diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 4888dd6f3b3..1b17bcec075 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -273,6 +273,9 @@ jobs:
       - name: Smoke packaged CLI
         run: node config/scripts/smoke-packaged-cli.mjs --app-dir=dist/linux-unpacked
 
+      - name: Smoke packaged hang watchdog worker
+        run: xvfb-run --auto-servernum node config/scripts/smoke-packaged-hang-watchdog-worker.mjs --app-dir=dist/linux-unpacked
+
   # Why: regression specs under tests/e2e/** used to merge green without ever
   # running — e2e.yml only fired on schedule/release (#10518). Path-filter so
   # ordinary PRs stay light; any E2E suite change still gets a full shard run.
diff --git a/config/scripts/packaged-hang-watchdog-worker-contract.test.mjs b/config/scripts/packaged-hang-watchdog-worker-contract.test.mjs
new file mode 100644
index 00000000000..b084f986eb3
--- /dev/null
+++ b/config/scripts/packaged-hang-watchdog-worker-contract.test.mjs
@@ -0,0 +1,23 @@
+import { readFileSync } from 'node:fs'
+import { parse } from 'yaml'
+import { describe, expect, it } from 'vitest'
+
+describe('packaged hang watchdog worker contract', () => {
+  it('boots the worker from app.asar in PR checks', () => {
+    const workflow = parse(readFileSync('.github/workflows/pr.yml', 'utf8'))
+    const smokeSource = readFileSync(
+      'config/scripts/smoke-packaged-hang-watchdog-worker.mjs',
+      'utf8'
+    )
+    const smokeStep = workflow.jobs.package.steps.find(
+      (step) => step.name === 'Smoke packaged hang watchdog worker'
+    )
+
+    expect(smokeStep.run).toBe(
+      'xvfb-run --auto-servernum node config/scripts/smoke-packaged-hang-watchdog-worker.mjs --app-dir=dist/linux-unpacked'
+    )
+    expect(smokeSource).toContain(
+      "process.platform === 'linux' ? ['--no-sandbox', launcherDir] : [launcherDir]"
+    )
+  })
+})
diff --git a/config/scripts/smoke-packaged-hang-watchdog-worker.mjs b/config/scripts/smoke-packaged-hang-watchdog-worker.mjs
new file mode 100644
index 00000000000..e4b7af33ab9
--- /dev/null
+++ b/config/scripts/smoke-packaged-hang-watchdog-worker.mjs
@@ -0,0 +1,165 @@
+import { spawnSync } from 'node:child_process'
+import { existsSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs'
+import { createRequire } from 'node:module'
+import { tmpdir } from 'node:os'
+import { join, resolve } from 'node:path'
+import { pathToFileURL } from 'node:url'
+import { Worker } from 'node:worker_threads'
+
+const INTERNAL_ENV = 'ORCA_PACKAGED_WATCHDOG_SMOKE_INTERNAL'
+const ASAR_ENV = 'ORCA_PACKAGED_WATCHDOG_SMOKE_ASAR'
+const TIMEOUT_MS = 100
+const CHECK_INTERVAL_MS = 20
+const POLL_TIMEOUT_MS = 5_000
+
+function sleep(ms) {
+  return new Promise((resolveSleep) => setTimeout(resolveSleep, ms))
+}
+
+function readAppDirArg(argv) {
+  const explicit = argv.find((arg) => arg.startsWith('--app-dir='))
+  if (explicit) {
+    return explicit.slice('--app-dir='.length)
+  }
+  if (process.platform === 'darwin') {
+    return 'dist/mac-arm64/Orca.app'
+  }
+  if (process.platform === 'win32') {
+    return 'dist/win-unpacked'
+  }
+  return 'dist/linux-unpacked'
+}
+
+function getResourcesDir(appDir) {
+  return process.platform === 'darwin' || appDir.endsWith('.app')
+    ? join(appDir, 'Contents', 'Resources')
+    : join(appDir, 'resources')
+}
+
+function readMarker(markerPath) {
+  try {
+    return JSON.parse(readFileSync(markerPath, 'utf8'))
+  } catch {
+    return null
+  }
+}
+
+async function waitForMarker(markerPath, predicate, workerError) {
+  const deadline = Date.now() + POLL_TIMEOUT_MS
+  while (Date.now() < deadline) {
+    if (workerError.current) {
+      throw workerError.current
+    }
+    const marker = readMarker(markerPath)
+    if (predicate(marker)) {
+      return marker
+    }
+    await sleep(CHECK_INTERVAL_MS)
+  }
+  throw new Error(`Timed out waiting for packaged watchdog marker at ${markerPath}`)
+}
+
+async function waitForExit(worker, workerError) {
