diff --git a/frontend/src/lib/notification/NotificationBell.svelte b/frontend/src/lib/notification/NotificationBell.svelte
index 3a04bb35..38a2513f 100644
--- a/frontend/src/lib/notification/NotificationBell.svelte
+++ b/frontend/src/lib/notification/NotificationBell.svelte
@@ -2,13 +2,13 @@
 import { onMount, onDestroy } from 'svelte';
 import { m } from '$lib/paraglide/messages.js';
 import { clickOutside } from '$lib/shared/actions/clickOutside';
-import { notificationStore } from '$lib/notification/notifications.svelte';
+import { getNotificationStore } from '$lib/notification/notifications.svelte';
 import NotificationDropdown from './NotificationDropdown.svelte';
 
 let open = $state(false);
 let bellButtonEl: HTMLButtonElement | null = null;
 
-const stream = notificationStore;
+const stream = getNotificationStore();
 
 async function toggleDropdown() {
 	open = !open;
diff --git a/frontend/src/lib/notification/NotificationBell.svelte.spec.ts b/frontend/src/lib/notification/NotificationBell.svelte.spec.ts
index bf5f5f62..256ee342 100644
--- a/frontend/src/lib/notification/NotificationBell.svelte.spec.ts
+++ b/frontend/src/lib/notification/NotificationBell.svelte.spec.ts
@@ -1,36 +1,43 @@
-import { afterEach, describe, it, expect, vi } from 'vitest';
+import { afterEach, beforeEach, describe, it, expect, vi } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
+import { m } from '$lib/paraglide/messages.js';
 import type { NotificationItem } from '$lib/notification/notifications';
-import NotificationBell from './NotificationBell.svelte';
 import * as formsMock from '$mocks/$app/forms';
+import NotificationFixture from './notification.test-fixture.svelte';
 
 vi.mock('$app/navigation', () => ({ goto: vi.fn(), beforeNavigate: vi.fn() }));
 vi.mock('$app/forms', () => ({ ...formsMock }));
 
-const mockNotificationList = vi.hoisted((): { value: NotificationItem[] } => ({ value: [] }));
+// NotificationBell.onMount calls store.init(), which opens an EventSource and
+// fetches the unread count. Stub both so no real network or 401 → /login
+// navigation fires; the real store + provideNotificationStore() run otherwise.
+class NoopEventSource {
+	static CLOSED = 2;
+	readyState = 0;
+	onopen: (() => void) | null = null;
+	onerror: (() => void) | null = null;
+	addEventListener() {}
+	close() {}
+}
 
-vi.mock('$lib/notification/notifications.svelte', () => ({
-	notificationStore: {
-		get notifications() {
-			return mockNotificationList.value;
-		},
-		get unreadCount() {
-			return mockNotificationList.value.length;
-		},
-		optimisticMarkRead: vi.fn(),
-		optimisticMarkAllRead: vi.fn(),
-		fetchNotifications: vi.fn().mockResolvedValue(undefined),
-		init: vi.fn(),
-		destroy: vi.fn()
-	}
-}));
+beforeEach(() => {
+	vi.stubGlobal('EventSource', NoopEventSource);
+	vi.stubGlobal(
+		'fetch',
+		vi
+			.fn()
+			.mockResolvedValue(new Response(JSON.stringify({ count: 0, content: [] }), { status: 200 }))
+	);
+});
 
 afterEach(() => {
 	cleanup();
 	vi.clearAllMocks();
-	mockNotificationList.value = [];
+	vi.unstubAllGlobals();
 });
 
+const tick = () => new Promise((r) => setTimeout(r, 0));
+
 const makeNotification = (overrides: Partial<NotificationItem> = {}): NotificationItem => ({
 	id: 'n1',
 	type: 'REPLY',
@@ -44,30 +51,85 @@ const makeNotification = (overrides: Partial<NotificationItem> = {}): Notificati
 	...overrides
 });
 
