diff --git a/package-lock.json b/package-lock.json
index 9506990..13f9b64 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19,6 +19,7 @@
         "js-yaml": "^4.1.1",
         "ora": "^8.1.0",
         "tree-sitter-bash": "^0.25.1",
+        "uuid": "^13.0.0",
         "vscode-jsonrpc": "^8.2.1",
         "vscode-languageserver-protocol": "^3.17.5",
         "web-tree-sitter": "^0.25.10",
@@ -30,6 +31,7 @@
       "devDependencies": {
         "@types/js-yaml": "^4.0.9",
         "@types/node": "^22.0.0",
+        "@types/uuid": "^10.0.0",
         "@vitest/coverage-v8": "^4.0.15",
         "tsx": "^4.19.0",
         "typescript": "^5.6.0",
@@ -1354,6 +1356,13 @@
         "undici-types": "~6.21.0"
       }
     },
+    "node_modules/@types/uuid": {
+      "version": "10.0.0",
+      "resolved": "https://registry.npmjs.org/@types/uuid/-/uuid-10.0.0.tgz",
+      "integrity": "sha512-7gqG38EyHgyP1S+7+xomFtL+ZNHcKv6DwNaCZmJmo1vgMugyF3TCnXVg4t1uk89mLNwnLtnY3TpOpCOyp1/xHQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@vercel/oidc": {
       "version": "3.0.5",
       "resolved": "https://registry.npmjs.org/@vercel/oidc/-/oidc-3.0.5.tgz",
@@ -2882,6 +2891,19 @@
       "devOptional": true,
       "license": "MIT"
     },
+    "node_modules/uuid": {
+      "version": "13.0.0",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-13.0.0.tgz",
+      "integrity": "sha512-XQegIaBTVUjSHliKqcnFqYypAd4S+WCYt5NIeRs6w/UAry7z8Y9j5ZwRRL4kzq9U3sD6v+85er9FvkEaBpji2w==",
+      "funding": [
+        "https://github.com/sponsors/broofa",
+        "https://github.com/sponsors/ctavan"
+      ],
+      "license": "MIT",
+      "bin": {
+        "uuid": "dist-node/bin/uuid"
+      }
+    },
     "node_modules/vite": {
       "version": "7.2.7",
       "resolved": "https://registry.npmjs.org/vite/-/vite-7.2.7.tgz",
diff --git a/package.json b/package.json
index 35b7457..9944a9a 100644
--- a/package.json
+++ b/package.json
@@ -36,6 +36,7 @@
     "js-yaml": "^4.1.1",
     "ora": "^8.1.0",
     "tree-sitter-bash": "^0.25.1",
+    "uuid": "^13.0.0",
     "vscode-jsonrpc": "^8.2.1",
     "vscode-languageserver-protocol": "^3.17.5",
     "web-tree-sitter": "^0.25.10",
@@ -44,6 +45,7 @@
   "devDependencies": {
     "@types/js-yaml": "^4.0.9",
     "@types/node": "^22.0.0",
+    "@types/uuid": "^10.0.0",
     "@vitest/coverage-v8": "^4.0.15",
     "tsx": "^4.19.0",
     "typescript": "^5.6.0",
diff --git a/src/agent/index.ts b/src/agent/index.ts
index 505eb87..7d6c19f 100644
--- a/src/agent/index.ts
+++ b/src/agent/index.ts
@@ -21,6 +21,15 @@ export { AgentRegistry, agentRegistry } from './registry.js';
 // Executor
 export { AgentExecutor } from './executor.js';
 
