MCP Patterns

from mcp.server import Server
from mcp.server.stdio import stdio_server

app = Server("my-server")

@app.list_tools()
async def list_tools():
    return [
        {
            "name": "my_tool",
            "description": "Does something useful",
            "inputSchema": {
                "type": "object",
                "properties": {
                    "query": {"type": "string", "description": "Search query"}
                },
                "required": ["query"]
            }
        }
    ]

@app.call_tool()
async def call_tool(name: str, arguments: dict):
    if name == "my_tool":
        result = await do_something(arguments["query"])
        return {"content": [{"type": "text", "text": result}]}
    raise ValueError(f"Unknown tool: {name}")

async def main():
    async with stdio_server() as (read_stream, write_stream):
        await app.run(read_stream, write_stream, app.create_initialization_options())

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

my-mcp-server/
├── src/
│   └── my_server/
│       ├── __init__.py
│       ├── server.py       # Main server logic
│       ├── tools.py        # Tool handlers
│       └── resources.py    # Resource handlers
├── pyproject.toml
└── README.md

{
  "mcpServers": {
    "my-server": {
      "command": "python",
      "args": ["-m", "my_server"],
      "env": {
        "MY_API_KEY": "your-key-here"
      }
    }
  }
}

{
  "mcpServers": {
    "my-server": {
      "command": "uv",
      "args": ["run", "--directory", "/path/to/my-server", "python", "-m", "my_server"],
      "env": {
        "MY_API_KEY": "your-key-here"
      }
    }
  }
}