-describe('NotificationBell — cursor and tooltip', () => {
+type Api = { setNotifications: (items: NotificationItem[]) => void };
+
+function renderBell(): Api {
+	let api: Api = { setNotifications: () => {} };
+	render(NotificationFixture, { onReady: (a: Api) => (api = a) });
+	return api;
+}
+
+function bellButton(): HTMLButtonElement {
+	return document.querySelector<HTMLButtonElement>('button[aria-haspopup="true"]')!;
+}
+
+function unreadBadge(): HTMLElement {
+	return bellButton().querySelector<HTMLElement>('[aria-live="polite"]')!;
+}
+
+describe('NotificationBell — rendering', () => {
 	it('bell button has cursor-pointer class', async () => {
-		render(NotificationBell);
-		const btn = document.querySelector<HTMLButtonElement>('button[aria-haspopup="true"]')!;
-		expect(btn.classList.contains('cursor-pointer')).toBe(true);
-	});
-
-	it('bell button title equals aria-label when unreadCount is 0', async () => {
-		mockNotificationList.value = [];
-		render(NotificationBell);
-		const btn = document.querySelector<HTMLButtonElement>('button[aria-haspopup="true"]')!;
-		expect(btn.getAttribute('title')).toBe('Benachrichtigungen');
-		expect(btn.getAttribute('aria-label')).toBe(btn.getAttribute('title'));
-	});
-
-	it('bell button title equals aria-label when unreadCount is 3', async () => {
-		mockNotificationList.value = [
-			makeNotification({ id: 'n1' }),
-			makeNotification({ id: 'n2' }),
-			makeNotification({ id: 'n3' })
-		];
-		render(NotificationBell);
-		const btn = document.querySelector<HTMLButtonElement>('button[aria-haspopup="true"]')!;
-		expect(btn.getAttribute('title')).toBe('3 ungelesene Benachrichtigungen');
-		expect(btn.getAttribute('aria-label')).toBe(btn.getAttribute('title'));
+		renderBell();
+		await tick();
+		expect(bellButton().classList.contains('cursor-pointer')).toBe(true);
+	});
+});
+
+// AC#5: the bell's announced unread count must hold across the four a11y states.
+// The count is announced via the aria-live badge text and the button title /
+// aria-label; both must stay consistent as the store's notifications change.
+describe('NotificationBell — announced unread count across a11y states', () => {
+	it('empty: announces no unread count and hides the live badge', async () => {
+		const { setNotifications } = renderBell();
+		await tick();
+		setNotifications([]);
+		await tick();
+
+		const btn = bellButton();
+		expect(btn.getAttribute('title')).toBe(m.notification_bell_label());
+		expect(btn.getAttribute('aria-label')).toBe(btn.getAttribute('title'));
+		expect(unreadBadge().classList.contains('hidden')).toBe(true);
+	});
+
+	it('single: announces one unread notification', async () => {
+		const { setNotifications } = renderBell();
+		await tick();
+		setNotifications([makeNotification({ id: 'n1', read: false })]);
+		await tick();
+
+		const btn = bellButton();
+		expect(btn.getAttribute('title')).toBe(m.notification_bell_unread_label({ count: 1 }));
+		expect(btn.getAttribute('aria-label')).toBe(btn.getAttribute('title'));
+		expect(unreadBadge().classList.contains('hidden')).toBe(false);
+		expect(unreadBadge().textContent?.trim()).toBe('1');
+	});
+
+	it('many: announces the exact unread count', async () => {
+		const { setNotifications } = renderBell();
+		await tick();
+		setNotifications([
+			makeNotification({ id: 'n1', read: false }),
+			makeNotification({ id: 'n2', read: false }),
+			makeNotification({ id: 'n3', read: false })
+		]);
+		await tick();
+
+		const btn = bellButton();
+		expect(btn.getAttribute('title')).toBe(m.notification_bell_unread_label({ count: 3 }));
+		expect(btn.getAttribute('aria-label')).toBe(btn.getAttribute('title'));
+		expect(unreadBadge().textContent?.trim()).toBe('3');
+	});
+
+	it('error: degrades to a zero announced count when the unread-count load fails', async () => {
+		vi.stubGlobal('fetch', vi.fn().mockRejectedValue(new Error('network down')));
+		renderBell();
+		await tick();
+
+		// A failed load leaves the count at 0; the bell still announces a valid,
+		// non-urgent state rather than a broken count.
+		const btn = bellButton();
+		expect(btn.getAttribute('title')).toBe(m.notification_bell_label());
+		expect(btn.getAttribute('aria-label')).toBe(btn.getAttribute('title'));
+		expect(unreadBadge().classList.contains('hidden')).toBe(true);
 	});
 });
diff --git a/frontend/src/lib/notification/notification.test-fixture.svelte b/frontend/src/lib/notification/notification.test-fixture.svelte
new file mode 100644
index 00000000..9ebfc484
--- /dev/null
+++ b/frontend/src/lib/notification/notification.test-fixture.svelte
@@ -0,0 +1,13 @@
+<script lang="ts">
+import { provideNotificationStore, type NotificationItem } from './notifications.svelte';
+import NotificationBell from './NotificationBell.svelte';
+
+type Api = { setNotifications: (items: NotificationItem[]) => void };
+
+let { onReady }: { onReady: (api: Api) => void } = $props();
+
+const store = provideNotificationStore();
+onReady({ setNotifications: store.setNotifications });
+</script>
+
+<NotificationBell />
diff --git a/frontend/src/lib/notification/notifications.svelte.spec.ts b/frontend/src/lib/notification/notifications.svelte.spec.ts
index 15345286..72ac98e3 100644
--- a/frontend/src/lib/notification/notifications.svelte.spec.ts
+++ b/frontend/src/lib/notification/notifications.svelte.spec.ts
@@ -39,19 +39,20 @@ vi.stubGlobal('EventSource', MockEventSource);
 const mockFetch = vi.fn();
 vi.stubGlobal('fetch', mockFetch);
 