+// Manager
+export {
+  AgentManager,
+  getAgentManager,
+  resetAgentManager,
+  type BackgroundAgent,
+  type BackgroundAgentStatus,
+} from './manager.js';
+
 // Permission Merger
 export {
   SYSTEM_DEFAULT_PERMISSION,
diff --git a/src/agent/manager.ts b/src/agent/manager.ts
new file mode 100644
index 0000000..37f821a
--- /dev/null
+++ b/src/agent/manager.ts
@@ -0,0 +1,249 @@
+import { v4 as uuidv4 } from 'uuid';
+import type { AgentConfig } from '../types/index.js';
+import type { AgentExecutionContext, AgentInfo } from './types.js';
+import { AgentExecutor } from './executor.js';
+import { ToolRegistry } from '../tools/registry.js';
+
+/**
+ * 后台 Agent 状态
+ */
+export type BackgroundAgentStatus = 'running' | 'completed' | 'failed';
+
+/**
+ * 后台 Agent 信息
+ */
+export interface BackgroundAgent {
+  /** Agent 唯一 ID */
+  id: string;
+  /** Agent 类型名称 */
+  agentName: string;
+  /** 任务描述 */
+  description: string;
+  /** 执行状态 */
+  status: BackgroundAgentStatus;
+  /** 任务提示词 */
+  prompt: string;
+  /** 开始时间 */
+  startedAt: Date;
+  /** 完成时间 */
+  completedAt?: Date;
+  /** 执行结果 */
+  result?: string;
+  /** 错误信息 */
+  error?: string;
+  /** 执行步数 */
+  steps?: number;
+}
+
+/**
+ * Agent 管理器
+ * 负责管理后台 Agent 的生命周期
+ */
+export class AgentManager {
+  private backgroundAgents = new Map<string, BackgroundAgent>();
+  private completionCallbacks = new Map<string, Array<() => void>>();
+
+  /**
+   * 启动后台 Agent
+   */
+  async runInBackground(
+    agentInfo: AgentInfo,
+    description: string,
+    prompt: string,
+    baseConfig: AgentConfig,
+    toolRegistry: ToolRegistry,
+    context: AgentExecutionContext
+  ): Promise<string> {
+    const agentId = uuidv4().substring(0, 8); // 短 ID
+
+    // 创建后台 Agent 记录
+    this.backgroundAgents.set(agentId, {
+      id: agentId,
+      agentName: agentInfo.name,
+      description,
+      status: 'running',
+      prompt,
+      startedAt: new Date(),
+    });
+
+    // 异步执行，不等待结果
+    this.executeAsync(agentId, agentInfo, prompt, baseConfig, toolRegistry, context);
+
+    return agentId;
+  }
+
+  /**
+   * 异步执行 Agent 任务
+   */
+  private async executeAsync(
+    agentId: string,
+    agentInfo: AgentInfo,
+    prompt: string,
+    baseConfig: AgentConfig,
+    toolRegistry: ToolRegistry,
+    context: AgentExecutionContext
+  ): Promise<void> {
+    try {
+      const executor = new AgentExecutor(agentInfo, baseConfig, toolRegistry);
+      const result = await executor.execute(prompt, {
+        ...context,
+        onStream: undefined, // 后台运行不使用流式输出
+      });
+
+      // 更新状态为完成
+      const agent = this.backgroundAgents.get(agentId);
+      if (agent) {
+        agent.status = result.success ? 'completed' : 'failed';
+        agent.completedAt = new Date();
+        agent.result = result.text;
+        agent.steps = result.steps;
+        if (!result.success) {
+          agent.error = result.error;
+        }
+      }
+    } catch (error) {
+      // 更新状态为失败
+      const agent = this.backgroundAgents.get(agentId);
+      if (agent) {
+        agent.status = 'failed';
+        agent.completedAt = new Date();
+        agent.error = error instanceof Error ? error.message : String(error);
+      }
+    }
+
+    // 触发等待回调
+    this.notifyCompletion(agentId);
+  }
+
+  /**
+   * 获取后台 Agent 状态
