diff --git a/ui/src/api/queries/alerts.test.tsx b/ui/src/api/queries/alerts.test.tsx
index 7ae91516..b8eb3e66 100644
--- a/ui/src/api/queries/alerts.test.tsx
+++ b/ui/src/api/queries/alerts.test.tsx
@@ -60,14 +60,11 @@ describe('useUnreadCount', () => {
 
   it('returns the server payload unmodified', async () => {
     (apiClient.GET as any).mockResolvedValue({
-      data: { total: 3, bySeverity: { CRITICAL: 1, WARNING: 2, INFO: 0 } },
+      data: { count: 3 },
       error: null,
     });
     const { result } = renderHook(() => useUnreadCount(), { wrapper });
     await waitFor(() => expect(result.current.isSuccess).toBe(true));
-    expect(result.current.data).toEqual({
-      total: 3,
-      bySeverity: { CRITICAL: 1, WARNING: 2, INFO: 0 },
-    });
+    expect(result.current.data).toEqual({ count: 3 });
   });
 });
diff --git a/ui/src/components/NotificationBell.tsx b/ui/src/components/NotificationBell.tsx
index d2b7738d..8c129e4a 100644
--- a/ui/src/components/NotificationBell.tsx
+++ b/ui/src/components/NotificationBell.tsx
@@ -2,7 +2,6 @@ import { Link } from 'react-router';
 import { Bell } from 'lucide-react';
 import { useUnreadCount } from '../api/queries/alerts';
 import { useSelectedEnv } from '../api/queries/alertMeta';
-import { usePageVisible } from '../hooks/usePageVisible';
 import css from './NotificationBell.module.css';
 
 /**
@@ -10,23 +9,13 @@ import css from './NotificationBell.module.css';
  * inbox and renders a badge with the unread-alert count for the currently
  * selected environment.
  *
- * Polling is driven by `useUnreadCount` (30s interval, paused in background
- * via TanStack Query's `refetchIntervalInBackground: false`). The
- * `usePageVisible` hook is retained as a defense-in-depth signal so future
- * UI behavior (e.g. animations, live-region updates) can key off visibility
- * without re-wiring the polling logic.
- *
- * TODO (spec §13): per-severity badge coloring — the backend
- * `UnreadCountResponse` currently exposes only a scalar `count` field. To
- * colour the badge by max unread severity (CRITICAL → error, WARNING →
- * amber, INFO → muted) the DTO must grow a `bySeverity` map; deferred to a
- * future task. Until then the badge uses a single `var(--error)` tint.
+ * Polling pause when the tab is hidden is handled by `useUnreadCount`'s
+ * `refetchIntervalInBackground: false`; no separate visibility subscription
+ * is needed. If per-severity coloring (spec §13) is re-introduced, the
+ * backend `UnreadCountResponse` must grow a `bySeverity` map.
  */
 export function NotificationBell() {
   const env = useSelectedEnv();
-  // Subscribe to visibility so the component re-renders on tab focus, even
-  // though the polling pause itself is handled inside useUnreadCount.
-  usePageVisible();
   const { data } = useUnreadCount();
 
   const count = data?.count ?? 0;