Building a Custom MCP Server

# server.py
from mcp.server import Server
from mcp.server.stdio import stdio_server
from mcp.types import Tool, TextContent

app = Server("my-server")

@app.list_tools()
async def list_tools():
    return [
        Tool(
            name="get_weather",
            description="Get current weather for a city",
            inputSchema={
                "type": "object",
                "properties": {
                    "city": {"type": "string", "description": "City name"}
                },
                "required": ["city"]
            }
        )
    ]

@app.call_tool()
async def call_tool(name: str, arguments: dict):
    if name == "get_weather":
        city = arguments["city"]
        # Your actual logic here
        weather = fetch_weather(city)
        return [TextContent(type="text", text=f"Weather in {city}: {weather}")]

if __name__ == "__main__":
    import asyncio
    asyncio.run(stdio_server(app))