AI-agent/04_mcp_homework/step2_call_tool.py

"""
第 2 步测试：连接本地 MCP Server，并直接调用 MCP 工具。

这一步还不接大模型，只验证：
1. MCP Client 能发现工具
2. MCP Client 能调用工具
3. MCP Server 能返回结果

运行：
python step2_call_tool.py
"""

from __future__ import annotations

import asyncio
import sys
from pathlib import Path

from langchain_mcp_adapters.client import MultiServerMCPClient


async def main() -> None:
    server_file = Path(__file__).with_name("my_mcp_demo.py").resolve()

    client = MultiServerMCPClient(
        {
            "travel-tools": {
                "transport": "stdio",
                "command": sys.executable,
                "args": [str(server_file)],
            }
        }
    )

    tools = await client.get_tools()
    hotel_tool = next(tool for tool in tools if tool.name == "search_hotels")
    # 调用这个mcp工具
    result = await hotel_tool.ainvoke(
        {
            "city": "重庆",
            "nights": 2,
            "budget_per_night": 400,
        }
    )

    print("MCP 工具调用结果：")
    print(result)


if __name__ == "__main__":
    asyncio.run(main())