utils/consoleCapture.ts'
 import {
@@ -43,7 +44,7 @@ const runStatusCommand = ({
     const { consoleLayer, getStdoutLines } = yield* makeConsoleCapture
 
     const argv = ['node', 'mr', '--cwd', cwd, 'status', '--output', 'json', ...args]
-    const effect = Cli.Command.run(mrCommand, { name: 'mr', version: 'test' })(argv).pipe(
+    const effect = Cli.Command.runWith(mrCommand, { version: 'test' })(argv.slice(2)).pipe(
       Effect.provide(consoleLayer),
     )
     const exit = yield* Effect.exit(effect)
@@ -53,7 +54,7 @@ const runStatusCommand = ({
     // Parse JSON output
     let status: StatusState | undefined
     if (stdout.trim() !== '') {
-      status = yield* Schema.decodeUnknown(Schema.fromJsonString(StatusState))(stdout)
+      status = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(StatusState))(stdout)
     }
 
     return {
@@ -89,7 +90,7 @@ const createTestWorkspace = (args: {
     const config: MegarepoConfig = {
       members: args.members,
     }
-    const configContent = yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+    const configContent = yield* encodePrettyJson(MegarepoConfig)(
       config,
     )
     yield* fs.writeFileString(
@@ -533,9 +534,7 @@ describe('mr status --output json', () => {
 
           const writeConfig = (workspacePath: AbsoluteDirPath, members: Record<string, string>) =>
             Effect.gen(function* () {
-              const configContent = yield* Schema.encode(
-                Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-              )({ members })
+              const configContent = yield* encodePrettyJson(MegarepoConfig)({ members })
               yield* fs.writeFileString(
                 EffectPath.ops.join(workspacePath, EffectPath.unsafe.relativeFile('megarepo.json')),
                 `${configContent}\n`,
diff --git a/packages/@overeng/megarepo/src/cli/store-gc-cold.integration.test.ts b/packages/@overeng/megarepo/src/cli/store-gc-cold.integration.test.ts
index f9b721cbd0..f38675ef0e 100644
--- a/packages/@overeng/megarepo/src/cli/store-gc-cold.integration.test.ts
+++ b/packages/@overeng/megarepo/src/cli/store-gc-cold.integration.test.ts
@@ -28,8 +28,8 @@
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { Clock, Effect, Exit, Layer, Schema } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 import { expect, vi } from 'vitest'
@@ -64,11 +64,12 @@ vi.setConfig({
 
 const git = (cwd: string, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...args).pipe(Command.workingDirectory(cwd))
-    return (yield* Command.string(command)).trim()
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', args, { cwd })
+    return (yield* spawner.string(command)).trim()
   })
 
-const liveClock = Clock.make()
+const liveClock = Clock.Clock.defaultValue()
 
 /**
  * Deterministic decision clock so grace/retention decisions are reproducible.
@@ -76,13 +77,12 @@ const liveClock = Clock.make()
  * deadlines instead of firing immediately under the fixed decision time.
  */
 const fixedClockLayer = (nowMs: number) =>
-  Layer.setClock({
-    [Clock.ClockTypeId]: Clock.ClockTypeId,
+  Layer.succeed(Clock.Clock, {
     currentTimeMillis: Effect.succeed(nowMs),
     currentTimeNanos: Effect.succeed(BigInt(nowMs) * 1_000_000n),
     sleep: (duration) => liveClock.sleep(duration),
-    unsafeCurrentTimeMillis: () => nowMs,
-    unsafeCurrentTimeNanos: () => BigInt(nowMs) * 1_000_000n,
+    currentTimeMillisUnsafe: () => nowMs,
+    currentTimeNanosUnsafe: () => BigInt(nowMs) * 1_000_000n,
   })
 
 const StoreGcJsonOutput = Schema.Struct({
@@ -129,7 +129,7 @@ const runGc = ({
     process.env['MEGAREPO_STORE'] = storePath
 
     const argv = ['node', 'mr', 'store', 'gc', ...args, '--output', 'json']
-    const exit = yield* Cli.Command.run(mrCommand, { name: 'mr', version: 'test' })(argv).pipe(
+    const exit = yield* Cli.Command.runWith(mrCommand, { version: 'test' })(argv.slice(2)).pipe(
       Effect.provideService(Cwd, cwd),
       Effect.provide(
         Layer.mergeAll(consoleLayer, makeStubPrStateResolverLayer(prRepos), fixedClockLayer(now)),
diff --git a/packages/@overeng/megarepo/src/cli/store-gc-otel.integration.test.ts b/packages/@overeng/megarepo/src/cli/store-gc-otel.integration.test.ts
index 96b1c3ab9d..7f0e2b0547 100644
--- a/packages/@overeng/megarepo/src/cli/store-gc-otel.integration.test.ts
+++ b/packages/@overeng/megarepo/src/cli/store-gc-otel.integration.test.ts
@@ -21,8 +21,8 @@
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { Clock, Effect, Layer, Option, Ref, Schema } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 import { expect } from 'vitest'
@@ -44,14 +44,15 @@ const NOW = Date.parse('2026-06-11T12:00:00.000Z')
 
 const git = (cwd: string, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...args).pipe(Command.workingDirectory(cwd))
-    return (yield* Command.string(command)).trim()
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', args, { cwd })
+    return (yield* spawner.string(command)).trim()
   })
 
 /**
  * Deterministic DECISION clock — `currentTime{Millis,Nanos}` are pinned to
  * `nowMs` so every grace/retention decision is reproducible — but `sleep`
- * delegates to a REAL live clock (`Clock.make()`) instead of the cold test's
+ * delegates to a REAL live clock (`Clock.Clock.defaultValue()`) instead of the cold test's
  * `() => Effect.void`.
  *
  * Why real sleep here: this test runs the gc with the OTEL exporter active, and
@@ -61,15 +62,14 @@ const git = (cwd: string, ...args: ReadonlyArray<string>) =>
  * still fixed) lets the infra timers tick on wall time while keeping gc decisions
  * deterministic — the root-cause fix, with no production workaround.
  */
-const liveClock = Clock.make()
+const liveClock = Clock.Clock.defaultValue()
 const fixedClockLayer = (nowMs: number) =>
-  Layer.setClock({
-    [Clock.ClockTypeId]: Clock.ClockTypeId,
+  Layer.succeed(Clock.Clock, {
     currentTimeMillis: Effect.succeed(nowMs),
     currentTimeNanos: Effect.succeed(BigInt(nowMs) * 1_000_000n),
     sleep: (duration) => liveClock.sleep(duration),
-    unsafeCurrentTimeMillis: () => nowMs,
-    unsafeCurrentTimeNanos: () => BigInt(nowMs) * 1_000_000n,
+    currentTimeMillisUnsafe: () => nowMs,
+    currentTimeNanosUnsafe: () => BigInt(nowMs) * 1_000_000n,
   })
 
 const REPO = { host: 'github.com', owner: 'acme', repo: 'widget' } as const
@@ -129,7 +129,7 @@ const runGc = ({
     process.env['MEGAREPO_STORE'] = storePath
 
     const argv = ['node', 'mr', 'store', 'gc', '--output', 'json']
-    yield* Cli.Command.run(mrCommand, { name: 'mr', version: 'test' })(argv).pipe(
+    yield* Cli.Command.runWith(mrCommand, { version: 'test' })(argv.slice(2)).pipe(
       Effect.provideService(Cwd, cwd),
       Effect.provideService(OtelConfig, { endpoint: telemetry }),
       Effect.provide(
diff --git a/packages/@overeng/megarepo/src/cli/store.integration.test.ts b/packages/@overeng/megarepo/src/cli/store.integration.test.ts
index 9591cf84b3..ebf417f86c 100644
--- a/packages/@overeng/megarepo/src/cli/store.integration.test.ts
+++ b/packages/@overeng/megarepo/src/cli/store.integration.test.ts
@@ -6,7 +6,7 @@
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Exit, Option, Schema } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 import { expect } from 'vitest'
@@ -79,7 +79,7 @@ const runMrCommand = ({
     )
 
     const argv = ['node', 'mr', ...command]
-    const exit = yield* Cli.Command.run(mrCommand, { name: 'mr', version: 'test' })(argv).pipe(
+    const exit = yield* Cli.Command.runWith(mrCommand, { version: 'test' })(argv.slice(2)).pipe(
       Effect.provideService(Cwd, cwd),
       Effect.provide(consoleLayer),
       Effect.exit,
@@ -525,7 +525,7 @@ describe('store discovery is bounded to the layout', () => {
           .remove(EffectPath.ops.join(wt, EffectPath.unsafe.relativeFile('.git')), {
             recursive: true,
           })
-          .pipe(Effect.catchAll(() => Effect.void))
+          .pipe(Effect.catch(() => Effect.void))
         for (const sub of ['node_modules/a/b/c', 'src/x/y', 'dist/p/q']) {
           yield* fs.makeDirectory(
             EffectPath.ops.join(wt, EffectPath.unsafe.relativeDir(`${sub}/`)),
diff --git a/packages/@overeng/megarepo/src/cli/sync.integration.test.ts b/packages/@overeng/megarepo/src/cli/sync.integration.test.ts
index b7482bfe1d..5088df0cb8 100644
--- a/packages/@overeng/megarepo/src/cli/sync.integration.test.ts
+++ b/packages/@overeng/megarepo/src/cli/sync.integration.test.ts
@@ -2,14 +2,15 @@ import { pathToFileURL } from 'node:url'
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { FileSystem } from 'effect/FileSystem'
-import { Cause, Chunk, Effect, Exit, Option, Schema } from 'effect'
+import * as FileSystem from 'effect/FileSystem'
+import { Cause, Effect, Exit, Option, Schema } from 'effect'
 import * as Cli from 'effect/unstable/cli'
 import { expect } from 'vitest'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
 
 import { CONFIG_FILE_NAME_JSON, MegarepoConfig } from '../lib/config.ts'
+import { encodePrettyJson } from '../lib/json.ts'
 import {
   checkLockStaleness,
   createEmptyLockFile,
@@ -146,7 +147,7 @@ const runMrCommand = ({
     )
 
     const argv = ['node', 'mr', ...command, ...args]
-    const effect = Cli.Command.run(mrCommand, { name: 'mr', version: 'test' })(argv).pipe(
+    const effect = Cli.Command.runWith(mrCommand, { version: 'test' })(argv.slice(2)).pipe(
       Effect.provideService(Cwd, cwd),
       Effect.provide(consoleLayer),
     )
@@ -632,9 +633,7 @@ const createNestedMegarepoFixture = () =>
         'grandchild-lib': grandchildPath,
       },
     }
-    const childConfigContent = yield* Schema.encode(
-      Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-    )(childConfig)
+    const childConfigContent = yield* encodePrettyJson(MegarepoConfig)(childConfig)
     yield* fs.writeFileString(
       EffectPath.ops.join(childPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
       childConfigContent + '\n',
@@ -658,9 +657,7 @@ const createNestedMegarepoFixture = () =>
         'child-megarepo': childPath,
       },
     }
-    const parentConfigContent = yield* Schema.encode(
-      Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-    )(parentConfig)
+    const parentConfigContent = yield* encodePrettyJson(MegarepoConfig)(parentConfig)
     yield* fs.writeFileString(
       EffectPath.ops.join(parentPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
       parentConfigContent + '\n',
@@ -702,7 +699,7 @@ describe('--all sync mode', () => {
 