+   */
+  getAgent(agentId: string): BackgroundAgent | null {
+    return this.backgroundAgents.get(agentId) || null;
+  }
+
+  /**
+   * 获取 Agent 输出（支持阻塞等待）
+   */
+  async getAgentOutput(
+    agentId: string,
+    block: boolean = true,
+    timeoutSeconds: number = 150
+  ): Promise<BackgroundAgent | null> {
+    const agent = this.backgroundAgents.get(agentId);
+    if (!agent) {
+      return null;
+    }
+
+    // 如果已完成或不需要阻塞，直接返回
+    if (agent.status !== 'running' || !block) {
+      return agent;
+    }
+
+    // 阻塞等待完成
+    return this.waitForCompletion(agentId, timeoutSeconds);
+  }
+
+  /**
+   * 等待 Agent 完成
+   */
+  private waitForCompletion(
+    agentId: string,
+    timeoutSeconds: number
+  ): Promise<BackgroundAgent | null> {
+    return new Promise((resolve) => {
+      const agent = this.backgroundAgents.get(agentId);
+      if (!agent || agent.status !== 'running') {
+        resolve(agent || null);
+        return;
+      }
+
+      // 设置超时
+      const timeoutId = setTimeout(() => {
+        // 移除回调
+        const callbacks = this.completionCallbacks.get(agentId);
+        if (callbacks) {
+          const index = callbacks.indexOf(callback);
+          if (index > -1) {
+            callbacks.splice(index, 1);
+          }
+        }
+        resolve(this.backgroundAgents.get(agentId) || null);
+      }, timeoutSeconds * 1000);
+
+      // 注册完成回调
+      const callback = () => {
+        clearTimeout(timeoutId);
+        resolve(this.backgroundAgents.get(agentId) || null);
+      };
+
+      if (!this.completionCallbacks.has(agentId)) {
+        this.completionCallbacks.set(agentId, []);
+      }
+      this.completionCallbacks.get(agentId)!.push(callback);
+    });
+  }
+
+  /**
+   * 通知等待者任务已完成
+   */
+  private notifyCompletion(agentId: string): void {
+    const callbacks = this.completionCallbacks.get(agentId);
+    if (callbacks) {
+      for (const callback of callbacks) {
+        callback();
+      }
+      this.completionCallbacks.delete(agentId);
+    }
+  }
+
+  /**
+   * 列出所有后台 Agent
+   */
+  listAgents(): BackgroundAgent[] {
+    return Array.from(this.backgroundAgents.values());
+  }
+
+  /**
+   * 列出运行中的 Agent
+   */
+  listRunningAgents(): BackgroundAgent[] {
+    return this.listAgents().filter((a) => a.status === 'running');
+  }
+
+  /**
+   * 清理已完成的 Agent 记录
+   */
+  cleanup(maxAge: number = 3600000): void {
+    const now = Date.now();
+    for (const [id, agent] of this.backgroundAgents) {
+      if (
+        agent.status !== 'running' &&
+        agent.completedAt &&
+        now - agent.completedAt.getTime() > maxAge
+      ) {
+        this.backgroundAgents.delete(id);
+      }
+    }
+  }
+}
+
+// 单例实例
+let agentManager: AgentManager | null = null;
+
+/**
+ * 获取 AgentManager 单例
+ */
+export function getAgentManager(): AgentManager {
+  if (!agentManager) {
+    agentManager = new AgentManager();
+  }
+  return agentManager;
+}
+
+/**
+ * 重置 AgentManager（测试用）
+ */
+export function resetAgentManager(): void {
+  agentManager = null;
+}
diff --git a/src/tools/index.ts b/src/tools/index.ts
index c56e305..91e10e2 100644
--- a/src/tools/index.ts
+++ b/src/tools/index.ts
@@ -9,7 +9,7 @@ import { toolSearchTool } from './tool-search.js';
 import { todoReadTool, todoWriteTool } from './todo/index.js';
 
