Access FastAPI Context through MCP server

[tanmaygar]

I currently have a FastAPI app that has its own lifespan. I am creating an mcp server and mounting it on top of this fastapi app. I am trying to find a way to access the Context of this FastAPI app through my MCP server. Can someone please guide me if it is possible?

app = FastAPI(lifespan=lifespan_func)
mcp = FastMCP()
mcp_app = mcp.http_app(path="/sse", transport="sse")
app.mount("/mcp_server", mcp_app)

I then run the app using uvicorn

I am using a Langgraph agent to access this mcp server using

sse_client(**server_params) as (read, write)

where server_params contains the url and a list of some default headers that is being used by some of the mcp tools.

Now I want to access app context into mcp_app context. Is there a way to do this?

[itsomar278]

Hi , did you figure this out ?

There was multiple solutions like modifying the state of the graph and adding new things needed as tool parms .

Another thing was a middlware on the mcp server and if you are using the Langchain MCP client you can inject whatever you need into the headers of the request and re use it later in your tools .

Still I'm thinking there should be a direct way to not lose the Parent App context without the unnecessary complexity of modifying the graph state .

I'll appreciate if you share your findings on this