diff --git a/ui/src/api/queries/alerts.test.tsx b/ui/src/api/queries/alerts.test.tsx
new file mode 100644
index 00000000..7ae91516
--- /dev/null
+++ b/ui/src/api/queries/alerts.test.tsx
@@ -0,0 +1,73 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { renderHook, waitFor } from '@testing-library/react';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import type { ReactNode } from 'react';
+import { useEnvironmentStore } from '../environment-store';
+
+vi.mock('../client', () => ({
+  api: { GET: vi.fn(), POST: vi.fn() },
+}));
+
+import { api as apiClient } from '../client';
+import { useAlerts, useUnreadCount } from './alerts';
+
+function wrapper({ children }: { children: ReactNode }) {
+  const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  return <QueryClientProvider client={qc}>{children}</QueryClientProvider>;
+}
+
+describe('useAlerts', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    useEnvironmentStore.setState({ environment: 'dev' });
+  });
+
+  it('fetches alerts for selected env and passes filter query params', async () => {
+    (apiClient.GET as any).mockResolvedValue({ data: [], error: null });
+    const { result } = renderHook(
+      () => useAlerts({ state: 'FIRING', severity: ['CRITICAL', 'WARNING'] }),
+      { wrapper },
+    );
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+    expect(apiClient.GET).toHaveBeenCalledWith(
+      '/environments/{envSlug}/alerts',
+      expect.objectContaining({
+        params: expect.objectContaining({
+          path: { envSlug: 'dev' },
+          query: expect.objectContaining({
+            state: ['FIRING'],
+            severity: ['CRITICAL', 'WARNING'],
+            limit: 100,
+          }),
+        }),
+      }),
+    );
+  });
+
+  it('does not fetch when no env is selected', () => {
+    useEnvironmentStore.setState({ environment: undefined });
+    const { result } = renderHook(() => useAlerts(), { wrapper });
+    expect(result.current.fetchStatus).toBe('idle');
+    expect(apiClient.GET).not.toHaveBeenCalled();
+  });
+});
+
+describe('useUnreadCount', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    useEnvironmentStore.setState({ environment: 'dev' });
+  });
+
+  it('returns the server payload unmodified', async () => {
+    (apiClient.GET as any).mockResolvedValue({
+      data: { total: 3, bySeverity: { CRITICAL: 1, WARNING: 2, INFO: 0 } },
+      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 },
+    });
+  });
+});
diff --git a/ui/src/api/queries/alerts.ts b/ui/src/api/queries/alerts.ts
new file mode 100644
index 00000000..d2541c3d
--- /dev/null
+++ b/ui/src/api/queries/alerts.ts
@@ -0,0 +1,168 @@
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import type { components } from '../schema';
+import { apiClient, useSelectedEnv } from './alertMeta';
+
+export type AlertDto = components['schemas']['AlertDto'];
+export type UnreadCountResponse = components['schemas']['UnreadCountResponse'];
+
+type AlertState = NonNullable<AlertDto['state']>;
+type AlertSeverity = NonNullable<AlertDto['severity']>;
+
+export interface AlertsFilter {
+  state?: AlertState | AlertState[];
+  severity?: AlertSeverity | AlertSeverity[];
+  ruleId?: string;
+  limit?: number;
+}
+
+function toArray<T>(v: T | T[] | undefined): T[] | undefined {
+  if (v === undefined) return undefined;
+  return Array.isArray(v) ? v : [v];
+}
+
+// NOTE ON TYPES: the generated OpenAPI schema for env-scoped alert endpoints
+// emits `path?: never` plus a `query.env: Environment` parameter because the
+// server resolves the env via the `@EnvPath` argument resolver, which the
+// OpenAPI scanner does not recognise as a path variable. At runtime the URL
+// template `{envSlug}` is substituted from `params.path.envSlug` by
+// openapi-fetch regardless of what the TS types say; we therefore cast the
+// call options to `any` to bypass the generated type oddity.