 // Task 工具（Agent 子任务）
-import { taskTool } from './task/index.js';
+import { taskTool, agentOutputTool } from './task/index.js';
 
 // 文件系统工具
 import {
@@ -51,6 +51,7 @@ const allToolsWithMetadata: ToolWithMetadata[] = [
   todoReadTool,
   todoWriteTool,
   taskTool,
+  agentOutputTool,
 
   // 文件系统工具 (deferLoading: true)
   readFileTool,
diff --git a/src/tools/task/agent_output.ts b/src/tools/task/agent_output.ts
new file mode 100644
index 0000000..b28c105
--- /dev/null
+++ b/src/tools/task/agent_output.ts
@@ -0,0 +1,132 @@
+import type { ToolWithMetadata } from '../types.js';
+import { getAgentManager } from '../../agent/manager.js';
+
+/**
+ * Agent Output 工具
+ * 用于获取后台 Agent 的执行结果
+ */
+export const agentOutputTool: ToolWithMetadata = {
+  name: 'agent_output',
+  description: `获取后台运行的 Agent 执行结果。
+
+当使用 task 工具的 run_in_background 参数启动后台 Agent 后，
+使用此工具查询执行状态和结果。
+
+使用示例:
+- 查询结果（阻塞等待）: agent_output({ agent_id: "abc123" })
+- 检查状态（不阻塞）: agent_output({ agent_id: "abc123", block: false })
+- 设置超时: agent_output({ agent_id: "abc123", timeout: 60 })`,
+  parameters: {
+    agent_id: {
+      type: 'string',
+      description: 'Agent ID（由 task 工具返回）',
+      required: true,
+    },
+    block: {
+      type: 'boolean',
+      description: '是否阻塞等待结果完成（默认 true）。设为 false 可立即获取当前状态',
+      required: false,
+    },
+    timeout: {
+      type: 'number',
+      description: '等待超时时间（秒），默认 150，最大 300',
+      required: false,
+    },
+  },
+  metadata: {
+    name: 'agent_output',
+    category: 'agent',
+    description: '获取后台 Agent 执行结果',
+    keywords: ['agent', 'output', 'result', 'background', '结果', '后台', '查询'],
+    deferLoading: false, // 核心工具，始终加载
+  },
+  async execute(params) {
+    const {
+      agent_id,
+      block = true,
+      timeout = 150,
+    } = params as {
+      agent_id: string;
+      block?: boolean;
+      timeout?: number;
+    };
+
+    const agentManager = getAgentManager();
+
+    // 验证超时参数
+    const effectiveTimeout = Math.min(Math.max(timeout, 1), 300);
+
+    // 获取 Agent 输出
+    const agent = await agentManager.getAgentOutput(agent_id, block, effectiveTimeout);
+
+    if (!agent) {
+      return {
+        success: false,
+        output: '',
+        error: `Agent ${agent_id} 不存在。请检查 agent_id 是否正确。`,
+      };
+    }
+
+    // 根据状态返回不同结果
+    if (agent.status === 'running') {
+      const runningTime = Math.round((Date.now() - agent.startedAt.getTime()) / 1000);
+      return {
+        success: true,
+        output: `Agent ${agent_id} 仍在运行中...\n` +
+                `- 类型: ${agent.agentName}\n` +
+                `- 任务: ${agent.description}\n` +
+                `- 已运行: ${runningTime} 秒\n\n` +
+                `稍后再次调用 agent_output 查询结果，或使用 block: true 等待完成。`,
+        metadata: {
+          agentId: agent.id,
+          status: 'running',
+          agentName: agent.agentName,
+          runningTime,
+        },
+      };
+    }
+
+    if (agent.status === 'failed') {
+      const duration = agent.completedAt
+        ? Math.round((agent.completedAt.getTime() - agent.startedAt.getTime()) / 1000)
+        : 0;
+      return {
+        success: false,
+        output: '',
+        error: `Agent ${agent_id} 执行失败:\n` +
+               `- 类型: ${agent.agentName}\n` +
+               `- 任务: ${agent.description}\n` +
+               `- 耗时: ${duration} 秒\n` +
+               `- 错误: ${agent.error || '未知错误'}`,
+        metadata: {
+          agentId: agent.id,
+          status: 'failed',
+          agentName: agent.agentName,
+          duration,
+        },
+      };
+    }
+
+    // completed
+    const duration = agent.completedAt
+      ? Math.round((agent.completedAt.getTime() - agent.startedAt.getTime()) / 1000)
+      : 0;
+
+    return {
+      success: true,
+      output: `## Agent ${agent_id} 执行完成\n\n` +
+              `- 类型: ${agent.agentName}\n` +
+              `- 任务: ${agent.description}\n` +
+              `- 耗时: ${duration} 秒\n` +
+              `- 步数: ${agent.steps || 0}\n\n` +
+              `### 结果\n\n${agent.result || '(无输出)'}`,
+      metadata: {
+        agentId: agent.id,
+        status: 'completed',
+        agentName: agent.agentName,
+        duration,
+        steps: agent.steps,
+      },
+    };
+  },
+};
diff --git a/src/tools/task/index.ts b/src/tools/task/index.ts
index 8250da0..cadf427 100644
--- a/src/tools/task/index.ts
+++ b/src/tools/task/index.ts
@@ -1 +1,2 @@
-export { taskTool, initTaskContext, updateTaskDescription } from './task.js';
+export { taskTool, initTaskContext, updateTaskDescription, getTaskContext } from './task.js';
+export { agentOutputTool } from './agent_output.js';
diff --git a/src/tools/task/task.ts b/src/tools/task/task.ts
index c46d241..d5f51e6 100644
--- a/src/tools/task/task.ts
+++ b/src/tools/task/task.ts
@@ -3,6 +3,16 @@ import type { AgentConfig } from '../../types/index.js';
 import { agentRegistry, AgentExecutor } from '../../agent/index.js';
 import { toolRegistry } from '../registry.js';
 import { SessionManager } from '../../session/index.js';
+import { getAgentManager } from '../../agent/manager.js';
+
+/**
+ * 模型预设映射
+ */
+const MODEL_PRESETS: Record<string, string> = {
+  sonnet: 'claude-sonnet-4-20250514',
+  opus: 'claude-opus-4-0-20250514',
+  haiku: 'claude-3-5-haiku-20241022',
+};
 