+  const exitCode = await Promise.race([
+    new Promise((resolveExit) => worker.once('exit', resolveExit)),
+    sleep(POLL_TIMEOUT_MS).then(() => {
+      throw new Error('Timed out waiting for packaged watchdog worker to exit')
+    })
+  ])
+  if (workerError.current) {
+    throw workerError.current
+  }
+  if (exitCode !== 0) {
+    throw new Error(`Packaged watchdog worker exited with code ${exitCode}`)
+  }
+}
+
+async function runInternal() {
+  const appAsar = process.env[ASAR_ENV]
+  if (!appAsar) {
+    throw new Error(`Missing ${ASAR_ENV}`)
+  }
+  const { app } = await import('electron')
+  const tempRoot = mkdtempSync(join(tmpdir(), 'orca-packaged-watchdog-smoke-'))
+  const markerPath = join(tempRoot, 'main-thread-hang.json')
+  const entryPath = join(appAsar, 'out', 'main', 'main-thread-hang-watchdog-entry.js')
+  let worker
+  try {
+    await app.whenReady()
+    if (!existsSync(entryPath)) {
+      throw new Error(`Packaged watchdog entry is missing from app.asar: ${entryPath}`)
+    }
+    const workerError = { current: null }
+    worker = new Worker(entryPath, {
+      workerData: {
+        parentPid: process.pid,
+        markerPath,
+        timeoutMs: TIMEOUT_MS,
+        checkIntervalMs: CHECK_INTERVAL_MS
+      }
+    })
+    worker.once('error', (error) => {
+      workerError.current = error
+    })
+    await waitForMarker(markerPath, (marker) => marker?.selfRecovered === false, workerError)
+    worker.postMessage({ type: 'heartbeat' })
+    await waitForMarker(markerPath, (marker) => marker?.selfRecovered === true, workerError)
+    worker.postMessage({ type: 'shutdown' })
+    await waitForExit(worker, workerError)
+    worker = undefined
+    console.log('[packaged-watchdog-smoke] app.asar worker detected and recovered a stall')
+  } finally {
+    await worker?.terminate()
+    app.quit()
+    rmSync(tempRoot, { recursive: true, force: true })
+  }
+}
+
+function runSmoke() {
+  const appDir = resolve(readAppDirArg(process.argv.slice(2)))
+  const appAsar = join(getResourcesDir(appDir), 'app.asar')
+  if (!existsSync(appAsar)) {
+    throw new Error(`Packaged app archive is missing: ${appAsar}`)
+  }
+  const require = createRequire(import.meta.url)
+  const executable = require('electron')
+  const launcherDir = mkdtempSync(join(tmpdir(), 'orca-packaged-watchdog-launcher-'))
+  const launcherPath = join(launcherDir, 'main.cjs')
+  writeFileSync(
+    join(launcherDir, 'package.json'),
+    JSON.stringify({ name: 'orca-packaged-watchdog-smoke', main: 'main.cjs' })
+  )
+  writeFileSync(
+    launcherPath,
+    `import(${JSON.stringify(pathToFileURL(import.meta.filename).href)}).catch((error) => {
+  console.error(error)
+  process.exitCode = 1
+})\n`
+  )
+  const env = { ...process.env, [INTERNAL_ENV]: '1', [ASAR_ENV]: appAsar, NODE_PATH: '' }
+  delete env.ELECTRON_RUN_AS_NODE
+  try {
+    const electronArgs =
+      process.platform === 'linux' ? ['--no-sandbox', launcherDir] : [launcherDir]
+    const result = spawnSync(executable, electronArgs, {
+      env,
+      encoding: 'utf8',
+      timeout: 15_000
+    })
+    if (result.status !== 0) {
+      throw new Error(
+        `Packaged watchdog smoke failed (${result.error?.message ?? result.signal ?? result.status}):\n` +
+          `${result.stderr || result.stdout}`
+      )
+    }
+    process.stdout.write(result.stdout)
+  } finally {
+    rmSync(launcherDir, { recursive: true, force: true })
+  }
+}
+
+if (process.env[INTERNAL_ENV] === '1') {
+  await runInternal()
+} else {
+  runSmoke()
+}
diff --git a/src/main/hang-watchdog/main-thread-hang-watchdog-entry.test.ts b/src/main/hang-watchdog/main-thread-hang-watchdog-entry.test.ts
index 5f4d75b4ad2..a1ececdadb4 100644
--- a/src/main/hang-watchdog/main-thread-hang-watchdog-entry.test.ts
+++ b/src/main/hang-watchdog/main-thread-hang-watchdog-entry.test.ts
@@ -12,7 +12,11 @@ vi.mock('node:child_process', () => ({
   spawn: spawnMock
 }))
 