           // Read parent config and verify it points to child
           const parentConfigContent = yield* fs.readFileString(parentConfigPath)
-          const parentConfig = yield* Schema.decodeUnknown(Schema.fromJsonString(MegarepoConfig))(
+          const parentConfig = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(MegarepoConfig))(
             parentConfigContent,
           )
           expect(parentConfig.members['child-megarepo']).toBe(childPath)
@@ -725,7 +722,7 @@ describe('--all sync mode', () => {
             EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
           )
           const childConfigContent = yield* fs.readFileString(childConfigPath)
-          const childConfig = yield* Schema.decodeUnknown(Schema.fromJsonString(MegarepoConfig))(
+          const childConfig = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(MegarepoConfig))(
             childConfigContent,
           )
           expect(childConfig.members['grandchild-lib']).toBe(grandchildPath)
@@ -763,7 +760,7 @@ describe('--all nested error reporting', () => {
         yield* initGitRepo(childPath)
         yield* fs.writeFileString(
           EffectPath.ops.join(childPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+          (yield* encodePrettyJson(MegarepoConfig)({
             members: {
               bad: 'not-a-valid-source',
             },
@@ -780,7 +777,7 @@ describe('--all nested error reporting', () => {
         yield* initGitRepo(parentPath)
         yield* fs.writeFileString(
           EffectPath.ops.join(parentPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+          (yield* encodePrettyJson(MegarepoConfig)({
             members: {
               child: childPath,
             },
@@ -806,7 +803,7 @@ describe('--all nested error reporting', () => {
           syncErrors: Schema.Array(SyncErrorItem),
           syncTree: MegarepoSyncTree,
         })
-        const out = yield* Schema.decodeUnknown(Schema.fromJsonString(SyncOutput))(
+        const out = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(SyncOutput))(
           result.stdout.trim(),
         )
 
@@ -878,9 +875,7 @@ const createDiamondDependencyFixture = () =>
     const childAConfig: MegarepoConfig = {
       members: { 'shared-lib': sharedLibPath },
     }
-    const childAConfigContent = yield* Schema.encode(
-      Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-    )(childAConfig)
+    const childAConfigContent = yield* encodePrettyJson(MegarepoConfig)(childAConfig)
     yield* fs.writeFileString(
       EffectPath.ops.join(childAPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
       childAConfigContent + '\n',
@@ -897,9 +892,7 @@ const createDiamondDependencyFixture = () =>
     const childBConfig: MegarepoConfig = {
       members: { 'shared-lib': sharedLibPath },
     }
-    const childBConfigContent = yield* Schema.encode(
-      Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-    )(childBConfig)
+    const childBConfigContent = yield* encodePrettyJson(MegarepoConfig)(childBConfig)
     yield* fs.writeFileString(
       EffectPath.ops.join(childBPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
       childBConfigContent + '\n',
@@ -919,9 +912,7 @@ const createDiamondDependencyFixture = () =>
         'child-b': childBPath,
       },
     }
-    const rootConfigContent = yield* Schema.encode(
-      Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-    )(rootConfig)
+    const rootConfigContent = yield* encodePrettyJson(MegarepoConfig)(rootConfig)
     yield* fs.writeFileString(
       EffectPath.ops.join(rootPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
       rootConfigContent + '\n',
@@ -954,7 +945,7 @@ describe('--all sync deduplication', () => {
           EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
         )
         const rootConfigContent = yield* fs.readFileString(rootConfigPath)
-        const rootConfig = yield* Schema.decodeUnknown(Schema.fromJsonString(MegarepoConfig))(
+        const rootConfig = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(MegarepoConfig))(
           rootConfigContent,
         )
         expect(rootConfig.members['child-a']).toBe(childAPath)
@@ -966,7 +957,7 @@ describe('--all sync deduplication', () => {
           EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
         )
         const childAConfigContent = yield* fs.readFileString(childAConfigPath)
-        const childAConfig = yield* Schema.decodeUnknown(Schema.fromJsonString(MegarepoConfig))(
+        const childAConfig = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(MegarepoConfig))(
           childAConfigContent,
         )
         expect(childAConfig.members['shared-lib']).toBe(sharedLibPath)
@@ -976,7 +967,7 @@ describe('--all sync deduplication', () => {
           EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
         )
         const childBConfigContent = yield* fs.readFileString(childBConfigPath)
-        const childBConfig = yield* Schema.decodeUnknown(Schema.fromJsonString(MegarepoConfig))(
+        const childBConfig = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(MegarepoConfig))(
           childBConfigContent,
         )
         expect(childBConfig.members['shared-lib']).toBe(sharedLibPath)
@@ -1002,7 +993,7 @@ const createPinnedStaleCommitPullFixture = (options?: { readonly useCommitRef?:
     yield* fs.makeDirectory(sourceRepoPath, { recursive: true })
     yield* initGitRepo(sourceRepoPath)
     yield* runGitCommand(sourceRepoPath, 'checkout', '-b', 'main').pipe(
-      Effect.catchAll(() => Effect.void),
+      Effect.catch(() => Effect.void),
     )
     yield* fs.writeFileString(
       EffectPath.ops.join(sourceRepoPath, EffectPath.unsafe.relativeFile('README.md')),
@@ -1020,7 +1011,7 @@ const createPinnedStaleCommitPullFixture = (options?: { readonly useCommitRef?:
     yield* runGitCommand(sourceRepoPath, 'push', '-u', 'origin', 'main')
 
     yield* runGitCommand(sourceRepoPath, 'checkout', '--orphan', 'rewritten-main')
-    yield* runGitCommand(sourceRepoPath, 'rm', '-rf', '.').pipe(Effect.catchAll(() => Effect.void))
+    yield* runGitCommand(sourceRepoPath, 'rm', '-rf', '.').pipe(Effect.catch(() => Effect.void))
     yield* fs.writeFileString(
       EffectPath.ops.join(sourceRepoPath, EffectPath.unsafe.relativeFile('README.md')),
       '# Rewritten history\n',
@@ -1119,7 +1110,7 @@ const createNestedWorkspaceFixtureFromStore = (store: StoreFixtureResult) =>
     yield* initGitRepo(childPath)
     yield* fs.writeFileString(
       EffectPath.ops.join(childPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
-      (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+      (yield* encodePrettyJson(MegarepoConfig)({
         members: {
           shared: 'https://example.com/acme/shared#main',
         },
@@ -1146,7 +1137,7 @@ const createNestedWorkspaceFixtureFromStore = (store: StoreFixtureResult) =>
     yield* initGitRepo(parentPath)
     yield* fs.writeFileString(
       EffectPath.ops.join(parentPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
-      (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+      (yield* encodePrettyJson(MegarepoConfig)({
         members: {
           shared: 'https://example.com/acme/shared#main',
           child: childPath,
@@ -1204,7 +1195,7 @@ const createAliasWorkspaceFixture = () =>
       EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON),
     )
     const parentConfigContent = yield* fs.readFileString(parentConfigPath)
-    const parentConfig = yield* Schema.decodeUnknown(Schema.fromJsonString(MegarepoConfig))(
+    const parentConfig = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(MegarepoConfig))(
       parentConfigContent,
     )
     const updatedConfig = {
@@ -1216,7 +1207,7 @@ const createAliasWorkspaceFixture = () =>
     }
     yield* fs.writeFileString(
       parentConfigPath,
-      (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(updatedConfig)) +
+      (yield* encodePrettyJson(MegarepoConfig)(updatedConfig)) +
         '\n',
     )
 
