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Vapi AI

As title describes, VAPI used to call GET request to sse endpoints (like it should be doing) but since yesterday 6 pm - ish, it started calling POST, causing error on the MCP tool connection.

We are seeing the same thing, first occurence for us: 11:57 UTC

For anyone who's encoutering issue, use streamable-http instead of sse. This will fix for now.

streamable-http does not solve the issue for us since Vapi still initiates the connection with a GET request which streamable-http does not accept

Seems like GET for http/mcp works on our side 🤔

What backend are you using? We're on python `fast-agent-mcp~=0.2.26`

Perhaps there's a mismatch between the protocols

Working streamable-http log (not vapi)
```
INFO:     127.0.0.1:56020 - "POST /mcp/ HTTP/1.1" 200 OK
INFO:     127.0.0.1:56022 - "POST /mcp/ HTTP/1.1" 202 Accepted
INFO:     127.0.0.1:56026 - "GET /mcp/ HTTP/1.1" 200 OK
INFO:     127.0.0.1:56042 - "POST /mcp/ HTTP/1.1" 200 OK
INFO:     127.0.0.1:56046 - "POST /mcp/ HTTP/1.1" 200 OK
```

Failing streamable-http log (vapi):
```
INFO: 169.254.169.126:47754 - "GET /mcp/ HTTP/1.1" 400 Bad Request
```

we are using fastmcp = 2.7.1 instead of fast-agent-mcp. Not too sure about that one

any word on this? we're having the same issue. just started happening yesterday with an mcp server that was previously working. the mcp testing tool in the vapi dashboard is still able to call tools on the mcp server but the assistant makes a POST to /sse and gets a "method not allowed" error

Problem appears to be resolved, SSE server is working for us.
I lied earlier, we are using the "official" `mcp~=1.9.1` package

As SSE will be deprecated at some point, please vote this feature so we can get at least a more robust and stable SHTTP MCP client. 
https://vapi.canny.io/bug-reports/p/http-streamable-transport-for-mcp-connections-not-working

if still persist try using streamable http

Hi all, we merged an update to production last night directly addressing the MCP tool. Please confirm if it is working as expected.

Vapi still uses POST for /sse. Do we migrate to Http streamable for external mcp servers?

We maintain POST /sse for existing integrations, but yes we recommend migrating to HTTP streamable.