@@ -0,0 +1,6 @@
+---
+"@open-codesign/desktop": patch
+"@open-codesign/i18n": patch
+---
+
+Send a system notification when a design run completes or fails, or when the agent asks a question, while the window is in the background. Clicking it brings the window back and opens that design. New installs start with notifications on. Installs upgraded from an earlier version keep them off until you turn on Settings → Advanced → System notifications; the same switch turns them off. On macOS, notifications stop after the last window is closed, until it is opened again. Preferences move to schema version 10.
@@ -224,6 +224,9 @@ if (!IS_VITEST) {
         app.quit();
         return;
       }
+      // Windows shows toasts only for the AppUserModelID on the installer's
+      // Start Menu shortcut, which electron-builder sets to the appId.
+      if (process.platform === 'win32') app.setAppUserModelId('ai.opencowork.codesign');
       app.on('second-instance', () => {
         if (mainWindow) {
           if (mainWindow.isMinimized()) mainWindow.restore();
 
@@ -1,7 +1,7 @@
 import { mkdir } from 'node:fs/promises';
 import path_module from 'node:path';
 import { CodesignError } from '@open-codesign/shared';
-import { app, ipcMain, shell } from '../electron-runtime';
+import { app, BrowserWindow, ipcMain, shell } from '../electron-runtime';
 import { getLogPath } from '../logger';
 import { isAllowedExternalUrl } from '../open-external';
 
@@ -25,4 +25,11 @@ export function registerShellIpc(): void {
     }
     await shell.openExternal(url);
   });
+
+  ipcMain.handle('codesign:v1:focus-window', (event) => {
+    const win = BrowserWindow.fromWebContents(event.sender);
+    if (win?.isMinimized()) win.restore();
+    win?.show();
+    win?.focus();
+  });
 }
@@ -66,6 +66,7 @@ describe('readPersisted()', () => {
       workspaceMemoryAutoUpdate: true,
       userMemoryAutoUpdate: false,
       proxyUrl: '',
+      systemNotifications: true,
     });
   });
 
@@ -241,7 +242,7 @@ describe('readPersisted()', () => {
       schemaVersion: number;
       diagnosticsLastReadTs: number;
     };
-    expect(written.schemaVersion).toBe(9);
+    expect(written.schemaVersion).toBe(10);
     expect(written.diagnosticsLastReadTs).toBe(result.diagnosticsLastReadTs);
     expect(written.diagnosticsLastReadTs).toBeGreaterThanOrEqual(before);
     expect(written.diagnosticsLastReadTs).toBeLessThanOrEqual(after);
@@ -361,7 +362,7 @@ describe('preferences memory schema fields', () => {
       workspaceMemoryAutoUpdate: boolean;
       userMemoryAutoUpdate: boolean;
     };
-    expect(written.schemaVersion).toBe(9);
+    expect(written.schemaVersion).toBe(10);
     expect(written.memoryEnabled).toBe(false);
     expect(written.workspaceMemoryAutoUpdate).toBe(false);
     expect(written.userMemoryAutoUpdate).toBe(true);
@@ -402,6 +403,66 @@ describe('preferences memory schema fields', () => {
       }),
     ).rejects.toThrow(/proxyUrl must be a string/);
   });
+
+  it('leaves system notifications off for installs upgraded from an earlier schema', async () => {
+    readFileMock.mockResolvedValueOnce(
+      JSON.stringify({ schemaVersion: 9, diagnosticsLastReadTs: 1, proxyUrl: '' }),
+    );
+
+    const prefs = await readPersisted();
+    expect(prefs.systemNotifications).toBe(false);
+  });
+
+  it('keeps an upgraded install opted out when another preference is saved', async () => {
+    readFileMock.mockResolvedValueOnce(
+      JSON.stringify({ schemaVersion: 9, diagnosticsLastReadTs: 1, proxyUrl: '' }),
+    );
+    await (handlers['preferences:v1:update'] as (_e: null, raw: unknown) => Promise<unknown>)(
+      null,
+      { proxyUrl: 'http://127.0.0.1:7890' },
+    );
+
+    const lastCall = writeFileMock.mock.calls.at(-1);
+    if (!lastCall) throw new Error('writeFile was not called');
+    const written = JSON.parse(lastCall[1] as string) as {
+      schemaVersion: number;
+      systemNotifications: boolean;
+    };
+    expect(written.schemaVersion).toBe(10);
+    expect(written.systemNotifications).toBe(false);
+  });
+
+  it('round-trips systemNotifications through preferences:v1:update', async () => {
+    readFileMock.mockResolvedValueOnce(
+      JSON.stringify({ schemaVersion: 10, diagnosticsLastReadTs: 1, systemNotifications: true }),
+    );
+    const updated = await (
+      handlers['preferences:v1:update'] as (_e: null, raw: unknown) => Promise<unknown>
+    )(null, { systemNotifications: false });
+
+    expect((updated as { systemNotifications: boolean }).systemNotifications).toBe(false);
+    const lastCall = writeFileMock.mock.calls.at(-1);
+    if (!lastCall) throw new Error('writeFile was not called');
+    const written = JSON.parse(lastCall[1] as string) as {
+      schemaVersion: number;
+      systemNotifications: boolean;
+    };
+    expect(written.schemaVersion).toBe(10);
+    expect(written.systemNotifications).toBe(false);
+  });
+
+  it('rejects non-boolean systemNotifications updates and persisted values', async () => {
+    await expect(
+      (handlers['preferences:v1:update'] as (_e: null, raw: unknown) => Promise<unknown>)(null, {
+        systemNotifications: 'yes',
+      }),
+    ).rejects.toThrow(/systemNotifications must be a boolean/);
+
+    readFileMock.mockResolvedValueOnce(
+      JSON.stringify({ schemaVersion: 10, diagnosticsLastReadTs: 1, systemNotifications: 1 }),
+    );
+    await expect(readPersisted()).rejects.toThrow(/systemNotifications must be a boolean/);
+  });
 });
 
