Tool Naming

FastAPI-MCP uses the operation_id from your FastAPI routes as the MCP tool names. When you don’t specify an operation_id, FastAPI auto-generates one, but these can be cryptic. Compare these two endpoint definitions:

# Auto-generated operation_id (something like "read_user_users__user_id__get")
@app.get("/users/{user_id}")
async def read_user(user_id: int):
    return {"user_id": user_id}

# Explicit operation_id (tool will be named "get_user_info")
@app.get("/users/{user_id}", operation_id="get_user_info")
async def read_user(user_id: int):
    return {"user_id": user_id}

For clearer, more intuitive tool names, we recommend adding explicit operation_id parameters to your FastAPI route definitions. To find out more, read FastAPI’s official docs about advanced config of path operations.

Getting Started

Configurations

Advanced Usage