diff --git a/core/test/agents/active_streaming_tool_test.ts b/core/test/agents/active_streaming_tool_test.ts
new file mode 100644
index 00000000..e756022a
--- /dev/null
+++ b/core/test/agents/active_streaming_tool_test.ts
@@ -0,0 +1,51 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {describe, expect, it} from 'vitest';
+import {ActiveStreamingTool} from '../../src/agents/active_streaming_tool.js';
+import {LiveRequestQueue} from '../../src/agents/live_request_queue.js';
+
+describe('ActiveStreamingTool', () => {
+  it('should have undefined fields when constructed with no params', () => {
+    const tool = new ActiveStreamingTool();
+    expect(tool.task).toBeUndefined();
+    expect(tool.stream).toBeUndefined();
+  });
+
+  it('should set task when constructed with only task param', () => {
+    const task = Promise.resolve();
+    const tool = new ActiveStreamingTool({task});
+    expect(tool.task).toBe(task);
+    expect(tool.stream).toBeUndefined();
+  });
+
+  it('should set stream when constructed with only stream param', () => {
+    const stream = new LiveRequestQueue();
+    const tool = new ActiveStreamingTool({stream});
+    expect(tool.task).toBeUndefined();
+    expect(tool.stream).toBe(stream);
+  });
+
+  it('should set both task and stream when both params are provided', () => {
+    const task = Promise.resolve();
+    const stream = new LiveRequestQueue();
+    const tool = new ActiveStreamingTool({task, stream});
+    expect(tool.task).toBe(task);
+    expect(tool.stream).toBe(stream);
+  });
+
+  it('should allow fields to be read independently after construction', () => {
+    const task = new Promise<void>((resolve) => setTimeout(resolve, 100));
+    const stream = new LiveRequestQueue();
+    const tool = new ActiveStreamingTool({task, stream});
+
+    const readTask = tool.task;
+    const readStream = tool.stream;
+    expect(readTask).toBe(task);
+    expect(readStream).toBe(stream);
+    expect(readStream).toBeInstanceOf(LiveRequestQueue);
+  });
+});