@@ -1286,7 +1277,7 @@ const createNestedMegarepoLockRefMatchFixture = () =>
     yield* initGitRepo(childPath)
     yield* fs.writeFileString(
       EffectPath.ops.join(childPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
-      (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+      (yield* encodePrettyJson(MegarepoConfig)({
         members: {
           'shared-dev': 'https://example.com/acme/shared#dev',
         },
@@ -1313,7 +1304,7 @@ const createNestedMegarepoLockRefMatchFixture = () =>
     yield* initGitRepo(parentPath)
     yield* fs.writeFileString(
       EffectPath.ops.join(parentPath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
-      (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+      (yield* encodePrettyJson(MegarepoConfig)({
         members: {
           'shared-main': 'https://example.com/acme/shared#main',
           'shared-dev': 'https://example.com/acme/shared#dev',
@@ -1793,9 +1784,7 @@ describe('mr lock', () => {
               effect: 'effect-ts/effect',
             },
           }
-          const configContent = yield* Schema.encode(
-            Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-          )(config)
+          const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
           yield* fs.writeFileString(
             EffectPath.ops.join(
               workspacePath,
@@ -1875,7 +1864,7 @@ describe('mr lock', () => {
           )
           yield* fs.writeFileString(
             configPath,
-            (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+            (yield* encodePrettyJson(MegarepoConfig)(
               initialConfig,
             )) + '\n',
           )
@@ -1911,7 +1900,7 @@ describe('mr lock', () => {
           }
           yield* fs.writeFileString(
             configPath,
-            (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+            (yield* encodePrettyJson(MegarepoConfig)(
               updatedConfig,
             )) + '\n',
           )
@@ -1990,7 +1979,7 @@ describe('mr lock', () => {
           )
           yield* fs.writeFileString(
             configPath,
-            (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+            (yield* encodePrettyJson(MegarepoConfig)({
               members: { 'my-lib': mainRepoPath },
             })) + '\n',
           )
@@ -2008,7 +1997,7 @@ describe('mr lock', () => {
           // Update config to point to feature branch
           yield* fs.writeFileString(
             configPath,
-            (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+            (yield* encodePrettyJson(MegarepoConfig)({
               members: { 'my-lib': featureRepoPath },
             })) + '\n',
           )
@@ -2220,7 +2209,7 @@ describe('mr lock', () => {
           )
           yield* fs.writeFileString(
             configPath,
-            (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+            (yield* encodePrettyJson(MegarepoConfig)({
               members: { 'my-lib': mainRepoPath },
             })) + '\n',
           )
@@ -2238,7 +2227,7 @@ describe('mr lock', () => {
           // Update config
           yield* fs.writeFileString(
             configPath,
-            (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))({
+            (yield* encodePrettyJson(MegarepoConfig)({
               members: { 'my-lib': featureRepoPath },
             })) + '\n',
           )
@@ -2509,7 +2498,7 @@ describe('mr fetch', () => {
           yield* initGitRepo(sourceRepoPath)
           // Force branch name to 'main' regardless of git config default
           yield* runGitCommand(sourceRepoPath, 'checkout', '-b', 'main').pipe(
-            Effect.catchAll(() => Effect.void),
+            Effect.catch(() => Effect.void),
           )
           yield* fs.writeFileString(
             EffectPath.ops.join(sourceRepoPath, EffectPath.unsafe.relativeFile('README.md')),
@@ -2652,9 +2641,7 @@ describe('sync status types', () => {
             'new-lib': localRepoPath,
           },
         }
-        const configContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(config)
+        const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
         yield* fs.writeFileString(
           EffectPath.ops.join(workspacePath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
           configContent + '\n',
@@ -2711,9 +2698,7 @@ describe('sync error handling', () => {
             'non-existent-repo': pathToFileURL(missingRemotePath).href,
           },
         }
-        const configContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(config)
+        const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
         yield* fs.writeFileString(
           EffectPath.ops.join(workspacePath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
           configContent + '\n',
@@ -2803,9 +2788,7 @@ describe('sync member filtering', () => {
               repo2: repo2Path,
             },
           }
-          const configContent = yield* Schema.encode(
-            Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-          )(config)
+          const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
           yield* fs.writeFileString(
             EffectPath.ops.join(
               workspacePath,
@@ -2874,9 +2857,7 @@ describe('sync member filtering', () => {
               repo2: repo2Path,
             },
           }
-          const configContent = yield* Schema.encode(
-            Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-          )(config)
+          const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
           yield* fs.writeFileString(
             EffectPath.ops.join(
               workspacePath,
@@ -2928,9 +2909,7 @@ describe('sync member filtering', () => {
               repo1: 'owner/repo1',
             },
           }
-          const configContent = yield* Schema.encode(
-            Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-          )(config)
+          const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
           yield* fs.writeFileString(
             EffectPath.ops.join(
               workspacePath,
@@ -2954,7 +2933,7 @@ describe('sync member filtering', () => {
           expect(Exit.isFailure(result.exit)).toBe(true)
           if (Exit.isFailure(result.exit) === true) {
             const cause = result.exit.cause
-            const failureMessages = Chunk.toReadonlyArray(Cause.failures(cause))
+            const failureMessages = cause.reasons.filter(Cause.isFailReason).map((reason) => reason.error)
               .map((error: unknown) => String(error))
               .join('\n')
             expect(failureMessages.toLowerCase()).toContain('mutually exclusive')
@@ -3027,9 +3006,7 @@ describe('sync worktree ref mismatch detection', () => {
             'test-repo': 'https://example.com/org/test-repo#main',
           },
         }
-        const configContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(config)
+        const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
         yield* fs.writeFileString(
           EffectPath.ops.join(workspacePath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
           configContent + '\n',
@@ -3133,9 +3110,7 @@ describe('sync worktree ref mismatch detection', () => {
             'test-repo': 'https://example.com/org/test-repo#main',
           },
         }
-        const configContent = yield* Schema.encode(
-          Schema.fromJsonString(MegarepoConfig, { space: 2 }),
-        )(config)
+        const configContent = yield* encodePrettyJson(MegarepoConfig)(config)
         yield* fs.writeFileString(
           EffectPath.ops.join(workspacePath, EffectPath.unsafe.relativeFile(CONFIG_FILE_NAME_JSON)),
           configContent + '\n',
@@ -3250,7 +3225,7 @@ describe('sync member removal detection', () => {
         }
         yield* fs.writeFileString(
           configPath,
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+          (yield* encodePrettyJson(MegarepoConfig)(
             initialConfig,
           )) + '\n',
         )
@@ -3283,7 +3258,7 @@ describe('sync member removal detection', () => {
         }
         yield* fs.writeFileString(
           configPath,
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+          (yield* encodePrettyJson(MegarepoConfig)(
             updatedConfig,
           )) + '\n',
         )
@@ -3360,7 +3335,7 @@ describe('sync member removal detection', () => {
         }
         yield* fs.writeFileString(
           configPath,
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+          (yield* encodePrettyJson(MegarepoConfig)(
             initialConfig,
           )) + '\n',
         )
@@ -3380,7 +3355,7 @@ describe('sync member removal detection', () => {
         }
         yield* fs.writeFileString(
           configPath,
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+          (yield* encodePrettyJson(MegarepoConfig)(
             updatedConfig,
           )) + '\n',
         )
@@ -3456,7 +3431,7 @@ describe('sync member removal detection', () => {
         }
         yield* fs.writeFileString(
           configPath,
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(config)) +
+          (yield* encodePrettyJson(MegarepoConfig)(config)) +
             '\n',
         )
         yield* addCommit({
@@ -3527,7 +3502,7 @@ describe('sync member removal detection', () => {
         }
         yield* fs.writeFileString(
           configPath,
-          (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(config)) +
+          (yield* encodePrettyJson(MegarepoConfig)(config)) +
             '\n',
         )
         yield* addCommit({
diff --git a/packages/@overeng/megarepo/src/lib/config.ts b/packages/@overeng/megarepo/src/lib/config.ts
index 1ec0eab2b7..e1fc58e3f0 100644
--- a/packages/@overeng/megarepo/src/lib/config.ts
+++ b/packages/@overeng/megarepo/src/lib/config.ts
@@ -14,7 +14,7 @@
  */
 
 import { Effect, JsonSchema, Option, Schema } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 
 import {
   EffectPath,
@@ -261,7 +261,7 @@ export const readMegarepoConfig = (megarepoRoot: AbsoluteDirPath) =>
       const content = yield* fs.readFileString(configPath)
       const format: ConfigFormat = fileName.endsWith('.kdl') === true ? 'kdl' : 'json'
 
-      const config = yield* Schema.decodeUnknown(
+      const config = yield* Schema.decodeUnknownEffect(
         format === 'kdl' ? MegarepoConfigFromKdl : Schema.fromJsonString(MegarepoConfig),
       )(content)
 
@@ -288,8 +288,8 @@ export const writeMegarepoConfig = ({
 
     const content =
       format === 'kdl'
-        ? yield* Schema.encode(MegarepoConfigFromKdl)(config)
-        : (yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(config)) + '\n'
+        ? yield* Schema.encodeEffect(MegarepoConfigFromKdl)(config)
+        : JSON.stringify(yield* Schema.encodeEffect(MegarepoConfig)(config), null, 2) + '\n'
 
     yield* fs.writeFileString(configPath, content)
   })
diff --git a/packages/@overeng/megarepo/src/lib/generators/schema.ts b/packages/@overeng/megarepo/src/lib/generators/schema.ts
index 8ef8689e68..02112c91e2 100644
--- a/packages/@overeng/megarepo/src/lib/generators/schema.ts
+++ b/packages/@overeng/megarepo/src/lib/generators/schema.ts
@@ -5,7 +5,7 @@
  * Output: schema/megarepo.schema.json in the specified location.
  */
 
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect } from 'effect'
 
 import {
diff --git a/packages/@overeng/megarepo/src/lib/generators/vscode.ts b/packages/@overeng/megarepo/src/lib/generators/vscode.ts
index 6e3d278284..7df846a266 100644
--- a/packages/@overeng/megarepo/src/lib/generators/vscode.ts
+++ b/packages/@overeng/megarepo/src/lib/generators/vscode.ts
@@ -5,7 +5,7 @@
  * Output: .vscode/megarepo.code-workspace in the megarepo root.
  */
 
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect } from 'effect'
 
 import {
diff --git a/packages/@overeng/megarepo/src/lib/git-memory.integration.test.ts b/packages/@overeng/megarepo/src/lib/git-memory.integration.test.ts
index cdcc1eba16..4e7336b0cb 100644
--- a/packages/@overeng/megarepo/src/lib/git-memory.integration.test.ts
+++ b/packages/@overeng/megarepo/src/lib/git-memory.integration.test.ts
@@ -24,7 +24,7 @@ import { fileURLToPath } from 'node:url'
 
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
-import { ChildProcess as Command } from 'effect/unstable/process'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
 import { Effect, Schema } from 'effect'
 import { expect } from 'vitest'
 
@@ -82,14 +82,14 @@ describe('git memory regression', () => {
         // only — it must stay generous because bun/JSC reserves a large virtual
         // address space regardless of resident set; the assertion below (on
         // resident growth) is the real bound, not this limit.
-        const probe = Command.make(
-          'bash',
+        const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+        const probe = Command.make('bash', [
           '-c',
           'ulimit -v 16777216; exec bun "$0" "$1"',
           probeScript,
           worktreePath,
-        )
-        const stdout = yield* Command.string(probe)
+        ])
+        const stdout = yield* spawner.string(probe)
         const result = decodeProbe(stdout.trim())
 
         const growthKb = result.vmHwmKb - result.rssStartKb
diff --git a/packages/@overeng/megarepo/src/lib/git-streaming-parsers.integration.test.ts b/packages/@overeng/megarepo/src/lib/git-streaming-parsers.integration.test.ts
index 529ef3b13c..9334b152ae 100644
--- a/packages/@overeng/megarepo/src/lib/git-streaming-parsers.integration.test.ts
+++ b/packages/@overeng/megarepo/src/lib/git-streaming-parsers.integration.test.ts
@@ -11,8 +11,8 @@
  * helper is proven separately by `git-memory.integration.test.ts`.
  */
 
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
 import { Effect, Option } from 'effect'
@@ -24,8 +24,9 @@ import * as Git from './git.ts'
 
 const git = (cwd: string, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...args).pipe(Command.workingDirectory(cwd))
-    return (yield* Command.string(command)).trim()
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', args, { cwd })
+    return (yield* spawner.string(command)).trim()
   })
 
 const makeRepoDir = Effect.gen(function* () {
diff --git a/packages/@overeng/megarepo/src/lib/git-timeout.integration.test.ts b/packages/@overeng/megarepo/src/lib/git-timeout.integration.test.ts
index 34200b3040..878bee089b 100644
--- a/packages/@overeng/megarepo/src/lib/git-timeout.integration.test.ts
+++ b/packages/@overeng/megarepo/src/lib/git-timeout.integration.test.ts
@@ -14,8 +14,8 @@
  * used to break for large members.
  */
 
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
 import { Effect } from 'effect'
@@ -31,8 +31,9 @@ const GIT_USER = ['-c', 'user.email=test@example.com', '-c', 'user.name=Test Use
 /** Run git in `cwd`, returning trimmed stdout (fixture setup only). */
 const git = (cwd: string, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...GIT_USER, ...args).pipe(Command.workingDirectory(cwd))
-    return (yield* Command.string(command)).trim()
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', [...GIT_USER, ...args], { cwd })
+    return (yield* spawner.string(command)).trim()
   })
 
 /**
diff --git a/packages/@overeng/megarepo/src/lib/git.ts b/packages/@overeng/megarepo/src/lib/git.ts
index 6db5f16ffd..610f41fcf8 100644
--- a/packages/@overeng/megarepo/src/lib/git.ts
+++ b/packages/@overeng/megarepo/src/lib/git.ts
@@ -4,7 +4,7 @@
  * Provides Effect-wrapped git operations for cloning, fetching, and managing worktrees.
  */
 
