diff --git a/src/group-queue.test.ts b/src/group-queue.test.ts
index f236b22..75ef506 100644
--- a/src/group-queue.test.ts
+++ b/src/group-queue.test.ts
@@ -318,6 +318,66 @@ describe('GroupQueue', () => {
     await vi.advanceTimersByTimeAsync(10);
   });
 
+  it('sendMessage resets idleWaiting so a subsequent task enqueue does not preempt', async () => {
+    const fs = await import('fs');
+    let resolveProcess: () => void;
+
+    const processMessages = vi.fn(async () => {
+      await new Promise<void>((resolve) => {
+        resolveProcess = resolve;
+      });
+      return true;
+    });
+
+    queue.setProcessMessagesFn(processMessages);
+    queue.enqueueMessageCheck('group1@g.us');
+    await vi.advanceTimersByTimeAsync(10);
+    queue.registerProcess('group1@g.us', {} as any, 'container-1', 'test-group');
+
+    // Container becomes idle
+    queue.notifyIdle('group1@g.us');
+
+    // A new user message arrives — resets idleWaiting
+    queue.sendMessage('group1@g.us', 'hello');
+
+    // Task enqueued after message reset — should NOT preempt (agent is working)
+    const writeFileSync = vi.mocked(fs.default.writeFileSync);
+    writeFileSync.mockClear();
+
+    const taskFn = vi.fn(async () => {});
+    queue.enqueueTask('group1@g.us', 'task-1', taskFn);
+
+    const closeWrites = writeFileSync.mock.calls.filter(
+      (call) => typeof call[0] === 'string' && call[0].endsWith('_close'),
+    );
+    expect(closeWrites).toHaveLength(0);
+
+    resolveProcess!();
+    await vi.advanceTimersByTimeAsync(10);
+  });
+
+  it('sendMessage returns false for task containers so user messages queue up', async () => {
+    let resolveTask: () => void;
+
+    const taskFn = vi.fn(async () => {
+      await new Promise<void>((resolve) => {
+        resolveTask = resolve;
+      });
+    });
+
+    // Start a task (sets isTaskContainer = true)
+    queue.enqueueTask('group1@g.us', 'task-1', taskFn);
+    await vi.advanceTimersByTimeAsync(10);
+    queue.registerProcess('group1@g.us', {} as any, 'container-1', 'test-group');
+
+    // sendMessage should return false — user messages must not go to task containers
+    const result = queue.sendMessage('group1@g.us', 'hello');
+    expect(result).toBe(false);
+
+    resolveTask!();
+    await vi.advanceTimersByTimeAsync(10);
+  });
+
   it('preempts when idle arrives with pending tasks', async () => {
     const fs = await import('fs');
     let resolveProcess: () => void;