 // Task 工具上下文（运行时注入）
 let taskContext: {
@@ -20,6 +30,13 @@ export function initTaskContext(
   taskContext = { baseConfig, sessionManager };
 }
 
+/**
+ * 获取 Task 工具上下文
+ */
+export function getTaskContext(): typeof taskContext {
+  return taskContext;
+}
+
 /**
  * 获取 Task 工具动态描述
  */
@@ -33,20 +50,21 @@ function getTaskDescription(): string {
     .map((a) => `- ${a.name}: ${a.description}`)
     .join('\n');
 
-  return `执行子任务，委派给专门的 Agent 处理。
+  return `启动子 Agent 执行复杂任务，支持后台运行和模型选择。
 
 可用的 Agent:
 ${agentList}
 
 使用示例:
-- 使用 explore Agent 搜索代码: task({ subagent_type: "explore", prompt: "找到所有 API 路由定义" })
-- 使用 code-reviewer Agent 审查: task({ subagent_type: "code-reviewer", prompt: "审查 src/auth 目录的代码" })
-- 使用 general Agent 执行复杂任务: task({ subagent_type: "general", prompt: "分析并重构这个函数" })`;
+- 同步执行: task({ subagent_type: "explore", prompt: "找到所有 API 路由" })
+- 后台运行: task({ subagent_type: "code-reviewer", prompt: "审查代码", run_in_background: true })
+- 指定模型: task({ subagent_type: "general", prompt: "复杂分析", model: "opus" })`;
 }
 
 /**
  * Task 工具
  * 用于创建子任务，委派给指定的 Agent 处理
+ * 支持后台运行和模型选择
  */
 export const taskTool: ToolWithMetadata = {
   name: 'task',
@@ -67,19 +85,37 @@ export const taskTool: ToolWithMetadata = {
       description: '子 Agent 类型，可选: general, explore, code-reviewer',
       required: true,
     },
+    model: {
+      type: 'string',
+      description: '模型选择: sonnet, opus, haiku（默认继承主 Agent 配置）',
+      required: false,
+    },
+    run_in_background: {
+      type: 'boolean',
+      description: '是否后台运行。后台运行时立即返回 agentId，使用 agent_output 工具获取结果',
+      required: false,
+    },
   },
   metadata: {
     name: 'task',
     category: 'agent',
     description: '执行子任务，委派给专门的 Agent',
-    keywords: ['task', 'agent', 'subagent', '子任务', '委派', '探索', '审查'],
+    keywords: ['task', 'agent', 'subagent', '子任务', '委派', '探索', '审查', '后台'],
     deferLoading: false, // 核心工具，始终加载
   },
   async execute(params) {
-    const { description, prompt, subagent_type } = params as {
+    const {
+      description,
+      prompt,
+      subagent_type,
+      model,
+      run_in_background,
+    } = params as {
       description: string;
       prompt: string;
       subagent_type: string;
+      model?: string;
+      run_in_background?: boolean;
     };
 
     // 检查上下文是否已初始化
@@ -113,7 +149,52 @@ export const taskTool: ToolWithMetadata = {
       };
     }
 
-    // 2. 创建子会话
+    // 2. 处理模型选择
+    let effectiveConfig = baseConfig;
+    if (model) {
+      const modelName = MODEL_PRESETS[model];
+      if (!modelName) {
+        return {
+          success: false,
+          output: '',
+          error: `无效的模型选择: ${model}。可选: sonnet, opus, haiku`,
+        };
+      }
+      effectiveConfig = {
+        ...baseConfig,
+        model: modelName,
+      };
+    }
+
+    // 3. 后台运行模式
+    if (run_in_background) {
+      const agentManager = getAgentManager();
+      const parentSessionId = sessionManager.getSessionId() || 'standalone';
+
+      const agentId = await agentManager.runInBackground(
+        agent,
+        description,
+        prompt,
+        effectiveConfig,
+        toolRegistry,
+        {
+          parentSessionId,
+          workdir: process.cwd(),
+        }
+      );
+
+      return {
+        success: true,
+        output: `Agent ${agentId} 已在后台启动 (@${agent.name})。\n使用 agent_output 工具查询结果: agent_output({ agent_id: "${agentId}" })`,
+        metadata: {
+          agentId,
+          agent: agent.name,
+          mode: 'background',
+        },
+      };
+    }
+
+    // 4. 同步执行模式
     const parentSessionId = sessionManager.getSessionId() || 'standalone';
     const childSession = sessionManager.createChildSession(
       parentSessionId,
@@ -121,17 +202,17 @@ export const taskTool: ToolWithMetadata = {
       `${description} (@${agent.name})`
     );
 
