307 Temporary Redirect

[2495710777]

INFO: 127.0.0.1:56991 - "POST /mcp HTTP/1.1" 307 Temporary Redirect
INFO: 127.0.0.1:56991 - "POST /mcp/ HTTP/1.1" 200 OK

After using
mcp.run(transport="streamable-http")
to start the server, why does the client always redirect to '/mcp/' when requesting the server?

[ch-xhr]

same issue.

[zhouguangming]

same

[nightzjp]

http://localhost/mcp => http://localhost/mcp/

[chi2liu]

set your streamable_http_path='/mcp/'

[chi2liu]

#781

[jbovet]

hey, it took me a while to figure this out, I even raised an issue!

thanks everyone for your help!

[tobegit3hub]

It is the issue of fastapi. May close in this project.

[pamelafox]

Just to share code, the following results in those errors:

streamablehttp_client("http://myserver.com/mcp")

whereas this resolves them:

streamablehttp_client("http://myserver.com/mcp/")

It appears that the streamable_http_client cannot handle the redirect, and when we use Starlette/FastAPI, /mcp gets turned into /mcp/, so we need to give the direct route of /mcp.

Perhaps streamable_http_client could add redirect handling? But not all clients will handle it (see VS Code issue).