diff --git a/app/src/hooks/useConsciousItems.test.tsx b/app/src/hooks/useConsciousItems.test.tsx
new file mode 100644
index 000000000..3e5656811
--- /dev/null
+++ b/app/src/hooks/useConsciousItems.test.tsx
@@ -0,0 +1,80 @@
+import { act, renderHook } from '@testing-library/react';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+import { useConsciousItems } from './useConsciousItems';
+
+const mockConsciousLoopRun = vi.fn();
+const mockMemoryQueryNamespace = vi.fn();
+
+vi.mock('../utils/tauriCommands', async importOriginal => {
+  const actual = await importOriginal<typeof import('../utils/tauriCommands')>();
+  return {
+    ...actual,
+    isTauri: () => true,
+    consciousLoopRun: (...args: unknown[]) => mockConsciousLoopRun(...args),
+    memoryQueryNamespace: (...args: unknown[]) => mockMemoryQueryNamespace(...args),
+  };
+});
+
+// `listen` resolves an unlisten fn but never fires events, so `isRunning` stays
+// false — modelling the window before the backend `conscious_loop:started`
+// event arrives, which is exactly where the duplicate-run race lived.
+vi.mock('@tauri-apps/api/event', () => ({ listen: vi.fn(() => Promise.resolve(() => {})) }));
+
+vi.mock('../lib/coreState/store', () => ({
+  getCoreStateSnapshot: () => ({ snapshot: { sessionToken: 'test-token' } }),
+}));
+
+vi.mock('../services/backendUrl', () => ({
+  getBackendUrl: () => Promise.resolve('http://localhost:9999'),
+}));
+
+describe('useConsciousItems · triggerAnalysis re-entry guard', () => {
+  beforeEach(() => {
+    mockConsciousLoopRun.mockReset();
+    mockMemoryQueryNamespace.mockReset();
+    mockMemoryQueryNamespace.mockResolvedValue({ text: '' });
+  });
+
+  it('does not start a second run while the first is in flight (before isRunning flips)', async () => {
+    let resolveRun: () => void = () => {};
+    mockConsciousLoopRun.mockImplementation(
+      () =>
+        new Promise<void>(resolve => {
+          resolveRun = resolve;
+        })
+    );
+
+    const { result } = renderHook(() => useConsciousItems());
+
+    // Two synchronous triggers within the pre-`started`-event window: the
+    // backend has not yet flipped `isRunning`, so only the synchronous ref
+    // guard can stop the duplicate.
+    await act(async () => {
+      void result.current.triggerAnalysis();
+      void result.current.triggerAnalysis();
+    });
+
+    expect(mockConsciousLoopRun).toHaveBeenCalledTimes(1);
+
+    // Settle the in-flight run so the ref releases for the next assertion.
+    await act(async () => {
+      resolveRun();
+    });
+  });
+
+  it('releases the guard after a run settles so a later run can start', async () => {
+    mockConsciousLoopRun.mockResolvedValue(undefined);
+
+    const { result } = renderHook(() => useConsciousItems());
+
+    await act(async () => {
+      await result.current.triggerAnalysis();
+    });
+    await act(async () => {
+      await result.current.triggerAnalysis();
+    });
+
+    expect(mockConsciousLoopRun).toHaveBeenCalledTimes(2);
+  });
+});
diff --git a/app/src/hooks/useConsciousItems.ts b/app/src/hooks/useConsciousItems.ts
index 073b73095..ca841885b 100644
--- a/app/src/hooks/useConsciousItems.ts
+++ b/app/src/hooks/useConsciousItems.ts
@@ -149,6 +149,11 @@ export function useConsciousItems(): UseConsciousItemsResult {
 
   // Prevent double-fetch on StrictMode double-mount
   const fetchingRef = useRef(false);
+  // Synchronous guard for triggerAnalysis: `isRunning` only flips true once the
+  // backend round-trips the `conscious_loop:started` event, leaving a window
+  // where a second synchronous call would pass the `isRunning` guard and fire a
+  // duplicate run. This ref closes that window immediately (mirrors fetchingRef).
+  const runningRef = useRef(false);
 
   const refresh = useCallback(async () => {
     if (!isTauri() || fetchingRef.current) return;
@@ -174,11 +179,14 @@ export function useConsciousItems(): UseConsciousItemsResult {
 
   const triggerAnalysis = useCallback(async () => {
     const authToken = getCoreStateSnapshot().snapshot.sessionToken;
-    if (!isTauri() || !authToken || isRunning) return;
+    if (!isTauri() || !authToken || isRunning || runningRef.current) return;
+    runningRef.current = true;
     try {
       await consciousLoopRun(authToken, await getBackendUrl());
     } catch (err) {
       console.warn('[conscious] Failed to trigger analysis:', err);
+    } finally {
+      runningRef.current = false;
     }
   }, [isRunning]);