-const { notificationStore, __resetForTest, __setNavigateForTest } =
-	await import('./notifications.svelte');
+const { createNotificationStore } = await import('./notifications.svelte');
 
-let navigateSpy: ReturnType<typeof vi.fn>;
+let store: ReturnType<typeof createNotificationStore>;
+let navigateSpy: ReturnType<typeof vi.fn<(url: string) => void>>;
 
 beforeEach(() => {
 	mockFetch.mockReset();
 	mockFetch.mockResolvedValue(new Response(JSON.stringify({ count: 0 }), { status: 200 }));
 	lastEventSource = null;
 	eventSourceCount = 0;
-	navigateSpy = vi.fn();
-	__setNavigateForTest(navigateSpy);
-	__resetForTest();
+	navigateSpy = vi.fn<(url: string) => void>();
+	// A fresh instance per test replaces the old __resetForTest() singleton reset.
+	store = createNotificationStore();
+	store.setNavigate(navigateSpy);
 });
 
 function makeNotification(overrides: Partial<NotificationItem> = {}): NotificationItem {
@@ -69,70 +70,70 @@ function makeNotification(overrides: Partial<NotificationItem> = {}): Notificati
 	};
 }
 
-describe('notificationStore (singleton)', () => {
+describe('notification store', () => {
 	it('opens a single EventSource across multiple init() calls', () => {
-		notificationStore.init();
-		notificationStore.init();
-		notificationStore.init();
+		store.init();
+		store.init();
+		store.init();
 
 		expect(eventSourceCount).toBe(1);
 	});
 
 	it('closes the EventSource only after every init() is matched with destroy()', () => {
-		notificationStore.init();
-		notificationStore.init();
+		store.init();
+		store.init();
 		const es = lastEventSource!;
 
-		notificationStore.destroy();
+		store.destroy();
 		expect(es.close).not.toHaveBeenCalled();
 
-		notificationStore.destroy();
+		store.destroy();
 		expect(es.close).toHaveBeenCalledTimes(1);
 	});
 
 	it('reopens a fresh EventSource after full teardown', () => {
-		notificationStore.init();
-		notificationStore.destroy();
-		notificationStore.init();
+		store.init();
+		store.destroy();
+		store.init();
 
 		expect(eventSourceCount).toBe(2);
 	});
 
 	it('SSE notification event prepends notification and increments unreadCount', () => {
-		notificationStore.init();
+		store.init();
 
 		const notification = makeNotification({ id: 'sse-1', read: false });
 		lastEventSource!.simulate('notification', JSON.stringify(notification));
 
