diff --git a/src/commands/ads.test.ts b/src/commands/ads.test.ts
deleted file mode 100644
index 1acf9646c..000000000
--- a/src/commands/ads.test.ts
+++ /dev/null
@@ -1,90 +0,0 @@
-import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
-import type * as React from 'react'
-import adsCmd from './ads.js'
-import { getGlobalConfig, saveGlobalConfig } from '../utils/config.js'
-
-const ORIGINAL_ADS_BASE_URL = process.env.ADS_BASE_URL
-const ORIGINAL_ADS_CONFIG = getGlobalConfig().ads
-
-// Point at an unreachable host so nothing in these tests hits the network.
-// (bun test sets NODE_ENV=test, so saveGlobalConfig writes in-memory.)
-beforeEach(() => {
-  process.env.ADS_BASE_URL = 'http://127.0.0.1:0'
-  saveGlobalConfig(c => ({ ...c, ads: undefined }))
-})
-
-// Restore env + global ads config so neither leaks into other suites in the run.
-afterEach(() => {
-  saveGlobalConfig(c => ({ ...c, ads: ORIGINAL_ADS_CONFIG }))
-  if (ORIGINAL_ADS_BASE_URL === undefined) delete process.env.ADS_BASE_URL
-  else process.env.ADS_BASE_URL = ORIGINAL_ADS_BASE_URL
-})
-
-type RunResult = { text: string | undefined; node: React.ReactNode }
-
-async function run(args: string): Promise<RunResult> {
-  const { call } = await adsCmd.load()
-  let text: string | undefined
-  const onDone = (result?: string): void => {
-    text = result
-  }
-  const node = await call(onDone, {} as never, args)
-  return { text, node }
-}
-
-describe('/ads command', () => {
-  test('status shows off by default', async () => {
-    const { text } = await run('')
-    expect(text).toContain('off')
-  })
-
-  test('"on" returns the masked dialog and does not enable yet', async () => {
-    const { node, text } = await run('on')
-    expect(node).toBeTruthy() // renders AdsCodeDialog
-    expect(text).toBeUndefined() // resolves only after the user submits
-    expect(getGlobalConfig().ads?.enabled).toBeFalsy()
-  })
-
-  test('"on <code>" never enables inline — it also opens the masked dialog', async () => {
-    const { node, text } = await run('on earn_typed_inline')
-    expect(node).toBeTruthy()
-    expect(text).toBeUndefined()
-    // A code typed inline is already exposed → the dialog must warn to rotate it.
-    expect(
-      (node as React.ReactElement<{ warnExposed?: boolean }>).props.warnExposed,
-    ).toBe(true)
-    // The inline code is ignored; nothing is persisted from the command line.
-    expect(getGlobalConfig().ads?.enabled).toBeFalsy()
-  })
-
-  test('"off" disables earning and clears the stored code', async () => {
-    saveGlobalConfig(c => ({ ...c, ads: { enabled: true, earnCode: 'x' } }))
-    const { text } = await run('off')
-    expect(text?.toLowerCase()).toContain('disabled')
-    expect(getGlobalConfig().ads?.enabled).toBe(false)
-    // The earn code is a credential — it must not survive opt-out.
-    expect(getGlobalConfig().ads?.earnCode).toBeUndefined()
-  })
-
-  test('submitting the masked dialog enables earning and persists the code', async () => {
-    const { call } = await adsCmd.load()
-    let text: string | undefined
-    const node = await call((r?: string) => { text = r }, {} as never, 'on')
-    const props = (node as React.ReactElement<{ onSubmit: (code: string) => void }>)
-      .props
-    props.onSubmit('earn_submitted')
-    expect(getGlobalConfig().ads?.enabled).toBe(true)
-    expect(getGlobalConfig().ads?.earnCode).toBe('earn_submitted')
-    expect(text?.toLowerCase()).toContain('enabled')
-  })
-
-  test('cancelling the masked dialog leaves earning off', async () => {
-    const { call } = await adsCmd.load()
-    let text: string | undefined
-    const node = await call((r?: string) => { text = r }, {} as never, 'on')
-    const props = (node as React.ReactElement<{ onCancel: () => void }>).props
-    props.onCancel()
-    expect(getGlobalConfig().ads?.enabled).toBeFalsy()
-    expect(text?.toLowerCase()).toContain('cancel')
-  })
-})
diff --git a/src/commands/ads.test.tsx b/src/commands/ads.test.tsx
new file mode 100644
index 000000000..532a60513
--- /dev/null
+++ b/src/commands/ads.test.tsx
@@ -0,0 +1,141 @@
+import {
+  afterAll,
+  afterEach,
+  beforeAll,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  test,
+} from 'bun:test'
+import type * as React from 'react'
+import type * as ConfigModule from '../utils/config.js'
+
+const ADS_TEST_CONFIG_URL = `../utils/config.js?adsTest=${Date.now()}-${Math.random()}`
+const ORIGINAL_ADS_BASE_URL = process.env.ADS_BASE_URL
+
+// Load the real config module through a unique URL specifier. mock.module() is
+// process-global in bun:test and is NOT reliably undone by afterEach, so a
+// leaked mock.module('../utils/config.js') from another suite can make these
+// assertions read stale state or write into a no-op mock. A query-suffixed
+// specifier is a different module key that mock.module never replaces, so we
+// always get a reference to the real module here.
