FastMCP

What it does

A Python framework for building MCP servers, clients and interactive apps. You write ordinary Python functions and FastMCP generates the tool schemas, validation and docs. FastMCP 1.0 was folded into the official MCP Python SDK in 2024; this is the actively maintained standalone project. Apache-2.0.

Who it's for

Python developers who want to turn their own functions or APIs into an MCP server quickly.

How to set it up

1. Add it to your project with uv:

   bashCopy

   uv add fastmcp

2. Create server.py:

   textCopy

   from fastmcp import FastMCP
   
   mcp = FastMCP("Demo")
   
   @mcp.tool
   def add(a: int, b: int) -> int:
       """Add two numbers"""
       return a + b
   
   if __name__ == "__main__":
       mcp.run()

3. Run it with python server.py, then add it to your MCP client. A TypeScript counterpart is available as @prefecthq/fastmcp-ts.

Check the official FastMCP docs for the latest steps.

Example prompts

Turn the functions in utils/weather.py into a FastMCP server with one tool each.

Add a FastMCP resource that exposes our README as context.

Write a FastMCP client script that connects to my server and lists its tools.

Demo