-		expect(notificationStore.notifications[0].id).toBe('sse-1');
-		expect(notificationStore.unreadCount).toBe(1);
+		expect(store.notifications[0].id).toBe('sse-1');
+		expect(store.unreadCount).toBe(1);
 	});
 
 	it('optimisticMarkRead marks the notification read and decrements unreadCount without fetching', () => {
-		notificationStore.init();
+		store.init();
 		const notification = makeNotification({ id: 'sse-1', read: false });
 		lastEventSource!.simulate('notification', JSON.stringify(notification));
 		mockFetch.mockReset(); // clear the fetchUnreadCount call from init
 
-		notificationStore.optimisticMarkRead('sse-1');
+		store.optimisticMarkRead('sse-1');
 
-		expect(notificationStore.notifications[0].read).toBe(true);
-		expect(notificationStore.unreadCount).toBe(0);
+		expect(store.notifications[0].read).toBe(true);
+		expect(store.unreadCount).toBe(0);
 		expect(mockFetch).not.toHaveBeenCalled();
 	});
 
 	it('optimisticMarkRead on an already-read notification does not decrement unreadCount below 0', () => {
-		notificationStore.init();
+		store.init();
 		const notification = makeNotification({ id: 'sse-1', read: true });
 		lastEventSource!.simulate('notification', JSON.stringify(notification));
 
-		notificationStore.optimisticMarkRead('sse-1');
+		store.optimisticMarkRead('sse-1');
 
-		expect(notificationStore.unreadCount).toBe(0);
+		expect(store.unreadCount).toBe(0);
 	});
 
 	it('optimisticMarkAllRead resets unreadCount and marks all notifications read without fetching', () => {
-		notificationStore.init();
+		store.init();
 		lastEventSource!.simulate(
 			'notification',
 			JSON.stringify(makeNotification({ id: 'n1', read: false }))
@@ -143,18 +144,18 @@ describe('notificationStore (singleton)', () => {
 		);
 		mockFetch.mockReset();
 
-		notificationStore.optimisticMarkAllRead();
+		store.optimisticMarkAllRead();
 
-		expect(notificationStore.unreadCount).toBe(0);
-		expect(notificationStore.notifications.every((n) => n.read)).toBe(true);
+		expect(store.unreadCount).toBe(0);
+		expect(store.notifications.every((n) => n.read)).toBe(true);
 		expect(mockFetch).not.toHaveBeenCalled();
 	});
 });
 
-describe('notificationStore onerror handler', () => {
+describe('notification store onerror handler', () => {
 	it('redirects to /login when readyState is CLOSED and server returns 401', async () => {
 		mockFetch.mockResolvedValue(new Response(null, { status: 401 }));
-		notificationStore.init();
+		store.init();
 		const es = lastEventSource!;
 		es.readyState = MockEventSource.CLOSED;
 
@@ -164,7 +165,7 @@ describe('notificationStore onerror handler', () => {
 	});
 
 	it('does not redirect when readyState is CLOSED and session is still valid', async () => {
-		notificationStore.init();
+		store.init();
 		const es = lastEventSource!;
 		es.readyState = MockEventSource.CLOSED;
 
@@ -174,7 +175,7 @@ describe('notificationStore onerror handler', () => {
 	});
 
 	it('does not close or redirect before the error threshold when readyState is CONNECTING', async () => {
-		notificationStore.init();
+		store.init();
 		const es = lastEventSource!;
 		es.readyState = MockEventSource.CONNECTING;
 
@@ -187,7 +188,7 @@ describe('notificationStore onerror handler', () => {
 
 	it('closes and redirects after 3 consecutive CONNECTING errors when session returns 401', async () => {
 		mockFetch.mockResolvedValue(new Response(null, { status: 401 }));
-		notificationStore.init();
+		store.init();
 		const es = lastEventSource!;
 		es.readyState = MockEventSource.CONNECTING;
 
@@ -200,7 +201,7 @@ describe('notificationStore onerror handler', () => {
 	});
 
 	it('closes but does not redirect after threshold when session is still valid', async () => {
-		notificationStore.init();
+		store.init();
 		const es = lastEventSource!;
 		es.readyState = MockEventSource.CONNECTING;
 