+let realConfig: typeof ConfigModule
+
+// In-memory config store isolated from the shared test config and from any
+// leaked mocks. ads.tsx imports config.js via the bare specifier, so we install
+// a controlled mock for that specifier while this file runs.
+let testConfig: ConfigModule.GlobalConfig
+
+beforeAll(async () => {
+  realConfig = (await import(ADS_TEST_CONFIG_URL)) as typeof ConfigModule
+})
+
+beforeEach(() => {
+  testConfig = { ...realConfig.DEFAULT_GLOBAL_CONFIG }
+  mock.module('../utils/config.js', () => ({
+    getGlobalConfig: () => testConfig,
+    saveGlobalConfig: (
+      updater: (current: ConfigModule.GlobalConfig) => ConfigModule.GlobalConfig,
+    ) => {
+      const next = updater(testConfig)
+      if (next !== testConfig) {
+        testConfig = next
+      }
+    },
+  }))
+  // Point at an unreachable host so nothing in these tests hits the network.
+  process.env.ADS_BASE_URL = 'http://127.0.0.1:0'
+})
+
+afterEach(() => {
+  mock.restore()
+  if (ORIGINAL_ADS_BASE_URL === undefined) delete process.env.ADS_BASE_URL
+  else process.env.ADS_BASE_URL = ORIGINAL_ADS_BASE_URL
+})
+
+afterAll(() => {
+  // Restore the real config module for subsequent suites.
+  mock.module('../utils/config.js', () => realConfig)
+})
+
+type RunResult = { text: string | undefined; node: React.ReactNode }
+
+async function loadAds() {
+  // Import ads.tsx through a unique URL so it resolves config.js against our
+  // mock rather than a possibly-leaked mock from another suite.
+  const { default: adsCmd } = await import(
+    `./ads.js?adsTest=${Date.now()}-${Math.random()}`
+  )
+  return adsCmd.load()
+}
+
+async function run(args: string): Promise<RunResult> {
+  const { call } = await loadAds()
+  let text: string | undefined
+  const onDone = (result?: string): void => {
+    text = result
+  }
+  const node = await call(onDone, {} as never, args)
+  return { text, node }
+}
+
+describe('/ads command', () => {
+  test('status shows off by default', async () => {
+    const { text } = await run('')
+    expect(text).toContain('off')
+  })
+
+  test('"on" returns the masked dialog and does not enable yet', async () => {
+    const { node, text } = await run('on')
+    expect(node).toBeTruthy() // renders AdsCodeDialog
+    expect(text).toBeUndefined() // resolves only after the user submits
+    expect(testConfig.ads?.enabled).toBeFalsy()
+  })
+
+  test('"on <code>" never enables inline — it also opens the masked dialog', async () => {
+    const { node, text } = await run('on earn_typed_inline')
+    expect(node).toBeTruthy()
+    expect(text).toBeUndefined()
+    // A code typed inline is already exposed → the dialog must warn to rotate it.
+    expect(
+      (node as React.ReactElement<{ warnExposed?: boolean }>).props.warnExposed,
+    ).toBe(true)
+    // The inline code is ignored; nothing is persisted from the command line.
+    expect(testConfig.ads?.enabled).toBeFalsy()
+  })
+
+  test('"off" disables earning and clears the stored code', async () => {
+    testConfig = {
+      ...testConfig,
+      ads: { enabled: true, earnCode: 'x' },
+    }
+    const { text } = await run('off')
+    expect(text?.toLowerCase()).toContain('disabled')
+    expect(testConfig.ads?.enabled).toBe(false)
+    // The earn code is a credential — it must not survive opt-out.
+    expect(testConfig.ads?.earnCode).toBeUndefined()
+  })
+
+  test('submitting the masked dialog enables earning and persists the code', async () => {
+    const { call } = await loadAds()
+    let text: string | undefined
+    const node = await call((r?: string) => { text = r }, {} as never, 'on')
+    const props = (node as React.ReactElement<{ onSubmit: (code: string) => void }>)
+      .props
+    props.onSubmit('earn_submitted')
+    expect(testConfig.ads?.enabled).toBe(true)
+    expect(testConfig.ads?.earnCode).toBe('earn_submitted')
+    expect(text?.toLowerCase()).toContain('enabled')
+  })
+
+  test('cancelling the masked dialog leaves earning off', async () => {
+    const { call } = await loadAds()
+    let text: string | undefined
+    const node = await call((r?: string) => { text = r }, {} as never, 'on')
+    const props = (node as React.ReactElement<{ onCancel: () => void }>).props
+    props.onCancel()
+    expect(testConfig.ads?.enabled).toBeFalsy()
+    expect(text?.toLowerCase()).toContain('cancel')
+  })
+})
diff --git a/src/utils/taskReport.ts b/src/utils/taskReport.ts
index ba31c8f1e..bfde2d115 100644
--- a/src/utils/taskReport.ts
+++ b/src/utils/taskReport.ts
@@ -1477,8 +1477,8 @@ async function runGit(
       maxBuffer: 1_000_000,
     })
     return {
-      stdout: result.stdout,
-      stderr: result.stderr,
+      stdout: typeof result.stdout === 'string' ? result.stdout : '',
+      stderr: typeof result.stderr === 'string' ? result.stderr : '',
       code: result.exitCode ?? 0,
     }
   } catch (error) {