 describe('applyProxyConfig()', () => {
 
@@ -17,14 +17,18 @@ import { getLogger } from './logger';
 
 const logger = getLogger('preferences-ipc');
 
-const SCHEMA_VERSION = 9;
+const SCHEMA_VERSION = 10;
 // v1 → v2: raise the abandoned 120s timeout default (which aborted real
 // agentic runs mid-loop) to 600s. Values that happen to equal the old
 // default are treated as unmigrated defaults, not user intent.
 const V1_DEFAULT_TIMEOUT_SEC = 120;
 // v2 -> v3: 600s still clips slower long-form multi-turn runs, so the default
 // moves to 1200s.
 const V2_DEFAULT_TIMEOUT_SEC = 600;
+// v9 -> v10: system notifications. Installs upgraded from an earlier schema
+// keep them off until the user turns them on in Settings -> Advanced; new
+// installs start with them on.
+const SYSTEM_NOTIFICATIONS_SCHEMA_VERSION = 10;
 
 function prefsFile(): string {
   return join(configDir(), 'preferences.json');
@@ -47,6 +51,8 @@ export interface Preferences {
   /** HTTP/HTTPS proxy URL applied to Chromium and Node outbound traffic.
    *  Empty string disables the proxy. */
   proxyUrl: string;
+  /** Notify through the OS when a design run ends or asks a question while the window is in the background. */
+  systemNotifications: boolean;
 }
 
 interface PreferencesFile extends Preferences {
@@ -67,6 +73,7 @@ const DEFAULTS: Preferences = {
   workspaceMemoryAutoUpdate: true,
   userMemoryAutoUpdate: false,
   proxyUrl: '',
+  systemNotifications: true,
 };
 
 const PREFERENCE_UPDATE_FIELDS = [
@@ -79,6 +86,7 @@ const PREFERENCE_UPDATE_FIELDS = [
   'workspaceMemoryAutoUpdate',
   'userMemoryAutoUpdate',
   'proxyUrl',
+  'systemNotifications',
 ] as const;
 
 function assertKnownPreferenceFields(r: Record<string, unknown>): void {
@@ -137,7 +145,8 @@ function readPersistedBoolean(
     | 'checkForUpdatesOnStartup'
     | 'memoryEnabled'
     | 'workspaceMemoryAutoUpdate'
-    | 'userMemoryAutoUpdate',
+    | 'userMemoryAutoUpdate'
+    | 'systemNotifications',
   defaultValue: boolean,
 ): boolean {
   const value = r[key];
@@ -224,6 +233,11 @@ function parsePersistedFile(rawJson: unknown): Preferences {
       DEFAULTS.userMemoryAutoUpdate,
     ),
     proxyUrl: readPersistedString(parsed, 'proxyUrl', DEFAULTS.proxyUrl),
+    systemNotifications: readPersistedBoolean(
+      parsed,
+      'systemNotifications',
+      persistedSchema < SYSTEM_NOTIFICATIONS_SCHEMA_VERSION ? false : DEFAULTS.systemNotifications,
+    ),
   };
 }
 
