diff --git a/src/test/scenarios/orbitBulkEnqueue.scenario.test.ts b/src/test/scenarios/orbitBulkEnqueue.scenario.test.ts
new file mode 100644
index 00000000..4a50fe37
--- /dev/null
+++ b/src/test/scenarios/orbitBulkEnqueue.scenario.test.ts
@@ -0,0 +1,48 @@
+import { beforeEach, describe, expect, it, vi, type Mock } from 'vitest';
+import { usePlayerStore } from '@/features/playback/store/playerStore';
+import { registerOrbitRuntime } from '@/store/orbitRuntime';
+import { makeTracks } from '@/test/helpers/factories';
+import { resetAllStores } from '@/test/helpers/storeReset';
+
+// Scenario: orbit session × bulk enqueue. The real `enqueue` action routes a
+// multi-track enqueue through the orbitRuntime.bulkGuard seam and only commits the
+// tracks when the guard resolves true; a single track bypasses the guard entirely.
+// We inject a fake runtime and assert the observable queue outcome.
+
+const flush = () => new Promise((r) => setTimeout(r, 0));
+
+let bulkGuard: Mock<(count: number) => Promise<boolean>>;
+
+beforeEach(() => {
+  resetAllStores();
+  bulkGuard = vi.fn<(count: number) => Promise<boolean>>(async () => true);
+  registerOrbitRuntime({
+    getSnapshot: () => ({ role: 'host', phase: 'active', state: null }),
+    bulkGuard,
+  });
+});
+
+describe('orbit session × bulk enqueue', () => {
+  it('over-threshold + guard accepts → tracks enqueued', async () => {
+    bulkGuard.mockResolvedValue(true);
+    usePlayerStore.getState().enqueue(makeTracks(2));
+    await flush();
+    expect(bulkGuard).toHaveBeenCalledWith(2);
+    expect(usePlayerStore.getState().queueItems).toHaveLength(2);
+  });
+
+  it('over-threshold + guard rejects → nothing enqueued', async () => {
+    bulkGuard.mockResolvedValue(false);
+    usePlayerStore.getState().enqueue(makeTracks(2));
+    await flush();
+    expect(bulkGuard).toHaveBeenCalledWith(2);
+    expect(usePlayerStore.getState().queueItems).toHaveLength(0);
+  });
+
+  it('single track bypasses the guard and enqueues directly', async () => {
+    usePlayerStore.getState().enqueue(makeTracks(1));
+    await flush();
+    expect(bulkGuard).not.toHaveBeenCalled();
+    expect(usePlayerStore.getState().queueItems).toHaveLength(1);
+  });
+});