Add method for retrieving current starlette request to FastMCP context

[jlowin]

Easily access the current starlette request from context, as described in modelcontextprotocol/python-sdk#380

NOTE: renamed get_http_request in #303

Server:

from fastmcp import Context, FastMCP

mcp = FastMCP()


@mcp.tool()
async def add_and_headers(a: int, b: int, ctx: Context) -> dict[str, Any]:
    request = ctx.get_starlette_request()
    return dict(result=a + b, headers=request.headers)


if __name__ == "__main__":
    mcp.run(transport="sse")

Client:

import asyncio
from fastmcp import Client


async def main():
    async with Client("http://localhost:8000/sse") as client:
        result = await client.call_tool("add_and_headers", dict(a=1, b=2))
        print(result)


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

[Copilot]

Pull Request Overview

This PR adds functionality to retrieve the current Starlette request from the FastMCP context. The key changes include:

• Introducing a context manager and a ContextVar to store the Starlette request.
• Wrapping the SSE Starlette app with a new RequestMiddleware.
• Adding the get_starlette_request method in the Context class for retrieving the active Starlette request.

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
src/fastmcp/utilities/http.py	New context manager and middleware to track the active Starlette request.
src/fastmcp/server/server.py	Wraps the SSE app with RequestMiddleware to support request tracking.
src/fastmcp/server/context.py	Adds get_starlette_request to the Context class and updates Pydantic model configuration.

Files not reviewed (1)

• docs/servers/context.mdx: Language not supported

Comments suppressed due to low confidence (2)

src/fastmcp/server/context.py:230

• [nitpick] The Context method 'get_starlette_request' delegates to a global function 'get_current_starlette_request'; consider renaming the global function to '_get_current_starlette_request' to clarify its internal use.

def get_starlette_request(self) -> Request:

src/fastmcp/utilities/http.py:42

• [nitpick] Consider verifying that the 'scope' contains the expected HTTP keys before instantiating a Request in RequestMiddleware to prevent potential runtime errors when handling non-HTTP requests.

async def __call__(self, scope, receive, send):