@@ -332,6 +346,15 @@ function readMemoryAutoUpdate(
   return value;
 }
 
+function readSystemNotifications(r: Record<string, unknown>): boolean | undefined {
+  const value = r['systemNotifications'];
+  if (value === undefined) return undefined;
+  if (typeof value !== 'boolean') {
+    throw new CodesignError('systemNotifications must be a boolean', ERROR_CODES.IPC_BAD_INPUT);
+  }
+  return value;
+}
+
 function readDismissedVersion(r: Record<string, unknown>): string | undefined {
   const value = r['dismissedUpdateVersion'];
   if (value === undefined) return undefined;
@@ -389,6 +412,8 @@ function parsePreferences(raw: unknown): Partial<Preferences> {
   if (userMemoryAutoUpdate !== undefined) out.userMemoryAutoUpdate = userMemoryAutoUpdate;
   const proxyUrl = readProxyUrl(r);
   if (proxyUrl !== undefined) out.proxyUrl = proxyUrl;
+  const systemNotifications = readSystemNotifications(r);
+  if (systemNotifications !== undefined) out.systemNotifications = systemNotifications;
   return out;
 }
 
 
@@ -272,6 +272,7 @@ export interface Preferences {
   workspaceMemoryAutoUpdate: boolean;
   userMemoryAutoUpdate: boolean;
   proxyUrl: string;
+  systemNotifications: boolean;
 }
 
 export interface MemoryFileRead {
@@ -1019,6 +1020,7 @@ const api = {
   },
   openExternal: (url: string) =>
     ipcRenderer.invoke('codesign:v1:open-external', url) as Promise<void>,
+  focusWindow: () => ipcRenderer.invoke('codesign:v1:focus-window') as Promise<void>,
   ask: {
     history: (filter?: { runId?: string; designId?: string }) =>
       ipcRenderer.invoke('ask:history', filter) as Promise<AskHistoryEntry[]>,
 
@@ -16,6 +16,7 @@ import { UpdateBanner } from './components/UpdateBanner';
 import { useAgentStream } from './hooks/useAgentStream';
 import { useKeyboard } from './hooks/useKeyboard';
 import { useUpdateWiring } from './hooks/useUpdateWiring';
+import { notifyDesignInBackground } from './lib/system-notifications';
 
 // Settings opens in a separate view (Hub ↔ Workspace ↔ Settings). Keep it
 // out of the first-paint chunk — its ~2700-line tree + dynamic provider
@@ -71,6 +72,16 @@ export function App() {
   const [updateStore] = useState(() => createUpdateStore({ dismissedVersion: '' }));
   useUpdateWiring(updateStore);
   useAgentStream();
+  useEffect(() => {
+    const off = window.codesign?.ask?.onRequest?.((request) => {
+      notifyDesignInBackground(useCodesignStore.getState(), request.designId, 'ask').catch(
+        (error: unknown) => console.warn('[open-codesign] system notification failed:', error),
+      );
+    });
+    return () => {
+      off?.();
+    };
+  }, []);
 
   useEffect(() => {
     if (!window.codesign) {
 
@@ -71,6 +71,7 @@ export function AdvancedTab() {
     workspaceMemoryAutoUpdate: true,
     userMemoryAutoUpdate: false,
     proxyUrl: '',
+    systemNotifications: true,
   });
 
   useEffect(() => {
@@ -142,6 +143,19 @@ export function AdvancedTab() {
         />
       </Row>
 