-import { recordHangObservation } from './main-thread-hang-watchdog-entry'
+import {
+  isHangWatchdogWorkerData,
+  recordHangObservation,
+  runWatchdog
+} from './main-thread-hang-watchdog-entry'
 
 describe('recordHangObservation', () => {
   let dir: string
@@ -102,3 +106,75 @@ describe('recordHangObservation', () => {
     ).not.toThrow()
   })
 })
+
+describe('watchdog worker entry', () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+    vi.setSystemTime(0)
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  it('accepts only complete positive worker data', () => {
+    expect(
+      isHangWatchdogWorkerData({
+        parentPid: 42,
+        markerPath: '/tmp/marker',
+        timeoutMs: 100,
+        checkIntervalMs: 25
+      })
+    ).toBe(true)
+    for (const value of [
+      null,
+      {},
+      { parentPid: 0, markerPath: '/tmp/marker', timeoutMs: 100, checkIntervalMs: 25 },
+      { parentPid: 42, markerPath: 7, timeoutMs: 100, checkIntervalMs: 25 },
+      { parentPid: 42, markerPath: '/tmp/marker', timeoutMs: 0, checkIntervalMs: 25 },
+      { parentPid: 42, markerPath: '/tmp/marker', timeoutMs: 100, checkIntervalMs: Infinity }
+    ]) {
+      expect(isHangWatchdogWorkerData(value)).toBe(false)
+    }
+  })
+
+  it('routes heartbeats and shuts down its timer and port', () => {
+    const markerPath = join(tmpdir(), `hang-watchdog-entry-${process.pid}.json`)
+    let onMessage: ((message: { type: 'heartbeat' | 'shutdown' }) => void) | undefined
+    const port = {
+      on: vi.fn(
+        (_event: 'message', listener: (message: { type: 'heartbeat' | 'shutdown' }) => void) => {
+          onMessage = listener
+        }
+      ),
+      close: vi.fn()
+    }
+    try {
+      runWatchdog(
+        {
+          parentPid: process.pid,
+          markerPath,
+          timeoutMs: 100,
+          checkIntervalMs: 25
+        },
+        port
+      )
+      vi.advanceTimersByTime(75)
+      onMessage?.({ type: 'heartbeat' })
+      vi.advanceTimersByTime(75)
+      expect(consumeHangDetectionMarker(markerPath)).toBeNull()
+      vi.advanceTimersByTime(50)
+      expect(consumeHangDetectionMarker(markerPath)).toMatchObject({ selfRecovered: false })
+
+      onMessage?.({ type: 'heartbeat' })
+      expect(consumeHangDetectionMarker(markerPath)).toMatchObject({ selfRecovered: true })
+      onMessage?.({ type: 'shutdown' })
+      expect(port.close).toHaveBeenCalledOnce()
+      vi.advanceTimersByTime(1_000)
+      expect(port.close).toHaveBeenCalledOnce()
+      expect(consumeHangDetectionMarker(markerPath)).toBeNull()
+    } finally {
+      rmSync(markerPath, { force: true })
+    }
+  })
+})
diff --git a/src/main/hang-watchdog/main-thread-hang-watchdog-entry.ts b/src/main/hang-watchdog/main-thread-hang-watchdog-entry.ts
index 1b100b73566..2c60b17e9ff 100644
--- a/src/main/hang-watchdog/main-thread-hang-watchdog-entry.ts
+++ b/src/main/hang-watchdog/main-thread-hang-watchdog-entry.ts
@@ -6,6 +6,11 @@ import type {
   MainToHangWatchdogWorkerMessage
 } from './hang-watchdog-worker-protocol'
 
+type HangWatchdogPort = {
+  on: (event: 'message', listener: (message: MainToHangWatchdogWorkerMessage) => void) => unknown
+  close: () => void
+}
+
 // Observation only: a false positive must never kill a live main thread mid-write.
 export function recordHangObservation(options: {
   parentPid: number
@@ -28,8 +33,10 @@ export function recordHangObservation(options: {
   }
 }
 
-function runWatchdog(config: HangWatchdogWorkerData): void {
-  const port = parentPort
+export function runWatchdog(
+  config: HangWatchdogWorkerData,
+  port: HangWatchdogPort | null = parentPort
+): void {
   if (!port) {
     return
   }
@@ -71,7 +78,7 @@ function runWatchdog(config: HangWatchdogWorkerData): void {
   })
 }
 
-function isHangWatchdogWorkerData(value: unknown): value is HangWatchdogWorkerData {
+export function isHangWatchdogWorkerData(value: unknown): value is HangWatchdogWorkerData {
   const data = value as Partial<HangWatchdogWorkerData> | null
   return (
     !!data &&