diff --git a/apps/dashboard/src/app/notifications.css b/apps/dashboard/src/app/notifications.css
index 203362d..1a33a59 100644
--- a/apps/dashboard/src/app/notifications.css
+++ b/apps/dashboard/src/app/notifications.css
@@ -43,7 +43,7 @@ a.notification-entry:hover { background: var(--surface); }
 .notification-empty > span { display: grid; place-items: center; width: 3.25rem; height: 3.25rem; margin-bottom: .9rem; color: var(--accent); background: var(--accent-dark); border: 1px solid #28593d; border-radius: 1rem; }
 .notification-empty strong { margin-bottom: .35rem; font-size: 1rem; }
 .notification-empty p { max-width: 18rem; margin: 0; color: var(--muted); font-size: .82rem; line-height: 1.5; }
-.toast-stack { position: fixed; right: 1rem; bottom: 1rem; z-index: 75; display: grid; gap: .65rem; width: min(24rem, calc(100% - 2rem)); pointer-events: none; }
+.toast-stack { position: fixed; right: 1rem; bottom: 1rem; z-index: 75; display: grid; gap: .65rem; width: min(24rem, calc(100% - 2rem)); max-height: calc(100vh - 2rem); overflow-y: auto; pointer-events: none; }
 .notification-toast { position: relative; overflow: hidden; background: #15221c; border: 1px solid #355044; border-radius: .85rem; box-shadow: 0 1rem 3rem rgba(0, 0, 0, .4); pointer-events: auto; animation: notification-arrive 220ms ease-out both; }
 .notification-toast.warning { background: #282112; border-color: #5b4922; }
 .notification-toast.error { background: #2d1715; border-color: #69332e; }
diff --git a/apps/dashboard/src/app/notifications.tsx b/apps/dashboard/src/app/notifications.tsx
index 3d5860d..365e516 100644
--- a/apps/dashboard/src/app/notifications.tsx
+++ b/apps/dashboard/src/app/notifications.tsx
@@ -168,6 +168,34 @@ export function notificationForEvent(event: DashboardEvent): NotificationDraft |
   }
 }
 
+/**
+ * Toasts interrupt the operator, so reserve them for inbound activity and
+ * states that need attention. Routine lifecycle and successful sync events
+ * remain available in the notification centre without producing a pop-up.
+ */
+export function shouldToastForEvent(event: DashboardEvent): boolean {
+  switch (event.type) {
+    case 'reply.received':
+    case 'media.received':
+    case 'message.failed':
+    case 'sync.failed':
+      return true;
+    case 'bot.status.changed':
+      return event.payload.status === 'stopped';
+    case 'rate-limit.changed':
+      return event.payload.limited;
+    case 'reddit.session.changed':
+      return ['expired', 'logged-out', 'error'].includes(event.payload.status);
+    case 'message.sent':
+    case 'conversation.updated':
+    case 'sync.started':
+    case 'sync.progress':
+    case 'sync.completed':
+    case 'log.created':
+      return false;
+  }
+}
+
 function loadNotifications(): NotificationItem[] {
   const storage = notificationStorage();
   if (!storage) return [];
@@ -221,20 +249,13 @@ export function NotificationProvider({ children, realtime: realtimeOverride }: N
     setNotifications((current) => current.some((entry) => entry.id === item.id)
       ? current
       : [item, ...current].slice(0, MAX_NOTIFICATIONS));
-    setToasts((current) => current.some((entry) => entry.id === item.id)
-      ? current
-      : [...current, item].slice(-3));
+    if (shouldToastForEvent(event)) {
+      setToasts((current) => current.some((entry) => entry.id === item.id)
+        ? current
+        : [...current, item]);
+    }
   }), [realtime]);
 
