MCP Server Example in Python: Build Your First Model Context Protocol Server in 30 Minutes

You want to expose your own data or tools to Claude and other AI assistants. A Python MCP server is the cleanest way.

## MCP Server Example in Python: Build Your First Model Context Protocol Server in 30 Minutes Building an MCP server in Python in 2026 is a solved problem: the official SDK (mcp) handles the protocol, and you just write plain functions. This tutorial builds a working server that exposes a tool, then connects it to Claude Desktop. ## Step 1: Install ```bash pip install "mcp[cli]" ``` ## Step 2: The Server (about 20 lines) ```python from mcp.server.fastmcp import FastMCP mcp = FastMCP("Weather Demo") @mcp.tool() def get_weather(city: str) -> str: # In production, call a real weather API here return "Weather in " + city + ": 22C, partly cloudy" if __name__ == "__main__": mcp.run() ``` That is a complete server. One decorator, one run call. ## Step 3: Test It ```bash python server.py # in another terminal: mcp dev server.py ``` The mcp dev command opens an inspector UI where you can call get_weather and see the result. ## Step 4: Connect to Claude Desktop Add to claude_desktop_config.json: ```json { "mcpServers": { "weather": { "command": "python", "args": ["C:/path/to/server.py"] } } } ``` Restart Claude Desktop. Claude can now call get_weather("Tokyo") and use the result in conversation. ## What the FastMCP Layer Does For You | Concern | Handled by | |---------|-----------| | JSON-RPC transport | SDK (stdio or SSE/HTTP) | | Tool discovery | SDK introspection | | Input validation | Pydantic models | | Error handling | SDK error codes | ## FAQ **FastMCP or raw SDK?** FastMCP for new projects - it is the official high-level API and cuts boilerplate by 80%. **Can I expose a REST API as MCP?** Yes, wrap the REST calls inside a @mcp.tool() function; the LLM then calls your tool, which calls the API. **Is there a TypeScript version?** Yes, the official SDK is first-class in TypeScript too. Python and TS cover the vast majority of servers.