MCP Server 实战

{
  "mcpServers": {
    "postgres": {
      "command": "npx",
      "args": [
        "-y",
        "@anthropic/mcp-server-postgres",
        "postgresql://user:password@localhost:5432/mydb"
      ]
    }
  }
}

{
  "mcpServers": {
    "postgres": {
      "command": "npx",
      "args": [
        "-y",
        "@anthropic/mcp-server-postgres",
        "${DATABASE_URL}"
      ],
      "env": {
        "DATABASE_URL": "${DATABASE_URL}"
      }
    }
  }
}

你: 帮我查看 users 表的结构和前 5 条记录

Claude Code: 我来查询数据库...
[调用 MCP 工具: query]
SQL: SELECT column_name, data_type FROM information_schema.columns WHERE table_name = 'users';

users 表结构：
- id: integer (主键)
- email: varchar
- name: varchar
- created_at: timestamp

[调用 MCP 工具: query]
SQL: SELECT * FROM users LIMIT 5;

前 5 条记录：
| id | email              | name   | created_at          |
|----|--------------------|--------|---------------------|
| 1  | alice@example.com  | Alice  | 2026-01-15 10:30:00 |
| 2  | bob@example.com    | Bob    | 2026-01-16 14:20:00 |
...

{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": ["-y", "@anthropic/mcp-server-github"],
      "env": {
        "GITHUB_TOKEN": "${GITHUB_TOKEN}"
      }
    }
  }
}

你: 帮我创建一个 Issue，标题是 "修复登录页面样式问题"，描述登录按钮在移动端不居中

Claude Code: 我来通过 GitHub API 创建 Issue...
[调用 MCP 工具: create_issue]
已成功创建 Issue #42: "修复登录页面样式问题"
链接: https://github.com/user/repo/issues/42

{
  "mcpServers": {
    "brave-search": {
      "command": "npx",
      "args": ["-y", "@anthropic/mcp-server-brave-search"],
      "env": {
        "BRAVE_API_KEY": "${BRAVE_API_KEY}"
      }
    }
  }
}

{
  "mcpServers": {
    "project-db": {
      "command": "npx",
      "args": ["-y", "@anthropic/mcp-server-postgres", "${DATABASE_URL}"]
    }
  }
}

{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": ["-y", "@anthropic/mcp-server-github"],
      "env": {
        "GITHUB_TOKEN": "${GITHUB_TOKEN}"
      }
    }
  }
}

全局配置: github (默认 Token)
项目配置: github (项目专属 Token)
→ 最终使用: 项目配置的 github Server

MCP Servers:
  filesystem  ✓ running  (stdio)   3 tools
  postgres    ✗ error    (stdio)   connection refused
  github      ✓ running  (stdio)   8 tools

错误: connection refused

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "Node16",
    "moduleResolution": "Node16",
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true
  },
  "include": ["src/**/*"]
}

{
  "mcpServers": {
    "weather": {
      "command": "node",
      "args": ["/path/to/mcp-server-weather/dist/index.js"]
    }
  }
}

// 添加天气预报工具
server.tool(
  "get_forecast",
  "获取指定城市未来几天的天气预报",
  {
    city: z.string().describe("城市名称"),
    days: z.number().min(1).max(7).describe("预报天数，1-7"),
  },
  async ({ city, days }) => {
    const forecast = await fetchForecast(city, days);
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(forecast, null, 2),
        },
      ],
    };
  }
);

// 添加资源：天气 API 使用说明
server.resource(
  "weather-api-docs",
  "weather://docs",
  async (uri) => {
    return {
      contents: [
        {
          uri: uri.href,
          mimeType: "text/plain",
          text: "天气 Server 使用说明：支持 get_weather 和 get_forecast 两个工具...",
        },
      ],
    };
  }
);

1. 启动（Start）
   └─ Claude Code 读取配置 → 启动 Server 进程

2. 初始化（Initialize）
   └─ Client 与 Server 握手 → 交换能力信息

3. 就绪（Ready）
   └─ Server 注册工具和资源 → Client 获取可用工具列表

4. 运行（Running）
   └─ 响应工具调用请求 → 返回结果

5. 关闭（Shutdown）
   └─ Claude Code 退出 → Server 进程终止

// 在自定义 Server 中处理关闭
process.on("SIGINT", async () => {
  // 关闭数据库连接
  await db.close();
  // 清理临时文件
  await cleanup();
  process.exit(0);
});

错误: Permission denied