correct-apricot•3mo ago
Streamable-MCP server (n8n) fails in Test Tool — “protocol not supported” & Google Calendar act
Hi Vapi team! 👋
I have a Self-hosted n8n (1.93.0)
A flow that starts with MCP Server Trigger ➜ branches to Google Calendar nodes (create / get / update / delete).
MCP endpoint: https://<my-domain>/mcp/…
In Vapi Dashboard → Tools I created an MCP Tool with that URL and attached it to my assistant.
What happens
When I click Test in the Tool editor I immediately get the warning
"Streamable HTTP protocol is not supported in testing yet."
During a real assistant test call the agent says it can’t read my Google Calendar; the logs show the tool list was never fetched.
How can I fix this?
1 Reply
VAPI's testing interface only supports SSE (Server-Sent Events) protocol, but your setup is defaulting to Streamable HTTP. For the test call, could you please send a call id?