-import { ChildProcess as Command } from 'effect/unstable/process'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
 import { Cause, Chunk, Duration, Effect, Option, Schedule, Sink, Stream } from 'effect'
 
 import * as Observability from './observability.ts'
@@ -215,23 +215,24 @@ const decodeChunks = (chunks: Chunk.Chunk<Uint8Array>): string => {
  */
 const startGitProcess = ({ args, cwd }: { args: ReadonlyArray<string>; cwd?: string }) =>
   Effect.gen(function* () {
-    const cmd = Command.make('git', ...args).pipe(
-      cwd !== undefined ? Command.workingDirectory(cwd) : (x) => x,
-      Command.stderr('pipe'),
-      Command.stdout('pipe'),
-    )
+    const cmd = Command.make('git', args, {
+      ...(cwd !== undefined ? { cwd } : {}),
+      stderr: 'pipe',
+      stdout: 'pipe',
+    })
 
-    const process = yield* Command.start(cmd)
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const process = yield* spawner.spawn(cmd)
     yield* Effect.addFinalizer((exit) =>
       Effect.gen(function* () {
-        if (exit._tag !== 'Failure' || Cause.isInterruptedOnly(exit.cause) === false) {
+        if (exit._tag !== 'Failure' || Cause.hasInterruptsOnly(exit.cause) === false) {
           return
         }
 
         const isRunning = yield* process.isRunning.pipe(Effect.orElseSucceed(() => false))
         if (isRunning === false) return
 
-        yield* process.kill('SIGKILL').pipe(Effect.catchAll(() => Effect.void))
+        yield* process.kill('SIGKILL').pipe(Effect.catch(() => Effect.void))
       }),
     )
     return process
diff --git a/packages/@overeng/megarepo/src/lib/json-wire-baseline.test.ts b/packages/@overeng/megarepo/src/lib/json-wire-baseline.test.ts
index 5345d5a303..9af50e1bef 100644
--- a/packages/@overeng/megarepo/src/lib/json-wire-baseline.test.ts
+++ b/packages/@overeng/megarepo/src/lib/json-wire-baseline.test.ts
@@ -3,10 +3,11 @@ import { describe, expect, it } from 'vitest'
 
 import { StoreState } from '../cli/renderers/StoreOutput/schema.ts'
 import { MegarepoConfig } from './config.ts'
+import { encodePrettyJsonSync } from './json.ts'
 import { LockFile } from './lock.ts'
 
 const encodeJson = <A, I>(schema: Schema.Schema<A, I, never>, value: A): string =>
-  Schema.encodeSync(Schema.fromJsonString(schema, { space: 2 }))(value)
+  encodePrettyJsonSync(schema, value)
 
 const decodeJson = <A, I>(schema: Schema.Schema<A, I, never>, encoded: string): A =>
   Schema.decodeUnknownSync(Schema.fromJsonString(schema))(encoded)
diff --git a/packages/@overeng/megarepo/src/lib/json.ts b/packages/@overeng/megarepo/src/lib/json.ts
new file mode 100644
index 0000000000..571a536ad7
--- /dev/null
+++ b/packages/@overeng/megarepo/src/lib/json.ts
@@ -0,0 +1,13 @@
+import { Effect, Schema } from 'effect'
+
+export const encodePrettyJson =
+  <A, I>(schema: Schema.ConstraintCodec<A, I, never, never>) =>
+  (value: A) =>
+    Schema.encodeEffect(schema)(value).pipe(
+    Effect.map((encoded) => JSON.stringify(encoded, null, 2)),
+    )
+
+export const encodePrettyJsonSync = <A, I>(
+  schema: Schema.ConstraintCodec<A, I, never, never>,
+  value: A,
+): string => JSON.stringify(Schema.encodeSync(schema)(value), null, 2)
diff --git a/packages/@overeng/megarepo/src/lib/lock.ts b/packages/@overeng/megarepo/src/lib/lock.ts
index 7ed3044b0e..45b1e263e4 100644
--- a/packages/@overeng/megarepo/src/lib/lock.ts
+++ b/packages/@overeng/megarepo/src/lib/lock.ts
@@ -9,13 +9,15 @@
  * Note: Local path sources are NOT in the lock file - they're already local.
  */
 
-import type { Error as PlatformError } from 'effect'
-import type { ParseResult } from 'effect'
+import * as PlatformError from 'effect/PlatformError'
+import * as SchemaError from 'effect/SchemaError'
 import { Effect, Option, Schema } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 
 import type { AbsoluteFilePath } from '@overeng/effect-path'
 
+import { encodePrettyJson } from './json.ts'
+
 // =============================================================================
 // Lock File Schema
 // =============================================================================
@@ -68,7 +70,7 @@ export const readLockFile = (
   lockPath: AbsoluteFilePath,
 ): Effect.Effect<
   Option.Option<LockFile>,
-  PlatformError.PlatformError | ParseResult.ParseError,
+  PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
@@ -80,7 +82,7 @@ export const readLockFile = (
     }
 
     const content = yield* fs.readFileString(lockPath)
-    const parsed = yield* Schema.decodeUnknown(Schema.fromJsonString(LockFile))(content)
+    const parsed = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(LockFile))(content)
     return Option.some(parsed)
   })
 
@@ -95,12 +97,12 @@ export const writeLockFile = ({
   lockFile: LockFile
 }): Effect.Effect<
   void,
-  PlatformError.PlatformError | ParseResult.ParseError,
+  PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
     const fs = yield* FileSystem.FileSystem
-    const content = yield* Schema.encode(Schema.fromJsonString(LockFile, { space: 2 }))(lockFile)
+    const content = yield* encodePrettyJson(LockFile)(lockFile)
     yield* fs.writeFileString(lockPath, content + '\n')
   })
 
diff --git a/packages/@overeng/megarepo/src/lib/megarepo-traversal.ts b/packages/@overeng/megarepo/src/lib/megarepo-traversal.ts
index e4873b3fe4..cfeb0a683e 100644
--- a/packages/@overeng/megarepo/src/lib/megarepo-traversal.ts
+++ b/packages/@overeng/megarepo/src/lib/megarepo-traversal.ts
@@ -6,9 +6,10 @@
  * Raw traversal paths can grow forever in symlink cycles.
  */
 
-import type { Error as PlatformError } from 'effect'
-import { Effect, Ref, Schema, type ParseResult } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import { Effect, Ref, Schema } from 'effect'
+import * as SchemaError from 'effect/SchemaError'
+import * as FileSystem from 'effect/FileSystem'
 
 import type { AbsoluteDirPath } from '@overeng/effect-path'
 
@@ -64,7 +65,7 @@ export interface MegarepoTraversal {
     readonly depth: number
   }) => Effect.Effect<
     MegarepoTraversalEnterResult,
-    PlatformError.PlatformError | ParseResult.ParseError,
+    PlatformError.PlatformError | SchemaError.SchemaError,
     FileSystem.FileSystem
   >
   readonly stats: Effect.Effect<MegarepoTraversalStats>
@@ -79,7 +80,7 @@ const canonicalizeRoot = Effect.fn('megarepo/traversal/canonicalize-root')(funct
     Effect.map(stripTrailingSlashesPreservingRoot),
     Effect.orElseSucceed(() => normalizedRoot),
   )
-  const key = yield* Schema.decodeUnknown(MegarepoTraversalNodeKey)(resolvedRoot)
+  const key = yield* Schema.decodeUnknownEffect(MegarepoTraversalNodeKey)(resolvedRoot)
   return { key, resolvedRoot }
 })
 
diff --git a/packages/@overeng/megarepo/src/lib/nix-lock/input-discovery.ts b/packages/@overeng/megarepo/src/lib/nix-lock/input-discovery.ts
index d5e8a5856c..14747591a7 100644
--- a/packages/@overeng/megarepo/src/lib/nix-lock/input-discovery.ts
+++ b/packages/@overeng/megarepo/src/lib/nix-lock/input-discovery.ts
@@ -5,8 +5,8 @@
  * which megarepo members are referenced as inputs by other members.
  */
 
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
diff --git a/packages/@overeng/megarepo/src/lib/nix-lock/mod.ts b/packages/@overeng/megarepo/src/lib/nix-lock/mod.ts
index b647fac0e1..ba84d30d13 100644
--- a/packages/@overeng/megarepo/src/lib/nix-lock/mod.ts
+++ b/packages/@overeng/megarepo/src/lib/nix-lock/mod.ts
@@ -8,17 +8,19 @@
  * source of truth for dependency versions.
  */
 
-import type { Error as PlatformError } from 'effect'
-import { Effect, Option, Schema, type ParseResult } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import { Effect, Option, Schema } from 'effect'
+import * as SchemaError from 'effect/SchemaError'
+import * as FileSystem from 'effect/FileSystem'
 import {
   ChildProcess as Command,
-  type ChildProcessSpawner as CommandExecutor,
+  ChildProcessSpawner as CommandExecutor,
 } from 'effect/unstable/process'
 
 import { EffectPath, type AbsoluteDirPath, type AbsoluteFilePath } from '@overeng/effect-path'
 
 import { findConfigPath, getMemberPath, type MegarepoConfig } from '../config.ts'
+import { encodePrettyJson, encodePrettyJsonSync } from '../json.ts'
 import {
   LOCK_FILE_NAME,
   readLockFile,
@@ -127,18 +129,12 @@ const DEVENV_LOCK = 'devenv.lock'
 const MEGAREPO_LOCK = LOCK_FILE_NAME
 
 /** Schema for raw flake lock JSON (used to preserve key order during manipulation) */
-const RawFlakeLockJson = Schema.fromJsonString(
-  Schema.mutable(
-    Schema.Struct({
-      nodes: Schema.mutable(
-        Schema.Record(Schema.String, Schema.mutable(Schema.Record(Schema.String, Schema.Unknown))),
-      ),
-      root: Schema.String,
-      version: Schema.Number,
-    }),
-  ),
-  { space: 2 },
-)
+const RawFlakeLock = Schema.Struct({
+  nodes: Schema.Record(Schema.String, Schema.Record(Schema.String, Schema.Unknown)),
+  root: Schema.String,
+  version: Schema.Number,
+})
+const RawFlakeLockJson = Schema.fromJsonString(RawFlakeLock)
 
 /**
  * Schema for an opaque JSON object (devenv.lock / flake.lock) whose nodes are
@@ -146,14 +142,12 @@ const RawFlakeLockJson = Schema.fromJsonString(
  * with 2-space indentation, matching the prior `JSON.stringify(value, null, 2)`
  * output byte-for-byte.
  */
-const RawLockJson = Schema.fromJsonString(
-  Schema.mutable(Schema.Record(Schema.String, Schema.Unknown)),
-  { space: 2 },
-)
+const RawLock = Schema.Record(Schema.String, Schema.Unknown)
+const RawLockJson = Schema.fromJsonString(RawLock)
 
 /** Encode a manipulated lock object back to its 2-space JSON file content (with trailing newline). */
 const encodeRawLockJson = (value: Record<string, unknown>): string =>
-  Schema.encodeSync(RawLockJson)(value) + '\n'
+  encodePrettyJsonSync(RawLock, value) + '\n'
 