+
+/** List alert instances in the current env. Polls every 30s (pauses in background). */
+export function useAlerts(filter: AlertsFilter = {}) {
+  const env = useSelectedEnv();
+  return useQuery({
+    queryKey: ['alerts', env, filter],
+    enabled: !!env,
+    refetchInterval: 30_000,
+    refetchIntervalInBackground: false,
+    queryFn: async () => {
+      if (!env) throw new Error('no env');
+      const { data, error } = await apiClient.GET(
+        '/environments/{envSlug}/alerts',
+        {
+          params: {
+            path: { envSlug: env },
+            query: {
+              state: toArray(filter.state),
+              severity: toArray(filter.severity),
+              ruleId: filter.ruleId,
+              limit: filter.limit ?? 100,
+            },
+          },
+        } as any,
+      );
+      if (error) throw error;
+      return data as AlertDto[];
+    },
+  });
+}
+
+/** Fetch a single alert instance by id. */
+export function useAlert(id: string | undefined) {
+  const env = useSelectedEnv();
+  return useQuery({
+    queryKey: ['alerts', env, 'detail', id],
+    enabled: !!env && !!id,
+    queryFn: async () => {
+      if (!env || !id) throw new Error('no env/id');
+      const { data, error } = await apiClient.GET(
+        '/environments/{envSlug}/alerts/{id}',
+        {
+          params: { path: { envSlug: env, id } },
+        } as any,
+      );
+      if (error) throw error;
+      return data as AlertDto;
+    },
+  });
+}
+
+/** Unread alert count for the current env. Polls every 30s (pauses in background). */
+export function useUnreadCount() {
+  const env = useSelectedEnv();
+  return useQuery({
+    queryKey: ['alerts', env, 'unread-count'],
+    enabled: !!env,
+    refetchInterval: 30_000,
+    refetchIntervalInBackground: false,
+    queryFn: async () => {
+      if (!env) throw new Error('no env');
+      const { data, error } = await apiClient.GET(
+        '/environments/{envSlug}/alerts/unread-count',
+        {
+          params: { path: { envSlug: env } },
+        } as any,
+      );
+      if (error) throw error;
+      return data as UnreadCountResponse;
+    },
+  });
+}
+
+/** Acknowledge a single alert instance. */
+export function useAckAlert() {
+  const env = useSelectedEnv();
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: async (id: string) => {
+      if (!env) throw new Error('no env');
+      const { data, error } = await apiClient.POST(
+        '/environments/{envSlug}/alerts/{id}/ack',
+        {
+          params: { path: { envSlug: env, id } },
+        } as any,
+      );
+      if (error) throw error;
+      return data as AlertDto;
+    },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['alerts', env] });
+    },
+  });
+}
+
+/** Mark a single alert instance as read (inbox semantics). */
+export function useMarkAlertRead() {
+  const env = useSelectedEnv();
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: async (id: string) => {
+      if (!env) throw new Error('no env');
+      const { error } = await apiClient.POST(
+        '/environments/{envSlug}/alerts/{id}/read',
+        {
+          params: { path: { envSlug: env, id } },
+        } as any,
+      );
+      if (error) throw error;
+    },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['alerts', env] });
+      qc.invalidateQueries({ queryKey: ['alerts', env, 'unread-count'] });
+    },
+  });
+}
+
+/** Mark a batch of alert instances as read. */
+export function useBulkReadAlerts() {
+  const env = useSelectedEnv();
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: async (ids: string[]) => {
+      if (!env) throw new Error('no env');
+      const { error } = await apiClient.POST(
+        '/environments/{envSlug}/alerts/bulk-read',
+        {
+          params: { path: { envSlug: env } },
+          body: { alertInstanceIds: ids },
+        } as any,
+      );
+      if (error) throw error;
+    },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['alerts', env] });
+      qc.invalidateQueries({ queryKey: ['alerts', env, 'unread-count'] });
+    },
+  });
+}