@@ -213,7 +214,7 @@ describe('notificationStore onerror handler', () => {
 	});
 
 	it('resets error count after a successful reconnect (onopen)', async () => {
-		notificationStore.init();
+		store.init();
 		const es = lastEventSource!;
 		es.readyState = MockEventSource.CONNECTING;
 
diff --git a/frontend/src/lib/notification/notifications.svelte.ts b/frontend/src/lib/notification/notifications.svelte.ts
index 1e52cfe3..8d975d0e 100644
--- a/frontend/src/lib/notification/notifications.svelte.ts
+++ b/frontend/src/lib/notification/notifications.svelte.ts
@@ -1,121 +1,161 @@
+import { getContext, setContext } from 'svelte';
 import { type NotificationItem, parseNotificationEvent } from '$lib/notification/notifications';
 
 export type { NotificationItem };
 
-let notifications = $state<NotificationItem[]>([]);
-let unreadCount = $state(0);
-let eventSource: EventSource | null = null;
-let refCount = 0;
-let errorCount = 0;
-let navigate: (url: string) => void = (url) => {
-	window.location.href = url;
-};
+export const NOTIFICATION_KEY = Symbol('notification');
 
-async function fetchNotifications(): Promise<void> {
-	try {
-		const res = await fetch('/api/notifications?size=10');
-		if (res.ok) {
-			const data = await res.json();
-			notifications = data.content ?? [];
-		}
-	} catch (e) {
-		console.error('Failed to fetch notifications', e);
-	}
+export interface NotificationStore {
+	readonly notifications: NotificationItem[];
+	readonly unreadCount: number;
+	fetchNotifications(): Promise<void>;
+	fetchUnreadCount(): Promise<void>;
+	optimisticMarkRead(id: string): void;
+	optimisticMarkAllRead(): void;
+	init(): void;
+	destroy(): void;
+	/** Test-only: seed the notification list and derive the unread count. */
+	setNotifications(items: NotificationItem[]): void;
+	/** Test-only: override the 401 → redirect side-effect. */
+	setNavigate(fn: (url: string) => void): void;
 }
 
