FastMCP

FastMCP

FastMCP is a high-level Python framework for building Model Context Protocol (MCP) servers with minimal boilerplate. Inspired by FastAPI's decorator pattern, it lets you expose Python functions as MCP tools, resources, and prompts in seconds — handling all protocol-level serialization, schema generation, and transport setup automatically.

Key features

• Decorator-based API: @mcp.tool(), @mcp.resource(), @mcp.prompt() — just annotate functions
• Automatic JSON Schema generation from Python type hints
• Supports stdio and SSE (HTTP) transports
• Built-in testing utilities — run MCP servers in-process for unit tests
• Async-first but sync functions work too
• Apache-2.0 license

Quick start

pip install fastmcp

from fastmcp import FastMCP

mcp = FastMCP("My AI Tool Server")

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

@mcp.resource("config://settings")
def get_settings() -> str:
    """Return application settings."""
    return "debug=false, version=1.0"

if __name__ == "__main__":
    mcp.run()  # stdio transport by default

# Run with SSE transport for HTTP access
fastmcp run server.py --transport sse --port 8000

Install via ai-supply

npx ai-supply add fastmcp-python

Curated mirror of the open-source FastMCP (Apache-2.0). Get it from the source.