+      <Row
+        label={t('settings.advanced.systemNotifications')}
+        hint={t('settings.advanced.systemNotificationsHint')}
+      >
+        <input
+          type="checkbox"
+          checked={prefs.systemNotifications}
+          aria-label={t('settings.advanced.systemNotifications')}
+          onChange={(e) => void updatePref({ systemNotifications: e.target.checked })}
+          className="h-4 w-4 accent-[var(--color-accent)]"
+        />
+      </Row>
+
       <Row label={t('settings.advanced.timeout')} hint={t('settings.advanced.timeoutHint')}>
         <NativeSelect
           value={String(prefs.generationTimeoutSec)}
 
@@ -15,6 +15,7 @@ const DEFAULT_PREFS: Preferences = {
   workspaceMemoryAutoUpdate: true,
   userMemoryAutoUpdate: false,
   proxyUrl: '',
+  systemNotifications: true,
 };
 
 export function MemoryTab() {
 
@@ -43,6 +43,7 @@ const design = {
   workspacePath: '/tmp/codesign-completion-test',
 };
 let listener: ((event: AgentStreamEvent) => void) | undefined;
+let windowFocused = true;
 const append = vi.fn(async (input: { designId: string; kind: string; payload: unknown }) => ({
   ...input,
   id: 'row',
@@ -89,12 +90,19 @@ beforeEach(() => {
     persistAgentRunSnapshot: vi.fn(async () => {}),
     tryAutoPolish: vi.fn(),
   });
+  windowFocused = true;
+  vi.stubGlobal('document', {
+    hasFocus: () => windowFocused,
+    addEventListener: vi.fn(),
+    removeEventListener: vi.fn(),
+  });
   vi.stubGlobal('window', {
     addEventListener: vi.fn(),
     removeEventListener: vi.fn(),
     setTimeout,
     codesign: {
       generate,
+      preferences: { get: vi.fn(async () => ({ systemNotifications: true })) },
       generationStatus: vi.fn(async () => ({ schemaVersion: 1, running: [] })),
       snapshots: {
         list: vi.fn(async () => []),
@@ -127,6 +135,31 @@ afterEach(() => {
 });
 
 describe('agent stream / IPC completion ordering', () => {
+  it('notifies through the OS only for live runs that complete or fail in the background', async () => {
+    const shown: Array<{ title: string; body: string }> = [];
+    vi.stubGlobal(
+      'Notification',
+      class {
+        onclick: (() => void) | null = null;
+        constructor(title: string, options: { body: string }) {
+          shown.push({ title, body: options.body });
+        }
+      },
+    );
+    windowFocused = false;
+
+    emit('run_settled', 'completed-run', { outcome: 'completed' });
+    emit('run_settled', 'failed-run', { outcome: 'failed' });
+    emit('run_settled', 'cancelled-run', { outcome: 'cancelled' });
+    emit('run_settled', 'interrupted-run', { outcome: 'interrupted' });
+    await vi.advanceTimersByTimeAsync(0);
+
+    expect(shown).toEqual([
+      { title: 'Aurora', body: 'Design ready' },
+      { title: 'Aurora', body: 'Generation failed' },
+    ]);
+  });
+
   it('keeps exactly one canonical active message through delivery, turn end and completion', async () => {
     const get = useCodesignStore.getState;
     const rows: ChatMessageRow[] = [];
@@ -500,6 +533,35 @@ describe('durable run refresh recovery', () => {
     expect(append).not.toHaveBeenCalled();
   });
 
+  it('does not notify for run outcomes recovered after a refresh', async () => {
+    const shown: string[] = [];
+    vi.stubGlobal(
+      'Notification',
+      class {
+        onclick: (() => void) | null = null;
+        constructor(title: string) {
+          shown.push(title);
+        }
+      },
+    );
+    windowFocused = false;
+
+    await remount([
+      durable('turn_start', 1),
+      durable('run_settled', 2, { outcome: 'completed' }),
+      { ...durable('turn_start', 1), runId: 'durable-2', generationId: 'durable-2' },
+      {
+        ...durable('run_settled', 2, { outcome: 'failed', message: 'Old failure' }),
+        runId: 'durable-2',
+        generationId: 'durable-2',
+      },
+    ]);
+    await vi.advanceTimersByTimeAsync(0);
+
+    expect(useCodesignStore.getState().isGenerating).toBe(false);
+    expect(shown).toEqual([]);
+  });
+
   it('replays persisted chat and terminal outcomes without duplicate writes or automatic generation', async () => {
     useCodesignStore.setState({ previewSource: 'Edited after generation' });
     await remount([