 // =============================================================================
 // Nix Metadata Fetching
@@ -198,14 +192,15 @@ export const fetchNixFlakeMetadata = ({
   rev: string
 }): Effect.Effect<
   NixFlakeMetadata,
-  PlatformError.PlatformError | ParseResult.ParseError | NixFlakeMetadataError,
-  CommandExecutor.CommandExecutor
+  PlatformError.PlatformError | SchemaError.SchemaError | NixFlakeMetadataError,
+  CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
+    const executor = yield* CommandExecutor.ChildProcessSpawner
     const flakeRef = `github:${owner}/${repo}/${rev}`
 
-    const command = Command.make('nix', 'flake', 'prefetch', flakeRef, '--json')
-    const result = yield* Command.string(command)
+    const command = Command.make('nix', ['flake', 'prefetch', flakeRef, '--json'])
+    const result = yield* executor.string(command)
 
     // Check for empty output - this typically means the command failed.
     // Nix outputs errors to stderr and returns empty stdout with non-zero exit code.
@@ -220,7 +215,7 @@ export const fetchNixFlakeMetadata = ({
     }
 
     // Attempt to parse the JSON output
-    const parsed = yield* Schema.decodeUnknown(NixFlakePrefetchOutput)(result).pipe(
+    const parsed = yield* Schema.decodeUnknownEffect(NixFlakePrefetchOutput)(result).pipe(
       Effect.mapError((parseError) => {
         // Check if output looks like a nix error message (shouldn't normally happen
         // since nix errors go to stderr, but handle defensively)
@@ -340,15 +335,15 @@ const syncSingleLockFile = ({
   megarepoMembers: Record<string, LockedMember>
 }): Effect.Effect<
   NixLockSyncFileResult,
-  PlatformError.PlatformError | ParseResult.ParseError,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor
+  PlatformError.PlatformError | SchemaError.SchemaError,
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const fs = yield* FileSystem.FileSystem
 
     // Read and parse the lock file (Schema.parseJson handles both parsing and validation)
     const content = yield* fs.readFileString(lockPath)
-    const rawJson = yield* Schema.decodeUnknown(RawFlakeLockJson)(content)
+    const rawJson = yield* Schema.decodeUnknownEffect(RawFlakeLockJson)(content)
 
     // First pass: collect all nodes that need metadata fetching
     const nodesToUpdate: NodeUpdateInfo[] = []
@@ -498,7 +493,7 @@ const syncSingleLockFile = ({
 
     // Write updated lock file if any changes were made
     if (updatedInputs.length > 0 || schemeNormalized === true) {
-      const updatedContent = yield* Schema.encode(RawFlakeLockJson)(rawJson)
+      const updatedContent = yield* encodePrettyJson(RawFlakeLock)(rawJson)
       yield* fs.writeFileString(lockPath, updatedContent + '\n')
     }
 
@@ -526,7 +521,7 @@ const syncNestedMegarepoLockFile = ({
   megarepoMembers: Record<string, LockedMember>
 }): Effect.Effect<
   NixLockSyncFileResult,
-  PlatformError.PlatformError | ParseResult.ParseError,
+  PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
@@ -776,9 +771,9 @@ const validateSharedInputSource = ({
     }
 
     const sourceContent = yield* fs.readFileString(sourceLockPath)
-    const sourceJson = yield* Schema.decodeUnknown(RawLockJson)(sourceContent).pipe(
+    const sourceJson = yield* Schema.decodeUnknownEffect(RawLockJson)(sourceContent).pipe(
       Effect.catchTag(
-        'ParseError',
+        'SchemaError',
         () =>
           new SharedInputSourceError({
             message: `Source member '${sourceMemberName}' has invalid devenv.lock (not valid JSON)`,
@@ -1219,7 +1214,7 @@ export const syncNixLocks = Effect.fn('megarepo/nix-lock/sync')((options: NixLoc
               lockType: 'flake.lock',
               megarepoMembers,
             }).pipe(
-              Effect.catchTag('ParseError', (e) =>
+              Effect.catchTag('SchemaError', (e) =>
                 Effect.gen(function* () {
                   yield* Effect.logWarning(`Failed to parse ${flakeLockPath}: ${e.message}`)
                   return {
@@ -1247,7 +1242,7 @@ export const syncNixLocks = Effect.fn('megarepo/nix-lock/sync')((options: NixLoc
               lockType: 'devenv.lock',
               megarepoMembers,
             }).pipe(
-              Effect.catchTag('ParseError', (e) =>
+              Effect.catchTag('SchemaError', (e) =>
                 Effect.gen(function* () {
                   yield* Effect.logWarning(`Failed to parse ${devenvLockPath}: ${e.message}`)
                   return {
@@ -1277,7 +1272,7 @@ export const syncNixLocks = Effect.fn('megarepo/nix-lock/sync')((options: NixLoc
                 lockPath: nestedMegarepoLockPath,
                 megarepoMembers,
               }).pipe(
-                Effect.catchTag('ParseError', (e) =>
+                Effect.catchTag('SchemaError', (e) =>
                   Effect.gen(function* () {
                     yield* Effect.logWarning(
                       `Failed to parse ${nestedMegarepoLockPath}: ${e.message}`,
diff --git a/packages/@overeng/megarepo/src/lib/observability.ts b/packages/@overeng/megarepo/src/lib/observability.ts
index e79f498974..13abd242b2 100644
--- a/packages/@overeng/megarepo/src/lib/observability.ts
+++ b/packages/@overeng/megarepo/src/lib/observability.ts
@@ -85,7 +85,7 @@ const trustOtelContract = <A, E, R>(
   effect: Effect.Effect<A, E | OtelAttrEncodeError, R>,
 ): Effect.Effect<A, E, R> =>
   effect.pipe(
-    Effect.catchAll((error) =>
+    Effect.catch((error) =>
       typeof error === 'object' &&
       error !== null &&
       '_tag' in error &&
diff --git a/packages/@overeng/megarepo/src/lib/source-policy.ts b/packages/@overeng/megarepo/src/lib/source-policy.ts
index 4407e52082..460953031f 100644
--- a/packages/@overeng/megarepo/src/lib/source-policy.ts
+++ b/packages/@overeng/megarepo/src/lib/source-policy.ts
@@ -1,5 +1,5 @@
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Option } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
diff --git a/packages/@overeng/megarepo/src/lib/source-policy.unit.test.ts b/packages/@overeng/megarepo/src/lib/source-policy.unit.test.ts
index 21db9af33a..548a950a07 100644
--- a/packages/@overeng/megarepo/src/lib/source-policy.unit.test.ts
+++ b/packages/@overeng/megarepo/src/lib/source-policy.unit.test.ts
@@ -1,4 +1,4 @@
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { Effect, type Scope } from 'effect'
 import { describe, expect, it } from 'vitest'
diff --git a/packages/@overeng/megarepo/src/lib/store-archive.integration.test.ts b/packages/@overeng/megarepo/src/lib/store-archive.integration.test.ts
index 02413cc2ef..a92462c377 100644
--- a/packages/@overeng/megarepo/src/lib/store-archive.integration.test.ts
+++ b/packages/@overeng/megarepo/src/lib/store-archive.integration.test.ts
@@ -14,8 +14,8 @@
  * contain `-`/`--`/`/`; only a trailing valid ISO8601 instant is a timestamp).
  */
 
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
 import { Effect, Option } from 'effect'
@@ -34,8 +34,9 @@ import { archiveWorktree, parseArchiveDirName, reapArchive, scanArchives } from
 
 const git = (cwd: string, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...args).pipe(Command.workingDirectory(cwd))
-    return (yield* Command.string(command)).trim()
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', args, { cwd })
+    return (yield* spawner.string(command)).trim()
   })
 
 /** `<store>/github.com/<owner>/<repo>/` repo root for a fixture repo key. */
diff --git a/packages/@overeng/megarepo/src/lib/store-archive.ts b/packages/@overeng/megarepo/src/lib/store-archive.ts
index 7aa291180c..b92fed3f81 100644
--- a/packages/@overeng/megarepo/src/lib/store-archive.ts
+++ b/packages/@overeng/megarepo/src/lib/store-archive.ts
@@ -32,8 +32,8 @@
  */
 
 import type { ChildProcessSpawner as CommandExecutor } from 'effect/unstable/process'
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Option } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
@@ -164,7 +164,7 @@ export const archiveWorktree = (args: {
 }): Effect.Effect<
   ArchiveOutcome,
   Git.GitCommandError | PlatformError.PlatformError,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const fs = yield* FileSystem.FileSystem
@@ -202,7 +202,7 @@ export const archiveWorktree = (args: {
       Effect.flatMap(() =>
         Git.deleteBranch({ repoPath: args.bareRepoPath, branch: args.branch, force: true }),
       ),
-      Effect.catchAll((error) =>
+      Effect.catch((error) =>
         Effect.sync(() => {
           warnings.push(
             `branch '${args.branch}' could not be freed (re-add may fail until cleaned up): ${error.message}`,
@@ -221,7 +221,7 @@ export const archiveWorktree = (args: {
     yield* fs.readFileString(readmePath).pipe(
       Effect.orElseSucceed(() => ''),
       Effect.flatMap((existing) => writeFileAtomic({ path: readmePath, content: existing + line })),
-      Effect.catchAll((error) =>
+      Effect.catch((error) =>
         Effect.sync(() => {
           warnings.push(`archive README metadata not recorded: ${error.message}`)
         }),
@@ -260,7 +260,7 @@ export const archiveRefMismatchWorktree = (args: {
 }): Effect.Effect<
   ArchiveOutcome,
   Git.GitCommandError | PlatformError.PlatformError,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const fs = yield* FileSystem.FileSystem
@@ -285,7 +285,7 @@ export const archiveRefMismatchWorktree = (args: {
     const warnings: Array<string> = []
 
     yield* Git.detachWorktreeHead({ worktreePath: destPath }).pipe(
-      Effect.catchAll((error) =>
+      Effect.catch((error) =>
         Effect.sync(() => {
           warnings.push(
             `archived worktree HEAD could not be detached (branch refs were preserved): ${error.message}`,
@@ -302,7 +302,7 @@ export const archiveRefMismatchWorktree = (args: {
     yield* fs.readFileString(readmePath).pipe(
       Effect.orElseSucceed(() => ''),
       Effect.flatMap((existing) => writeFileAtomic({ path: readmePath, content: existing + line })),
-      Effect.catchAll((error) =>
+      Effect.catch((error) =>
         Effect.sync(() => {
           warnings.push(`archive README metadata not recorded: ${error.message}`)
         }),
@@ -332,7 +332,7 @@ export const scanArchives = (args: {
 }): Effect.Effect<
   ReadonlyArray<ArchiveEntry>,
   Git.GitCommandError | PlatformError.PlatformError,
-  CommandExecutor.CommandExecutor
+  CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const archiveDir = archiveDirPath(args.repoRoot)
@@ -383,7 +383,7 @@ export const reapArchive = (args: {
 }): Effect.Effect<
   void,
   Git.GitCommandError | PlatformError.PlatformError,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const fs = yield* FileSystem.FileSystem
diff --git a/packages/@overeng/megarepo/src/lib/store-fs-atomic.ts b/packages/@overeng/megarepo/src/lib/store-fs-atomic.ts
index 61baea22bc..33d7b5e896 100644
--- a/packages/@overeng/megarepo/src/lib/store-fs-atomic.ts
+++ b/packages/@overeng/megarepo/src/lib/store-fs-atomic.ts
@@ -10,8 +10,8 @@
 
 import { randomBytes } from 'node:crypto'
 