-async function fetchUnreadCount(): Promise<void> {
-	try {
-		const res = await fetch('/api/notifications/unread-count');
-		if (res.ok) {
-			const data = await res.json();
-			unreadCount = data.count;
-		}
-	} catch (e) {
-		console.error('Failed to fetch unread count', e);
-	}
-}
-
-function optimisticMarkRead(id: string): void {
-	const notification = notifications.find((n) => n.id === id);
-	if (notification && !notification.read) {
-		notification.read = true;
-		unreadCount = Math.max(0, unreadCount - 1);
-	}
-}
-
-function optimisticMarkAllRead(): void {
-	for (const n of notifications) {
-		n.read = true;
-	}
-	unreadCount = 0;
-}
-
-function init(): void {
-	refCount += 1;
-	if (refCount > 1) return;
-
-	fetchUnreadCount();
-	eventSource = new EventSource('/api/notifications/stream');
-	eventSource.addEventListener('notification', (e) => {
-		const notification = parseNotificationEvent((e as MessageEvent).data);
-		if (!notification) return;
-		notifications = [notification, ...notifications];
-		if (!notification.read) unreadCount += 1;
-	});
-	eventSource.onopen = () => {
-		fetchUnreadCount();
-		errorCount = 0;
+export function createNotificationStore(): NotificationStore {
+	let notifications = $state<NotificationItem[]>([]);
+	let unreadCount = $state(0);
+	let eventSource: EventSource | null = null;
+	let refCount = 0;
+	let errorCount = 0;
+	let navigate: (url: string) => void = (url) => {
+		window.location.href = url;
 	};
-	eventSource.onerror = async () => {
-		if (eventSource?.readyState === EventSource.CLOSED) {
-			const res = await fetch('/api/notifications/unread-count');
-			if (res.status === 401) navigate('/login');
-			return;
+
+	async function fetchNotifications(): Promise<void> {
+		try {
+			const res = await fetch('/api/notifications?size=10');
+			if (res.ok) {
+				const data = await res.json();
+				notifications = data.content ?? [];
+			}
+		} catch (e) {
+			console.error('Failed to fetch notifications', e);
 		}
-		errorCount += 1;
-		if (errorCount >= 3) {
+	}
+
+	async function fetchUnreadCount(): Promise<void> {
+		try {
+			const res = await fetch('/api/notifications/unread-count');
+			if (res.ok) {
+				const data = await res.json();
+				unreadCount = data.count;
+			}
+		} catch (e) {
+			console.error('Failed to fetch unread count', e);
+		}
+	}
+
+	function optimisticMarkRead(id: string): void {
+		const notification = notifications.find((n) => n.id === id);
+		if (notification && !notification.read) {
+			notification.read = true;
+			unreadCount = Math.max(0, unreadCount - 1);
+		}
+	}
+
+	function optimisticMarkAllRead(): void {
+		for (const n of notifications) {
+			n.read = true;
+		}
+		unreadCount = 0;
+	}
+
+	function init(): void {
+		refCount += 1;
+		if (refCount > 1) return;
+
+		fetchUnreadCount();
+		eventSource = new EventSource('/api/notifications/stream');
+		eventSource.addEventListener('notification', (e) => {
+			const notification = parseNotificationEvent((e as MessageEvent).data);
+			if (!notification) return;
+			notifications = [notification, ...notifications];
+			if (!notification.read) unreadCount += 1;
+		});
+		eventSource.onopen = () => {
+			fetchUnreadCount();
+			errorCount = 0;
+		};
+		eventSource.onerror = async () => {
+			if (eventSource?.readyState === EventSource.CLOSED) {
+				const res = await fetch('/api/notifications/unread-count');
+				if (res.status === 401) navigate('/login');
+				return;
+			}
+			errorCount += 1;
+			if (errorCount >= 3) {
+				eventSource?.close();
+				eventSource = null;
+				errorCount = 0;
+				const res = await fetch('/api/notifications/unread-count');
+				if (res.status === 401) navigate('/login');
+			}
+		};
+	}
+
+	function destroy(): void {
+		if (refCount === 0) return;
+		refCount -= 1;
+		if (refCount === 0) {
 			eventSource?.close();
 			eventSource = null;
-			errorCount = 0;
-			const res = await fetch('/api/notifications/unread-count');
-			if (res.status === 401) navigate('/login');
+		}
+	}
+
+	return {
+		get notifications() {
+			return notifications;
+		},
+		get unreadCount() {
+			return unreadCount;
+		},
+		fetchNotifications,
+		fetchUnreadCount,
+		optimisticMarkRead,
+		optimisticMarkAllRead,
+		init,
+		destroy,
+		setNotifications(items: NotificationItem[]): void {
+			notifications = items;
+			unreadCount = items.filter((n) => !n.read).length;
+		},
+		setNavigate(fn: (url: string) => void): void {
+			navigate = fn;
 		}
 	};
 }
 
-function destroy(): void {
-	if (refCount === 0) return;
-	refCount -= 1;
-	if (refCount === 0) {
-		eventSource?.close();
-		eventSource = null;
+/**
+ * Create a notification store and put it on the context. Call once high in the
+ * tree (root +layout.svelte). Descendants read it via getNotificationStore().
+ */
+export function provideNotificationStore(): NotificationStore {
+	const store = createNotificationStore();
+	setContext(NOTIFICATION_KEY, store);
+	return store;
+}
+
+export function getNotificationStore(): NotificationStore {
+	let store: NotificationStore | undefined;
+	try {
+		store = getContext<NotificationStore>(NOTIFICATION_KEY);
+	} catch {
+		throw new Error(
+			'NotificationStore not found — call provideNotificationStore() in +layout.svelte'
+		);
 	}
+	if (!store)
+		throw new Error(
+			'NotificationStore not found — call provideNotificationStore() in +layout.svelte'
+		);
+	return store;
 }
-
-export function __resetForTest(): void {
-	eventSource?.close();
-	eventSource = null;
-	refCount = 0;
-	errorCount = 0;
-	notifications = [];
-	unreadCount = 0;
-}
-
-export function __setNavigateForTest(fn: (url: string) => void): void {
-	navigate = fn;
-}
-
-export const notificationStore = {
-	get notifications() {
-		return notifications;
-	},
-	get unreadCount() {
-		return unreadCount;
-	},
-	fetchNotifications,
-	fetchUnreadCount,
-	optimisticMarkRead,
-	optimisticMarkAllRead,
-	init,
-	destroy
-};
diff --git a/frontend/src/routes/+layout.svelte b/frontend/src/routes/+layout.svelte
index 136eb060..1ca23440 100644
--- a/frontend/src/routes/+layout.svelte
+++ b/frontend/src/routes/+layout.svelte
@@ -10,6 +10,7 @@ import AppNav from './AppNav.svelte';
 import UserMenu from './UserMenu.svelte';
 import ConfirmDialog from '$lib/shared/primitives/ConfirmDialog.svelte';
 import { provideConfirmService } from '$lib/shared/services/confirm.svelte';
+import { provideNotificationStore } from '$lib/notification/notifications.svelte';
 import { bulkSelectionStore } from '$lib/document/bulkSelection.svelte';
 
