FastAPI mount FastMCP didn't use /mcp path

[MarshallEriksen-shaomingyang]

I use FastAPI.mount(path="/mcp", app=FastMCP.sse_app()) and It works but client request wrong path

[jlowin]

I believe this is a known issue with the SSE app, see e.g. modelcontextprotocol/python-sdk#386 and modelcontextprotocol/python-sdk#540 which both attempt to fix it. It will need to be fixed in the low-level SDK if that's the case.