-    // 3. 创建执行器
-    const executor = new AgentExecutor(agent, baseConfig, toolRegistry);
+    // 创建执行器
+    const executor = new AgentExecutor(agent, effectiveConfig, toolRegistry);
 
-    // 4. 执行任务
+    // 执行任务
     const result = await executor.execute(prompt, {
       parentSessionId,
       workdir: process.cwd(),
       onStream: undefined, // 子任务不使用流式输出
     });
 
-    // 5. 保存子会话
+    // 保存子会话
     childSession.messages = [
       { role: 'user', content: prompt },
       { role: 'assistant', content: result.text },
@@ -146,6 +227,7 @@ export const taskTool: ToolWithMetadata = {
           agent: agent.name,
           sessionId: childSession.id,
           steps: result.steps,
+          mode: 'sync',
         },
       };
     } else {
@@ -157,6 +239,7 @@ export const taskTool: ToolWithMetadata = {
           agent: agent.name,
           sessionId: childSession.id,
           steps: result.steps,
+          mode: 'sync',
         },
       };
     }
diff --git a/tests/unit/agent/manager.test.ts b/tests/unit/agent/manager.test.ts
new file mode 100644
index 0000000..0c97326
--- /dev/null
+++ b/tests/unit/agent/manager.test.ts
@@ -0,0 +1,255 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { AgentManager, resetAgentManager, getAgentManager } from '../../../src/agent/manager.js';
+import type { AgentInfo } from '../../../src/agent/types.js';
+import type { AgentConfig } from '../../../src/types/index.js';
+
+// Mock AgentExecutor - 使用延迟执行
+vi.mock('../../../src/agent/executor.js', () => ({
+  AgentExecutor: vi.fn().mockImplementation(() => ({
+    execute: vi.fn().mockImplementation(async () => {
+      // 延迟 200ms，让测试能在执行完成前检查状态
+      await new Promise((r) => setTimeout(r, 200));
+      return {
+        success: true,
+        text: '任务完成',
+        steps: 3,
+        sessionId: 'test-session',
+      };
+    }),
+  })),
+}));
+
+describe('AgentManager - Agent 管理器', () => {
+  let manager: AgentManager;
+  const mockAgentInfo: AgentInfo = {
+    name: 'test-agent',
+    description: '测试 Agent',
+    mode: 'subagent',
+    prompt: '你是一个测试助手',
+  };
+
+  const mockConfig: AgentConfig = {
+    provider: 'anthropic',
+    apiKey: 'test-key',
+    model: 'claude-3-5-sonnet-20241022',
+    maxTokens: 4096,
+    systemPrompt: '测试系统提示词',
+  };
+
+  const mockContext = {
+    parentSessionId: 'parent-123',
+    workdir: '/test',
+  };
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    resetAgentManager();
+    manager = new AgentManager();
+  });
+
+  describe('getAgentManager - 单例获取', () => {
+    it('返回相同的实例', () => {
+      resetAgentManager();
+      const instance1 = getAgentManager();
+      const instance2 = getAgentManager();
+      expect(instance1).toBe(instance2);
+    });
+
+    it('resetAgentManager 重置实例', () => {
+      const instance1 = getAgentManager();
+      resetAgentManager();
+      const instance2 = getAgentManager();
+      expect(instance1).not.toBe(instance2);
+    });
+  });
+
+  describe('runInBackground - 后台运行', () => {
+    it('返回 agent ID', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '测试任务',
+        '执行测试',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      expect(agentId).toBeDefined();
+      expect(typeof agentId).toBe('string');
+      expect(agentId.length).toBe(8); // 短 ID
+    });
+
+    it('创建初始状态的记录', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '测试任务',
+        '执行测试',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      const agent = manager.getAgent(agentId);
+      expect(agent).not.toBeNull();
+      expect(agent!.agentName).toBe('test-agent');
+      expect(agent!.description).toBe('测试任务');
+      expect(agent!.prompt).toBe('执行测试');
+      expect(agent!.startedAt).toBeInstanceOf(Date);
+      // 由于是异步执行，初始状态应该是 running
+      // 但由于测试环境的原因，可能已经变成其他状态
+      expect(['running', 'completed', 'failed']).toContain(agent!.status);
+    });
+  });
+
+  describe('getAgent - 获取 Agent', () => {
