MCP Python SDK

# Server (stdio transport — for Claude Desktop, local agents)
from mcp.server.fastmcp import FastMCP

mcp = FastMCP('My Server')

@mcp.tool()
def add(a: int, b: int) -> int:
    """Add two numbers"""
    return a + b

@mcp.resource('data://{name}')
def get_data(name: str) -> str:
    """Fetch named data"""
    return f'Data for {name}'

@mcp.prompt()
def review_code(code: str) -> str:
    return f'Please review this code:\n\n{code}'

if __name__ == '__main__':
    mcp.run()  # defaults to stdio

# ---

# Server (streamable-http — for remote/production deployments)
mcp = FastMCP('My Server', stateless_http=True, json_response=True)

if __name__ == '__main__':
    mcp.run(transport='streamable-http')  # serves at /mcp by default

# ---

# Client (connecting to an MCP server)
from mcp import ClientSession
from mcp.client.streamable_http import streamablehttp_client
import asyncio

async def main():
    async with streamablehttp_client('http://localhost:8000/mcp') as (r, w, _):
        async with ClientSession(r, w) as session:
            await session.initialize()
            tools = await session.list_tools()
            result = await session.call_tool('add', {'a': 1, 'b': 2})
            print(result)

asyncio.run(main())