separate_server_example.py

from fastapi import FastAPI
import asyncio
import uvicorn

from examples.shared.apps import items
from examples.shared.setup import setup_logging

from fastapi_mcp import FastApiMCP

setup_logging()


MCP_SERVER_HOST = "localhost"
MCP_SERVER_PORT = 8000
ITEMS_API_HOST = "localhost"
ITEMS_API_PORT = 8001


# Take the FastAPI app only as a source for MCP server generation
mcp = FastApiMCP(
    items.app,
    base_url=f"http://{ITEMS_API_HOST}:{ITEMS_API_PORT}",  # Note how the base URL is the **Items API** URL, not the MCP server URL
)

# And then mount the MCP server to a separate FastAPI app
mcp_app = FastAPI()
mcp.mount(mcp_app)


def run_items_app():
    uvicorn.run(items.app, port=ITEMS_API_PORT)


def run_mcp_app():
    uvicorn.run(mcp_app, port=MCP_SERVER_PORT)


# The MCP server depends on the Items API to be available, so we need to run both.
async def main():
    await asyncio.gather(asyncio.to_thread(run_items_app), asyncio.to_thread(run_mcp_app))


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