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect } from 'effect'
 
 import { EffectPath, type AbsoluteFilePath } from '@overeng/effect-path'
@@ -48,10 +48,10 @@ export const writeFileAtomic = ({
     const tempPath = tempPathFor(path)
     yield* fs
       .writeFileString(tempPath, content)
-      .pipe(Effect.tapError(() => fs.remove(tempPath).pipe(Effect.catchAll(() => Effect.void))))
+      .pipe(Effect.tapError(() => fs.remove(tempPath).pipe(Effect.catch(() => Effect.void))))
     yield* fs
       .rename(tempPath, path)
-      .pipe(Effect.tapError(() => fs.remove(tempPath).pipe(Effect.catchAll(() => Effect.void))))
+      .pipe(Effect.tapError(() => fs.remove(tempPath).pipe(Effect.catch(() => Effect.void))))
   }).pipe(
     Observability.withLabelSpan({
       name: 'megarepo/store/fs/write-atomic',
diff --git a/packages/@overeng/megarepo/src/lib/store-fs-atomic.unit.test.ts b/packages/@overeng/megarepo/src/lib/store-fs-atomic.unit.test.ts
index 5a26603123..2353fa66d2 100644
--- a/packages/@overeng/megarepo/src/lib/store-fs-atomic.unit.test.ts
+++ b/packages/@overeng/megarepo/src/lib/store-fs-atomic.unit.test.ts
@@ -7,7 +7,7 @@
  *   no `.tmp-*` sibling lingering as garbage (the `tapError` cleanup branch).
  */
 
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
 import { Effect } from 'effect'
diff --git a/packages/@overeng/megarepo/src/lib/store-gc-config.ts b/packages/@overeng/megarepo/src/lib/store-gc-config.ts
index 8c1a008986..fad94d8fcb 100644
--- a/packages/@overeng/megarepo/src/lib/store-gc-config.ts
+++ b/packages/@overeng/megarepo/src/lib/store-gc-config.ts
@@ -7,8 +7,8 @@
  * unknown/invalid files fall back to the defaults (never fail the gc path).
  */
 
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Schema } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
@@ -84,7 +84,7 @@ export const loadStoreGcConfig = ({
     const path = gcConfigPath(storeBasePath)
     const override = yield* fs.readFileString(path).pipe(
       Effect.flatMap((content) =>
-        Schema.decodeUnknown(Schema.fromJsonString(StoreGcConfigOverride))(content),
+        Schema.decodeUnknownEffect(Schema.fromJsonString(StoreGcConfigOverride))(content),
       ),
       Effect.orElseSucceed(() => ({}) as StoreGcConfigOverride),
     )
diff --git a/packages/@overeng/megarepo/src/lib/store-gc-config.unit.test.ts b/packages/@overeng/megarepo/src/lib/store-gc-config.unit.test.ts
index 2c81a589db..7b3be942ba 100644
--- a/packages/@overeng/megarepo/src/lib/store-gc-config.unit.test.ts
+++ b/packages/@overeng/megarepo/src/lib/store-gc-config.unit.test.ts
@@ -1,4 +1,4 @@
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { it as effectIt } from '@effect/vitest'
 import { Effect } from 'effect'
diff --git a/packages/@overeng/megarepo/src/lib/store-gc-observations.ts b/packages/@overeng/megarepo/src/lib/store-gc-observations.ts
index 81d0a28b23..f3e7ba60e5 100644
--- a/packages/@overeng/megarepo/src/lib/store-gc-observations.ts
+++ b/packages/@overeng/megarepo/src/lib/store-gc-observations.ts
@@ -23,12 +23,14 @@
  * conservatively re-arms all grace windows.
  */
 
-import type { Error as PlatformError } from 'effect'
-import { Effect, Schema, type ParseResult } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import { Effect, Schema } from 'effect'
+import * as SchemaError from 'effect/SchemaError'
+import * as FileSystem from 'effect/FileSystem'
 
 import { EffectPath, type AbsoluteDirPath, type AbsoluteFilePath } from '@overeng/effect-path'
 
+import { encodePrettyJson } from './json.ts'
 import * as Observability from './observability.ts'
 import { writeFileAtomic } from './store-fs-atomic.ts'
 
@@ -87,7 +89,7 @@ export const readObservationLedger = ({
     const path = ledgerPath(storeBasePath)
     return yield* fs.readFileString(path).pipe(
       Effect.flatMap((content) =>
-        Schema.decodeUnknown(Schema.fromJsonString(GcObservationLedger))(content),
+        Schema.decodeUnknownEffect(Schema.fromJsonString(GcObservationLedger))(content),
       ),
       Effect.orElseSucceed(() => ({}) as GcObservationLedger),
     )
@@ -107,7 +109,7 @@ const writeObservationLedger = ({
   ledger: GcObservationLedger
 }): Effect.Effect<
   void,
-  PlatformError.PlatformError | ParseResult.ParseError,
+  PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
@@ -115,7 +117,7 @@ const writeObservationLedger = ({
     const path = ledgerPath(storeBasePath)
     const stateDir = EffectPath.ops.join(storeBasePath, EffectPath.unsafe.relativeDir('.state/'))
     yield* fs.makeDirectory(stateDir, { recursive: true })
-    const content = yield* Schema.encode(Schema.fromJsonString(GcObservationLedger, { space: 2 }))(
+    const content = yield* encodePrettyJson(GcObservationLedger)(
       ledger,
     )
     yield* writeFileAtomic({ path, content: content + '\n' })
@@ -145,7 +147,7 @@ export const recordObservations = ({
   now: number
 }): Effect.Effect<
   GcObservationLedger,
-  PlatformError.PlatformError | ParseResult.ParseError,
+  PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
diff --git a/packages/@overeng/megarepo/src/lib/store-gc-observations.unit.test.ts b/packages/@overeng/megarepo/src/lib/store-gc-observations.unit.test.ts
index b46cfd3602..faffe89357 100644
--- a/packages/@overeng/megarepo/src/lib/store-gc-observations.unit.test.ts
+++ b/packages/@overeng/megarepo/src/lib/store-gc-observations.unit.test.ts
@@ -1,4 +1,4 @@
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { Effect } from 'effect'
 import { describe, expect, it } from 'vitest'
diff --git a/packages/@overeng/megarepo/src/lib/store-hygiene.ts b/packages/@overeng/megarepo/src/lib/store-hygiene.ts
index 8d37b2ff53..6dbaa37bc5 100644
--- a/packages/@overeng/megarepo/src/lib/store-hygiene.ts
+++ b/packages/@overeng/megarepo/src/lib/store-hygiene.ts
@@ -5,9 +5,9 @@
  * Used by pre-flight checks (sync/lock/pin) and `mr store fix`.
  */
 
-import type { Error as PlatformError } from 'effect'
+import * as PlatformError from 'effect/PlatformError'
 import { Effect, Option, Schema } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import type { ChildProcessSpawner as CommandExecutor } from 'effect/unstable/process'
 
 import {
@@ -112,7 +112,7 @@ export const validateStoreMembers = ({
 }): Effect.Effect<
   StoreIssue[],
   PlatformError.PlatformError,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const fs = yield* FileSystem.FileSystem
@@ -279,7 +279,7 @@ export const runPreflightChecks = ({
 }): Effect.Effect<
   void,
   StoreHygieneError | PlatformError.PlatformError,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const issues = yield* validateStoreMembers({
@@ -363,7 +363,7 @@ export const fixStoreIssues = ({
 }): Effect.Effect<
   FixResult[],
   PlatformError.PlatformError,
-  FileSystem.FileSystem | CommandExecutor.CommandExecutor
+  FileSystem.FileSystem | CommandExecutor.ChildProcessSpawner
 > =>
   Effect.gen(function* () {
     const fs = yield* FileSystem.FileSystem
@@ -447,13 +447,13 @@ export const fixStoreIssues = ({
           // Remove existing broken worktree
           yield* fs
             .remove(worktreePath, { recursive: true })
-            .pipe(Effect.catchAll(() => Effect.void))
+            .pipe(Effect.catch(() => Effect.void))
 
           // Recreate the worktree
           yield* Effect.gen(function* () {
             yield* fs
               .makeDirectory(worktreePath, { recursive: true })
-              .pipe(Effect.catchAll(() => Effect.void))
+              .pipe(Effect.catch(() => Effect.void))
 
             const parsed = parseWorktreeRef(worktreePath)
 
@@ -487,7 +487,7 @@ export const fixStoreIssues = ({
               })
             }
           }).pipe(
-            Effect.catchAll((err) => {
+            Effect.catch((err) => {
               results.push({
                 memberName: issue.memberName,
                 issueType: issue.type,
@@ -553,7 +553,7 @@ export const fixStoreIssues = ({
               message: `cloned bare repo from ${cloneUrl}`,
             })
           }).pipe(
-            Effect.catchAll((err) => {
+            Effect.catch((err) => {
               results.push({
                 memberName: issue.memberName,
                 issueType: issue.type,
diff --git a/packages/@overeng/megarepo/src/lib/store-hygiene.unit.test.ts b/packages/@overeng/megarepo/src/lib/store-hygiene.unit.test.ts
index 39992ab190..e8750e74e3 100644
--- a/packages/@overeng/megarepo/src/lib/store-hygiene.unit.test.ts
+++ b/packages/@overeng/megarepo/src/lib/store-hygiene.unit.test.ts
@@ -1,4 +1,4 @@
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { Effect, Option } from 'effect'
 import { describe, expect, it } from 'vitest'
diff --git a/packages/@overeng/megarepo/src/lib/store-liveness.integration.test.ts b/packages/@overeng/megarepo/src/lib/store-liveness.integration.test.ts
index 34d744de58..a3462d32f3 100644
--- a/packages/@overeng/megarepo/src/lib/store-liveness.integration.test.ts
+++ b/packages/@overeng/megarepo/src/lib/store-liveness.integration.test.ts
@@ -1,5 +1,5 @@
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
 import { Effect, Option } from 'effect'
@@ -26,8 +26,9 @@ const normalizePath = (path: string): string => path.replace(/\/+$/, '')
 
 const runGitCommand = (cwd: string, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...args).pipe(Command.workingDirectory(cwd))
-    const result = yield* Command.string(command)
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', args, { cwd })
+    const result = yield* spawner.string(command)
     return result.trim()
   })
 