-  useEffect(() => {
-    if (toasts.length === 0) return undefined;
-    const timers = toasts.map((toast) => globalThis.setTimeout(
-      () => dismissToast(toast.id),
-      toast.tone === 'error' ? 8_000 : 5_000,
-    ));
-    return () => timers.forEach((timer) => globalThis.clearTimeout(timer));
-  }, [dismissToast, toasts]);
-
   useEffect(() => {
     function closeOnEscape(event: KeyboardEvent): void {
       if (event.key === 'Escape') setOpen(false);
diff --git a/docs/frontend.md b/docs/frontend.md
index 13e6460..62f1f82 100644
--- a/docs/frontend.md
+++ b/docs/frontend.md
@@ -63,7 +63,7 @@ Rules:
 - Duplicate/replayed events must be harmless.
 - A disconnected stream marks data stale but does not blank useful cached content.
 - Invalid event payloads are contained and repaired with a snapshot refresh.
-- User-triggered outcomes may create toasts; durable/history-worthy events also appear in the notification center/activity views.
+- The notification centre retains useful lifecycle history, including successful syncs. Sticky toasts are reserved for inbound replies/media and attention-worthy failures or runtime/account states; they remain visible until the operator dismisses them.
 - Raw technical logs belong in Operations, not as general user notifications.
 
 ## Authentication and privacy
diff --git a/tests/dashboard/notifications.test.tsx b/tests/dashboard/notifications.test.tsx
index 2f4ddd7..5f62366 100644
--- a/tests/dashboard/notifications.test.tsx
+++ b/tests/dashboard/notifications.test.tsx
@@ -11,6 +11,7 @@ import {
   NotificationProvider,
   NotificationViewport,
   notificationForEvent,
+  shouldToastForEvent,
 } from '../../apps/dashboard/src/app/notifications.js';
 
 class FakeRealtime {
@@ -28,7 +29,9 @@ class FakeRealtime {
 
 afterEach(() => {
   cleanup();
+  globalThis.localStorage.clear();
   vi.restoreAllMocks();
+  vi.useRealTimers();
 });
 
 describe('dashboard notifications', () => {
@@ -90,4 +93,57 @@ describe('dashboard notifications', () => {
     await user.click(within(centre).getByRole('button', { name: 'Clear all' }));
     expect(within(centre).getByText('All quiet')).toBeInTheDocument();
   });
+
+  it('keeps routine sync completions in the notification centre without showing a toast', async () => {
+    const realtime = new FakeRealtime();
+    const user = userEvent.setup();
+    render(
+      <MemoryRouter>
+        <NotificationProvider realtime={realtime}>
+          <NotificationBell />
+          <NotificationViewport />
+        </NotificationProvider>
+      </MemoryRouter>,
+    );
+
+    const syncEvent: DashboardEvent = {
+      id: 'sync-1',
+      occurredAt: '2026-08-09T09:30:00.000Z',
+      type: 'sync.completed',
+      payload: { syncId: 'conversation-sync-1', kind: 'conversations', processed: 12 },
+    };
+    expect(shouldToastForEvent(syncEvent)).toBe(false);
+    act(() => realtime.emit(syncEvent));
+
+    expect(screen.queryByRole('status')).not.toBeInTheDocument();
+    await user.click(screen.getByRole('button', { name: 'Notifications, 1 unread' }));
+    expect(within(screen.getByLabelText('Notifications', { selector: 'aside' })).getByText('Conversations sync complete'))
+      .toBeInTheDocument();
+  });
+
+  it('keeps important event toasts visible until they are dismissed', async () => {
+    vi.useFakeTimers();
+    const realtime = new FakeRealtime();
+    render(
+      <MemoryRouter>
+        <NotificationProvider realtime={realtime}>
+          <NotificationViewport />
+        </NotificationProvider>
+      </MemoryRouter>,
+    );
+
+    act(() => realtime.emit({
+      id: 'media-1',
+      occurredAt: '2026-08-09T09:30:00.000Z',
+      type: 'media.received',
+      payload: { conversationId: 'conversation-1', sender: 'alice', count: 1 },
+    }));
+    expect(screen.getByRole('status')).toHaveTextContent('Image received from u/alice');
+
+    act(() => vi.advanceTimersByTime(60_000));
+    expect(screen.getByRole('status')).toBeInTheDocument();
+
+    act(() => screen.getByRole('button', { name: 'Dismiss Image received from u/alice' }).click());
+    expect(screen.queryByRole('status')).not.toBeInTheDocument();
+  });
 });