 let { children, data } = $props();
@@ -18,6 +19,11 @@ let { children, data } = $props();
 // ConfirmDialog below reads it via getConfirmService() and renders the <dialog>.
 provideConfirmService();
 
+// Provide the notification store to the tree. NotificationBell (header) and the
+// Chronik page read it via getNotificationStore(); the bell drives the SSE
+// lifecycle through init()/destroy() on mount.
+provideNotificationStore();
+
 // Auto-clear the bulk-selection store when the user leaves the routes that
 // surface the BulkSelectionBar. Without this the selection silently follows
 // the user to /persons / /admin etc. and reappears as a stale 3-doc count
diff --git a/frontend/src/routes/aktivitaeten/+page.svelte b/frontend/src/routes/aktivitaeten/+page.svelte
index 7246e51e..06a0ff6b 100644
--- a/frontend/src/routes/aktivitaeten/+page.svelte
+++ b/frontend/src/routes/aktivitaeten/+page.svelte
@@ -3,7 +3,10 @@ import { onMount, onDestroy } from 'svelte';
 import { goto } from '$app/navigation';
 import { page, navigating } from '$app/state';
 import * as m from '$lib/paraglide/messages.js';
-import { notificationStore, type NotificationItem } from '$lib/notification/notifications.svelte';
+import {
+	getNotificationStore,
+	type NotificationItem
+} from '$lib/notification/notifications.svelte';
 import ChronikFuerDichBox from '$lib/activity/ChronikFuerDichBox.svelte';
 import ChronikFilterPills from '$lib/activity/ChronikFilterPills.svelte';
 import ChronikTimeline from '$lib/activity/ChronikTimeline.svelte';
@@ -26,9 +29,11 @@ interface Props {
 
 const { data }: Props = $props();
 
-// Prefer the live SSE singleton for unread items so newly arriving mentions
+const notificationStore = getNotificationStore();
+
+// Prefer the live SSE store for unread items so newly arriving mentions
 // prepend without a reload. On first mount, seed from the server-loaded unread
-// set if the singleton hasn't populated yet.
+// set if the store hasn't populated yet.
 onMount(() => {
 	notificationStore.init();
 });
@@ -59,7 +64,7 @@ const seedUnread = $derived<NotificationItem[]>(
 		}))
 );
 
-// If the singleton has any data (including zero after mark-all), trust it;
+// If the store has any data (including zero after mark-all), trust it;
 // otherwise fall back to the SSR-seeded unread set.
 const unread = $derived<NotificationItem[]>(
 	notificationStore.notifications.length > 0 ? liveUnread : seedUnread
diff --git a/frontend/src/routes/aktivitaeten/page.svelte.test.ts b/frontend/src/routes/aktivitaeten/page.svelte.test.ts
index def1980f..e9b90c4e 100644
--- a/frontend/src/routes/aktivitaeten/page.svelte.test.ts
+++ b/frontend/src/routes/aktivitaeten/page.svelte.test.ts
@@ -1,6 +1,7 @@
-import { describe, it, expect, vi, afterEach } from 'vitest';
+import { describe, it, expect, vi, afterEach, beforeEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
+import { createNotificationStore, NOTIFICATION_KEY } from '$lib/notification/notifications.svelte';
 
 const mockNavigating = { type: null };
 const mockPage = { url: new URL('http://localhost/aktivitaeten') };
@@ -28,19 +29,35 @@ vi.mock('$app/navigation', () => ({
 	onNavigate: () => () => {}
 }));
 