@@ -333,7 +334,7 @@ describe('store-liveness', () => {
           store,
         }).pipe(Effect.either)
         // Restore perms regardless of assertion outcome so scoped cleanup works.
-        yield* fs.chmod(reposDir, 0o755).pipe(Effect.catchAll(() => Effect.void))
+        yield* fs.chmod(reposDir, 0o755).pipe(Effect.catch(() => Effect.void))
         // Re-break for the reconcile-all assertion below.
         yield* fs.chmod(reposDir, 0o000)
         expect(strictResult._tag).toBe('Left')
@@ -345,7 +346,7 @@ describe('store-liveness', () => {
           reconcileAllWorkspaces: true,
           now: 1_700_000_002_000,
         })
-        yield* fs.chmod(reposDir, 0o755).pipe(Effect.catchAll(() => Effect.void))
+        yield* fs.chmod(reposDir, 0o755).pipe(Effect.catch(() => Effect.void))
 
         expect(reconciled.paths).toContain(normalizePath(mainWorktreePath))
         expect([...reconciled.uncleanReconcilePaths]).toContain(normalizePath(mainWorktreePath))
diff --git a/packages/@overeng/megarepo/src/lib/store-liveness.ts b/packages/@overeng/megarepo/src/lib/store-liveness.ts
index f95bae1231..14735f95a3 100644
--- a/packages/@overeng/megarepo/src/lib/store-liveness.ts
+++ b/packages/@overeng/megarepo/src/lib/store-liveness.ts
@@ -9,9 +9,10 @@
 
 import { createHash } from 'node:crypto'
 
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
-import { Effect, Option, Schema, type ParseResult } from 'effect'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
+import { Effect, Option, Schema } from 'effect'
+import * as SchemaError from 'effect/SchemaError'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
 
@@ -22,6 +23,7 @@ import {
   parseSourceString,
   readMegarepoConfig,
 } from './config.ts'
+import { encodePrettyJson } from './json.ts'
 import { LOCK_FILE_NAME, readLockFile } from './lock.ts'
 import * as Observability from './observability.ts'
 import { writeFileAtomic } from './store-fs-atomic.ts'
@@ -139,7 +141,7 @@ export const collectWorkspaceLivePaths = ({
   strict?: boolean
 }): Effect.Effect<
   Set<string>,
-  ConfigNotFoundError | PlatformError.PlatformError | ParseResult.ParseError,
+  ConfigNotFoundError | PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
@@ -205,7 +207,7 @@ export const collectWorkspaceLivePathsStrict = ({
   store: MegarepoStore
 }): Effect.Effect<
   Set<string>,
-  ConfigNotFoundError | PlatformError.PlatformError | ParseResult.ParseError,
+  ConfigNotFoundError | PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > => collectWorkspaceLivePaths({ workspaceRoot, store, strict: true })
 
@@ -225,7 +227,7 @@ export const refreshWorkspaceRegistry = ({
   now: number
 }): Effect.Effect<
   StoreWorkspaceRecord,
-  ConfigNotFoundError | PlatformError.PlatformError | ParseResult.ParseError,
+  ConfigNotFoundError | PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
@@ -240,7 +242,7 @@ export const refreshWorkspaceRegistry = ({
 
     const registryDir = workspaceRegistryDir(store)
     yield* fs.makeDirectory(registryDir, { recursive: true })
-    const content = yield* Schema.encode(Schema.fromJsonString(StoreWorkspaceRecord, { space: 2 }))(
+    const content = yield* encodePrettyJson(StoreWorkspaceRecord)(
       record,
     )
     // Atomic (write-temp-then-rename): a concurrent reader (e.g. an under-lock
@@ -286,7 +288,7 @@ const readRegistryRecords = ({
   reconcile?: { now: number } | undefined
 }): Effect.Effect<
   RegistryReadResult,
-  ConfigNotFoundError | PlatformError.PlatformError | ParseResult.ParseError,
+  ConfigNotFoundError | PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
@@ -306,7 +308,7 @@ const readRegistryRecords = ({
       const recordPath = EffectPath.ops.join(registryDir, EffectPath.unsafe.relativeFile(entry))
       const parsed = yield* fs.readFileString(recordPath).pipe(
         Effect.flatMap((content) =>
-          Schema.decodeUnknown(Schema.fromJsonString(StoreWorkspaceRecord))(content),
+          Schema.decodeUnknownEffect(Schema.fromJsonString(StoreWorkspaceRecord))(content),
         ),
         Effect.orElseSucceed(() => null),
       )
@@ -321,7 +323,7 @@ const readRegistryRecords = ({
       // present-but-unreadable workspace must never be pruned.
       if (workspaceExists === false) {
         if (pruneStale === true) {
-          yield* fs.remove(recordPath).pipe(Effect.catchAll(() => Effect.void))
+          yield* fs.remove(recordPath).pipe(Effect.catch(() => Effect.void))
         }
         continue
       }
@@ -345,9 +347,7 @@ const readRegistryRecords = ({
           updatedAt: new Date(reconcile.now).toISOString(),
           livePaths: [...reconciled.paths].toSorted(),
         }
-        const content = yield* Schema.encode(
-          Schema.fromJsonString(StoreWorkspaceRecord, { space: 2 }),
-        )(record)
+        const content = yield* encodePrettyJson(StoreWorkspaceRecord)(record)
         // Atomic rewrite so a concurrent reader never sees a torn record and
         // drops a live workspace's veto right before deletion (decision 0010).
         yield* writeFileAtomic({ path: recordPath, content: content + '\n' })
@@ -396,7 +396,7 @@ export const collectStoreLiveSet = ({
   now?: number | undefined
 }): Effect.Effect<
   StoreLiveSet,
-  ConfigNotFoundError | PlatformError.PlatformError | ParseResult.ParseError,
+  ConfigNotFoundError | PlatformError.PlatformError | SchemaError.SchemaError,
   FileSystem.FileSystem
 > =>
   Effect.gen(function* () {
diff --git a/packages/@overeng/megarepo/src/lib/store-lock.ts b/packages/@overeng/megarepo/src/lib/store-lock.ts
index 49f558eac4..83afe4f76c 100644
--- a/packages/@overeng/megarepo/src/lib/store-lock.ts
+++ b/packages/@overeng/megarepo/src/lib/store-lock.ts
@@ -119,7 +119,7 @@ const withoutPushAcquire = (
 export const makeStoreLockLayerFromBacking = (
   backingLayer: Layer.Layer<DistributedSemaphoreBacking>,
 ) =>
-  Layer.scoped(
+  Layer.effect(
     StoreLock,
     Effect.gen(function* () {
       const backingContext = withoutPushAcquire(yield* Layer.build(backingLayer))
@@ -136,7 +136,7 @@ export const makeStoreLockLayerFromBacking = (
  * Lock files stored in {basePath}.locks/ directory.
  */
 export const makeStoreLockLayer = (basePath: AbsoluteDirPath) =>
-  Layer.scoped(
+  Layer.effect(
     StoreLock,
     Effect.gen(function* () {
       const lockDir = `${basePath}.locks`
diff --git a/packages/@overeng/megarepo/src/lib/store-lossless.integration.test.ts b/packages/@overeng/megarepo/src/lib/store-lossless.integration.test.ts
index 4e2b26a581..0d787426e3 100644
--- a/packages/@overeng/megarepo/src/lib/store-lossless.integration.test.ts
+++ b/packages/@overeng/megarepo/src/lib/store-lossless.integration.test.ts
@@ -9,8 +9,8 @@
  * not.
  */
 
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
 import { Effect } from 'effect'
@@ -25,8 +25,9 @@ const GIT_USER = ['-c', 'user.email=test@example.com', '-c', 'user.name=Test Use
 /** Run git in `cwd`, returning trimmed stdout. */
 const git = (cwd: string, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...GIT_USER, ...args).pipe(Command.workingDirectory(cwd))
-    const result = yield* Command.string(command)
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', [...GIT_USER, ...args], { cwd })
+    const result = yield* spawner.string(command)
     return result.trim()
   })
 
@@ -39,11 +40,13 @@ const git = (cwd: string, ...args: ReadonlyArray<string>) =>
  */
 const createStash = (worktreeCwd: string) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...GIT_USER, 'stash').pipe(
-      Command.workingDirectory(worktreeCwd),
-      Command.env({ AGENT_POLICY_BYPASS: '1' }),
-    )
-    yield* Command.string(command)
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', [...GIT_USER, 'stash'], {
+      cwd: worktreeCwd,
+      env: { AGENT_POLICY_BYPASS: '1' },
+      extendEnv: true,
+    })
+    yield* spawner.string(command)
   })
 
 /**
diff --git a/packages/@overeng/megarepo/src/lib/store-pr-state.ts b/packages/@overeng/megarepo/src/lib/store-pr-state.ts
index 9dd8ec0349..1a2dfb0bc8 100644
--- a/packages/@overeng/megarepo/src/lib/store-pr-state.ts
+++ b/packages/@overeng/megarepo/src/lib/store-pr-state.ts
@@ -188,14 +188,14 @@ export const makePrStateResolverLayer = ({
 }: {
   limit?: number
   timeout?: Duration.DurationInput
-} = {}): Layer.Layer<PrStateResolver, never, CommandExecutor.CommandExecutor> =>
+} = {}): Layer.Layer<PrStateResolver, never, CommandExecutor.ChildProcessSpawner> =>
   Layer.effect(
     PrStateResolver,
     Effect.gen(function* () {
       // Capture the executor once at layer build so the service's `resolve`
       // effects discharge their `CommandExecutor` requirement here (the live
       // shelling is an implementation detail, not part of the service R-channel).
-      const executor = yield* CommandExecutor.CommandExecutor
+      const executor = yield* CommandExecutor.ChildProcessSpawner
 