+    it('返回存在的 Agent', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '测试任务',
+        '执行测试',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      const agent = manager.getAgent(agentId);
+      expect(agent).not.toBeNull();
+      expect(agent!.id).toBe(agentId);
+    });
+
+    it('返回 null 当 Agent 不存在', () => {
+      const agent = manager.getAgent('non-existent');
+      expect(agent).toBeNull();
+    });
+  });
+
+  describe('getAgentOutput - 获取输出', () => {
+    it('返回 null 当 Agent 不存在', async () => {
+      const result = await manager.getAgentOutput('non-existent', false);
+      expect(result).toBeNull();
+    });
+
+    it('非阻塞模式立即返回状态', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '测试任务',
+        '执行测试',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      const result = await manager.getAgentOutput(agentId, false);
+      expect(result).not.toBeNull();
+      expect(result!.id).toBe(agentId);
+    });
+
+    it('阻塞模式等待完成', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '测试任务',
+        '执行测试',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      // 使用阻塞模式等待
+      const result = await manager.getAgentOutput(agentId, true, 5);
+      expect(result).not.toBeNull();
+      // 等待后应该是完成状态
+      expect(['completed', 'failed']).toContain(result!.status);
+    });
+  });
+
+  describe('listAgents - 列出所有 Agent', () => {
+    it('返回所有 Agent', async () => {
+      await manager.runInBackground(
+        mockAgentInfo,
+        '任务1',
+        '执行1',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+      await manager.runInBackground(
+        mockAgentInfo,
+        '任务2',
+        '执行2',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      const agents = manager.listAgents();
+      expect(agents.length).toBe(2);
+    });
+
+    it('空管理器返回空数组', () => {
+      const agents = manager.listAgents();
+      expect(agents).toEqual([]);
+    });
+  });
+
+  describe('listRunningAgents - 列出运行中的 Agent', () => {
+    it('返回数组', async () => {
+      await manager.runInBackground(
+        mockAgentInfo,
+        '任务1',
+        '执行1',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      const running = manager.listRunningAgents();
+      expect(Array.isArray(running)).toBe(true);
+    });
+  });
+
+  describe('cleanup - 清理', () => {
+    it('清理已完成的 Agent', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '任务',
+        '执行',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      // 等待一段时间让 Agent 完成（无论成功或失败）
+      await new Promise((r) => setTimeout(r, 100));
+
+      // 确认 Agent 不再是 running 状态
+      const beforeCleanup = manager.getAgent(agentId);
+      expect(beforeCleanup).not.toBeNull();
+      expect(['completed', 'failed']).toContain(beforeCleanup?.status);
+
+      // 设置 maxAge 为 0，立即清理
+      manager.cleanup(0);
+
+      const agent = manager.getAgent(agentId);
+      expect(agent).toBeNull();
+    });
+
+    it('不清理运行中的 Agent', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '任务',
+        '执行',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      // 立即清理（不等待）
+      manager.cleanup(0);
+
+      // cleanup 应该不会报错
+      // Agent 可能还在运行（取决于执行速度）
+      // 这里只验证 cleanup 不会崩溃
+      expect(true).toBe(true);
+    });
+  });
+});
diff --git a/tests/unit/tools/task/agent_output.test.ts b/tests/unit/tools/task/agent_output.test.ts
new file mode 100644
index 0000000..02aa251
--- /dev/null
+++ b/tests/unit/tools/task/agent_output.test.ts
@@ -0,0 +1,160 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { agentOutputTool } from '../../../../src/tools/task/agent_output.js';
+import { getAgentManager, resetAgentManager } from '../../../../src/agent/manager.js';
+
+// Mock AgentExecutor - 使用延迟执行让测试更可控
+vi.mock('../../../../src/agent/executor.js', () => ({
+  AgentExecutor: vi.fn().mockImplementation(() => ({
+    execute: vi.fn().mockImplementation(async () => {
+      await new Promise((r) => setTimeout(r, 50));
+      return {
+        success: true,
+        text: '任务完成结果',
