模型上下文协议（MCP）

from mcp.server.fastmcp import FastMCP

mcp = FastMCP("Math")

@mcp.tool()
def add(a: int, b: int) -> int:
    """加两个数字"""
    return a + b

@mcp.tool()
def multiply(a: int, b: int) -> int:
    """乘两个数字"""
    return a * b

if __name__ == "__main__":
    mcp.run(transport="stdio")

from mcp.server.fastmcp import FastMCP

mcp = FastMCP("Weather")

@mcp.tool()
async def get_weather(location: str) -> str:
    """获取指定地点的天气。"""
    return "纽约总是阳光明媚"

if __name__ == "__main__":
    mcp.run(transport="streamable-http")

from langchain_core.tools import tool
from langchain_mcp_adapters.tools import to_fastmcp
from mcp.server.fastmcp import FastMCP


@tool
def add(a: int, b: int) -> int:
    """加两个数字"""
    return a + b

@tool
def get_user_info(user_id: str) -> str:
    """获取用户信息"""
    return f"用户 {user_id} 处于活跃状态"


# 将 LangChain 工具转换为 FastMCP 格式
fastmcp_tools = [to_fastmcp(tool) for tool in (add, get_user_info)]

# 使用转换后的工具创建服务器
mcp = FastMCP("LangChain 工具", tools=fastmcp_tools)
mcp.run(transport="stdio")

from langchain_mcp_adapters.tools import load_mcp_tools

client = MultiServerMCPClient({...})
async with client.session("math") as session:
    tools = await load_mcp_tools(session)