       /** repo `owner/repo` -> decoded PR rows (Option.none ⇒ resolved to no evidence). */
       const repoCache = new Map<string, Option.Option<ReadonlyArray<GhPr>>>()
@@ -208,8 +208,7 @@ export const makePrStateResolverLayer = ({
         repo: string
       }): Effect.Effect<Option.Option<ReadonlyArray<GhPr>>> =>
         Effect.gen(function* () {
-          const command = Command.make(
-            'gh',
+          const command = Command.make('gh', [
             'pr',
             'list',
             '--repo',
@@ -220,15 +219,15 @@ export const makePrStateResolverLayer = ({
             String(limit),
             '--json',
             'number,state,headRefName,mergedAt,closedAt',
-          )
-          const raw = yield* Command.string(command).pipe(
+          ])
+          const raw = yield* executor.string(command).pipe(
             Effect.timeoutFail({
               duration: timeout,
               onTimeout: () => new Error('gh pr list timed out'),
             }),
             // Any spawn/exec/timeout failure ⇒ no evidence (keep).
             Effect.option,
-            Effect.provideService(CommandExecutor.CommandExecutor, executor),
+            Effect.provideService(CommandExecutor.ChildProcessSpawner, executor),
           )
           return Option.flatMap(raw, decodePrListJson)
         })
diff --git a/packages/@overeng/megarepo/src/lib/store.ts b/packages/@overeng/megarepo/src/lib/store.ts
index d501e45e82..bfc5f9e42e 100644
--- a/packages/@overeng/megarepo/src/lib/store.ts
+++ b/packages/@overeng/megarepo/src/lib/store.ts
@@ -20,8 +20,8 @@
  * ```
  */
 
-import type { Error as PlatformError } from 'effect'
-import { FileSystem } from 'effect/FileSystem'
+import * as PlatformError from 'effect/PlatformError'
+import * as FileSystem from 'effect/FileSystem'
 import { Context, Effect, Layer, Option } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath, type RelativeDirPath } from '@overeng/effect-path'
@@ -489,7 +489,7 @@ export const StoreLayer = Layer.effect(
 ).pipe((storeOnly) => {
   /* Derive basePath at provision time for the lock layer.
    * We read the env var again (same as storeOnly) so both use the same path. */
-  const lockLayer = Layer.scoped(
+  const lockLayer = Layer.effect(
     StoreLock,
     Effect.gen(function* () {
       const store = yield* Store
diff --git a/packages/@overeng/megarepo/src/lib/sync/member.ts b/packages/@overeng/megarepo/src/lib/sync/member.ts
index 5c9acdd75e..47e6a19c7e 100644
--- a/packages/@overeng/megarepo/src/lib/sync/member.ts
+++ b/packages/@overeng/megarepo/src/lib/sync/member.ts
@@ -6,7 +6,7 @@
 
 import path from 'node:path'
 
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Option } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
@@ -538,12 +538,12 @@ export const syncMember = <R = never>({
         }
         yield* Observability.annotateSyncMemberAction('skip-dry-run')
       } else if (isFetchMode === true && dryRun === false) {
-        yield* Git.fetchBare({ repoPath: bareRepoPath }).pipe(Effect.catchAll(() => Effect.void))
+        yield* Git.fetchBare({ repoPath: bareRepoPath }).pipe(Effect.catch(() => Effect.void))
         yield* Observability.annotateSyncMemberAction('fetch')
       } else if (isApplyMode === true && targetCommit !== undefined && dryRun === false) {
         const commitExists = yield* Git.refExists({ repoPath: bareRepoPath, ref: targetCommit })
         if (commitExists === false) {
-          yield* Git.fetchBare({ repoPath: bareRepoPath }).pipe(Effect.catchAll(() => Effect.void))
+          yield* Git.fetchBare({ repoPath: bareRepoPath }).pipe(Effect.catch(() => Effect.void))
           yield* Observability.annotateSyncMemberAction('fetch-missing-commit')
         } else {
           yield* Observability.annotateSyncMemberAction('noop')
@@ -693,7 +693,7 @@ export const syncMember = <R = never>({
               repoPath: bareRepoPath,
               ref: `refs/tags/${targetRef}`,
             }).pipe(
-              Effect.catchAll(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
+              Effect.catch(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
             )
           } else if (refInfo.type === 'branch') {
             resolvedRefType = 'branch'
@@ -701,7 +701,7 @@ export const syncMember = <R = never>({
               repoPath: bareRepoPath,
               ref: `refs/remotes/origin/${targetRef}`,
             }).pipe(
-              Effect.catchAll(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
+              Effect.catch(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
             )
           } else {
             const heuristicType = classifyRef(targetRef)
@@ -711,14 +711,14 @@ export const syncMember = <R = never>({
                 repoPath: bareRepoPath,
                 ref: `refs/tags/${targetRef}`,
               }).pipe(
-                Effect.catchAll(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
+                Effect.catch(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
               )
             } else {
               resolvedCommit = yield* Git.resolveRef({
                 repoPath: bareRepoPath,
                 ref: `refs/remotes/origin/${targetRef}`,
               }).pipe(
-                Effect.catchAll(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
+                Effect.catch(() => Git.resolveRef({ repoPath: bareRepoPath, ref: targetRef })),
               )
             }
           }
@@ -844,7 +844,7 @@ export const syncMember = <R = never>({
                 branch: targetRef,
                 createBranch: false,
               }).pipe(
-                Effect.catchAll(() =>
+                Effect.catch(() =>
                   Git.createWorktree({
                     repoPath: bareRepoPath,
                     worktreePath,
@@ -1019,7 +1019,7 @@ export const syncMember = <R = never>({
     } satisfies MemberSyncResult
   }).pipe(
     Effect.tap((result) => Observability.annotateSyncMemberResult(result.status)),
-    Effect.catchAll((error) => {
+    Effect.catch((error) => {
       // Interpret git errors to provide user-friendly messages
       if (error instanceof Git.GitCommandError) {
         const interpreted = Git.interpretGitError(error)
diff --git a/packages/@overeng/megarepo/src/test-utils/setup.ts b/packages/@overeng/megarepo/src/test-utils/setup.ts
index 8e9abafab7..73148878a5 100644
--- a/packages/@overeng/megarepo/src/test-utils/setup.ts
+++ b/packages/@overeng/megarepo/src/test-utils/setup.ts
@@ -6,13 +6,14 @@
 
 import os from 'node:os'
 
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Schema } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
 
 import { MegarepoConfig } from '../lib/config.ts'
+import { encodePrettyJson } from '../lib/json.ts'
 
 // =============================================================================
 // Types
@@ -55,8 +56,9 @@ export interface WorkspaceResult {
 /** Run a git command in a specific directory */
 export const runGitCommand = (cwd: AbsoluteDirPath, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...args).pipe(Command.workingDirectory(cwd))
-    const result = yield* Command.string(command)
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', args, { cwd })
+    const result = yield* spawner.string(command)
     return result.trim()
   })
 
@@ -195,7 +197,7 @@ export const createWorkspace = (fixture?: WorkspaceFixture) =>
     const config: MegarepoConfig = {
       members: fixture?.members ?? {},
     }
-    const configContent = yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+    const configContent = yield* encodePrettyJson(MegarepoConfig)(
       config,
     )
     yield* fs.writeFileString(
@@ -332,7 +334,7 @@ export const readConfig = (workspacePath: AbsoluteDirPath) =>
       EffectPath.unsafe.relativeFile('megarepo.json'),
     )
     const content = yield* fs.readFileString(configPath)
-    return yield* Schema.decodeUnknown(Schema.fromJsonString(MegarepoConfig))(content)
+    return yield* Schema.decodeUnknownEffect(Schema.fromJsonString(MegarepoConfig))(content)
   })
 
 /** Generate a megarepo.json config object */
diff --git a/packages/@overeng/megarepo/src/test-utils/store-setup.integration.test.ts b/packages/@overeng/megarepo/src/test-utils/store-setup.integration.test.ts
index fc6ea376b3..d238f6f90e 100644
--- a/packages/@overeng/megarepo/src/test-utils/store-setup.integration.test.ts
+++ b/packages/@overeng/megarepo/src/test-utils/store-setup.integration.test.ts
@@ -1,5 +1,5 @@
-import { ChildProcess as Command } from 'effect/unstable/process'
-import { FileSystem } from 'effect/FileSystem'
+import { ChildProcess as Command, ChildProcessSpawner } from 'effect/unstable/process'
+import * as FileSystem from 'effect/FileSystem'
 import { NodeServices } from '@effect/platform-node'
 import { describe, it } from '@effect/vitest'
 import { Effect } from 'effect'
@@ -17,8 +17,9 @@ import {
 
 const git = (cwd: AbsoluteDirPath, ...args: ReadonlyArray<string>) =>
   Effect.gen(function* () {
-    const command = Command.make('git', ...args).pipe(Command.workingDirectory(cwd))
-    return (yield* Command.string(command)).trim()
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const command = Command.make('git', args, { cwd })
+    return (yield* spawner.string(command)).trim()
   })
 
 describe('store-setup fixtures', () => {
diff --git a/packages/@overeng/megarepo/src/test-utils/store-setup.ts b/packages/@overeng/megarepo/src/test-utils/store-setup.ts
index 4e3e9db8a8..52823fab1e 100644
--- a/packages/@overeng/megarepo/src/test-utils/store-setup.ts
+++ b/packages/@overeng/megarepo/src/test-utils/store-setup.ts
@@ -4,12 +4,13 @@
  * Provides helpers for creating test stores with bare repos and worktrees.
  */
 
-import { FileSystem } from 'effect/FileSystem'
+import * as FileSystem from 'effect/FileSystem'
 import { Effect, Option, Schema } from 'effect'
 
 import { EffectPath, type AbsoluteDirPath } from '@overeng/effect-path'
 
 import { MegarepoConfig } from '../lib/config.ts'
+import { encodePrettyJson } from '../lib/json.ts'
 import * as Git from '../lib/git.ts'
 import {
   createLockedMember,
@@ -194,7 +195,7 @@ export const createStoreFixture = (repos: ReadonlyArray<StoreRepoFixture>) =>
         yield* Effect.gen(function* () {
           yield* runGitCommand(sourceRepoPath, 'remote', 'add', 'origin', pushTargetPath)
           yield* runGitCommand(sourceRepoPath, 'push', '-u', 'origin', 'main').pipe(
-            Effect.catchAll(() =>
+            Effect.catch(() =>
               // Try master if main fails
               runGitCommand(sourceRepoPath, 'push', '-u', 'origin', 'master'),
             ),
@@ -203,10 +204,10 @@ export const createStoreFixture = (repos: ReadonlyArray<StoreRepoFixture>) =>
           for (const branch of repoFixture.branches ?? []) {
             if (branch === 'main' || branch === 'master') continue
             yield* runGitCommand(sourceRepoPath, 'branch', branch, commitSha).pipe(
-              Effect.catchAll(() => Effect.void),
+              Effect.catch(() => Effect.void),
             )
             yield* runGitCommand(sourceRepoPath, 'push', 'origin', branch).pipe(
-              Effect.catchAll(() => Effect.void),
+              Effect.catch(() => Effect.void),
             )
           }
 
@@ -389,7 +390,7 @@ export const createWorkspaceWithLock = (args: {
     const config: MegarepoConfig = {
       members: args.members,
     }
-    const configContent = yield* Schema.encode(Schema.fromJsonString(MegarepoConfig, { space: 2 }))(
+    const configContent = yield* encodePrettyJson(MegarepoConfig)(
       config,
     )
     yield* fs.writeFileString(
@@ -463,7 +464,7 @@ export const repinWorkspace = ({
     yield* fs.makeDirectory(reposDir, { recursive: true })
     const symlinkPath = EffectPath.ops.join(reposDir, EffectPath.unsafe.relativeFile(memberName))
     // Replace any existing symlink so the new target is the on-disk truth.
-    yield* fs.remove(symlinkPath, { force: true }).pipe(Effect.catchAll(() => Effect.void))
+    yield* fs.remove(symlinkPath, { force: true }).pipe(Effect.catch(() => Effect.void))
     yield* fs.symlink(newTarget.replace(/\/+$/, ''), symlinkPath)
 
     // Optionally rewrite the lock entry for this member (ref/commit repin),
@@ -516,7 +517,7 @@ export const materializeNonDetachedBranchWorktree = ({
     yield* runGitCommand(bareRepoPath, 'worktree', 'remove', '--force', worktreePath)
     yield* fs
       .remove(worktreePath, { recursive: true, force: true })
-      .pipe(Effect.catchAll(() => Effect.void))
+      .pipe(Effect.catch(() => Effect.void))
     // Ensure the branch ref points at this fixture commit, then check it out in
     // a fresh worktree (non-detached).
     yield* runGitCommand(bareRepoPath, 'branch', '-f', branch, commit)