+        steps: 3,
+        sessionId: 'test-session',
+      };
+    }),
+  })),
+}));
+
+describe('agentOutputTool - Agent 输出工具', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    resetAgentManager();
+  });
+
+  describe('工具定义', () => {
+    it('有正确的名称', () => {
+      expect(agentOutputTool.name).toBe('agent_output');
+    });
+
+    it('有正确的元数据', () => {
+      expect(agentOutputTool.metadata.category).toBe('agent');
+      expect(agentOutputTool.metadata.keywords).toContain('agent');
+      expect(agentOutputTool.metadata.keywords).toContain('output');
+      expect(agentOutputTool.metadata.keywords).toContain('background');
+    });
+
+    it('agent_id 参数是必须的', () => {
+      expect(agentOutputTool.parameters.agent_id.required).toBe(true);
+    });
+
+    it('block 和 timeout 参数是可选的', () => {
+      expect(agentOutputTool.parameters.block.required).toBe(false);
+      expect(agentOutputTool.parameters.timeout.required).toBe(false);
+    });
+  });
+
+  describe('execute - 执行', () => {
+    it('Agent 不存在时返回错误', async () => {
+      const result = await agentOutputTool.execute({
+        agent_id: 'non-existent-id',
+      });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('不存在');
+    });
+
+    it('返回 Agent 的状态', async () => {
+      const manager = getAgentManager();
+      const agentId = await manager.runInBackground(
+        {
+          name: 'test-agent',
+          description: '测试',
+          mode: 'subagent',
+        },
+        '测试任务',
+        '执行测试',
+        {
+          provider: 'anthropic',
+          apiKey: 'test',
+          model: 'test',
+          maxTokens: 1000,
+          systemPrompt: 'test',
+        },
+        {} as any,
+        { parentSessionId: 'parent', workdir: '/test' }
+      );
+
+      // 立即查询（不阻塞）
+      const result = await agentOutputTool.execute({
+        agent_id: agentId,
+        block: false,
+      });
+
+      // 应该成功返回状态（可能是 running 或 completed）
+      expect(result.output).toBeDefined();
+      expect(result.metadata?.agentId).toBe(agentId);
+    });
+
+    it('阻塞等待后返回结果', async () => {
+      const manager = getAgentManager();
+      const agentId = await manager.runInBackground(
+        {
+          name: 'test-agent',
+          description: '测试',
+          mode: 'subagent',
+        },
+        '测试任务',
+        '执行测试',
+        {
+          provider: 'anthropic',
+          apiKey: 'test',
+          model: 'test',
+          maxTokens: 1000,
+          systemPrompt: 'test',
+        },
+        {} as any,
+        { parentSessionId: 'parent', workdir: '/test' }
+      );
+
+      // 使用阻塞模式等待
+      const result = await agentOutputTool.execute({
+        agent_id: agentId,
+        block: true,
+        timeout: 5,
+      });
+
+      // 等待后应该有确定的状态
+      expect(result.metadata?.status).toBeDefined();
+      expect(['running', 'completed', 'failed']).toContain(result.metadata?.status);
+    });
+
+    it('返回包含正确字段的输出', async () => {
+      const manager = getAgentManager();
+      const agentId = await manager.runInBackground(
+        {
+          name: 'test-agent',
+          description: '测试',
+          mode: 'subagent',
+        },
+        '测试任务',
+        '执行测试',
+        {
+          provider: 'anthropic',
+          apiKey: 'test',
+          model: 'test',
+          maxTokens: 1000,
+          systemPrompt: 'test',
+        },
+        {} as any,
+        { parentSessionId: 'parent', workdir: '/test' }
+      );
+
+      // 等待完成
+      await new Promise((r) => setTimeout(r, 200));
+
+      const result = await agentOutputTool.execute({
+        agent_id: agentId,
+        block: false,
+      });
+
+      // 检查返回了有效结果
+      expect(result.output).toBeDefined();
+      expect(result.metadata?.agentId).toBe(agentId);
+      expect(result.metadata?.agentName).toBe('test-agent');
+      // 状态应该是完成或失败（由于 mock，可能会失败）
+      expect(['completed', 'failed']).toContain(result.metadata?.status);
+    });
+  });
+});