-vi.mock('$lib/notification/notifications.svelte', () => ({
-	notificationStore: {
-		notifications: [],
-		init: vi.fn(),
-		destroy: vi.fn(),
-		markRead: vi.fn(),
-		markAllRead: vi.fn()
-	}
-}));
+// The Chronik page's onMount calls store.init(), opening an EventSource and
+// fetching the unread count. Stub both so no real network / 401 → /login fires.
+class NoopEventSource {
+	static CLOSED = 2;
+	readyState = 0;
+	onopen: (() => void) | null = null;
+	onerror: (() => void) | null = null;
+	addEventListener() {}
+	close() {}
+}
+
+beforeEach(() => {
+	vi.stubGlobal('EventSource', NoopEventSource);
+	vi.stubGlobal(
+		'fetch',
+		vi
+			.fn()
+			.mockResolvedValue(new Response(JSON.stringify({ count: 0, content: [] }), { status: 200 }))
+	);
+});
 
 const { default: AktivitaetenPage } = await import('./+page.svelte');
 
-afterEach(cleanup);
+afterEach(() => {
+	cleanup();
+	vi.unstubAllGlobals();
+});
+
+const notificationContext = () => new Map([[NOTIFICATION_KEY, createNotificationStore()]]);
 
 const baseData = (overrides: Record<string, unknown> = {}) => ({
 	filter: 'alle' as const,
@@ -52,13 +69,16 @@ const baseData = (overrides: Record<string, unknown> = {}) => ({
 
 describe('aktivitaeten page', () => {
 	it('renders the page heading', async () => {
-		render(AktivitaetenPage, { props: { data: baseData() } });
+		render(AktivitaetenPage, { context: notificationContext(), props: { data: baseData() } });
 
 		await expect.element(page.getByRole('heading', { name: /aktivitäten/i })).toBeVisible();
 	});
 
 	it('renders the error card when loadError is "activity"', async () => {
-		render(AktivitaetenPage, { props: { data: baseData({ loadError: 'activity' }) } });
+		render(AktivitaetenPage, {
+			context: notificationContext(),
+			props: { data: baseData({ loadError: 'activity' }) }
+		});
 
 		// ChronikErrorCard renders some retry mechanism
 		const main = document.querySelector('main');
@@ -69,7 +89,7 @@ describe('aktivitaeten page', () => {
 	});
 
 	it('renders the FuerDichBox and FilterPills when loadError is null', async () => {
-		render(AktivitaetenPage, { props: { data: baseData() } });
+		render(AktivitaetenPage, { context: notificationContext(), props: { data: baseData() } });
 
 		// FuerDichBox shows the inbox-zero state when no unread
 		const fuerDich = document.querySelector('[data-testid="chronik-inbox-zero"]');
@@ -81,7 +101,7 @@ describe('aktivitaeten page', () => {
 	});
 
 	it('renders the first-run empty state when activityFeed is empty', async () => {
-		render(AktivitaetenPage, { props: { data: baseData() } });
+		render(AktivitaetenPage, { context: notificationContext(), props: { data: baseData() } });
 
 		const empty = document.querySelector('[data-testid="chronik-empty-state"]');
 		expect(empty?.getAttribute('data-variant')).toBe('first-run');
@@ -89,6 +109,7 @@ describe('aktivitaeten page', () => {
 
 	it('renders the filter-empty empty state when feed has items but filter rules out all', async () => {
 		render(AktivitaetenPage, {
+			context: notificationContext(),
 			props: {
 				data: baseData({
 					filter: 'fuer-dich' as const,
@@ -114,6 +135,7 @@ describe('aktivitaeten page', () => {
 
 	it('renders the timeline when displayFeed is non-empty', async () => {
 		render(AktivitaetenPage, {
+			context: notificationContext(),
 			props: {
 				data: baseData({
 					filter: 'alle' as const,
@@ -142,6 +164,7 @@ describe('aktivitaeten page', () => {
 
 	it('renders without crashing when filter is set to a non-default value', async () => {
 		render(AktivitaetenPage, {
+			context: notificationContext(),
 			props: { data: baseData({ filter: 'transkription' as const }) }
 		});