D

VAPI•6mo ago

dead-brown

Streamable-MCP server (n8n) fails in Test Tool — “protocol not supported” & Google Calendar act

Hi Vapi team!

Setup

• Self-hosted n8n (latest)
  
  • A flow that starts with MCP Server Trigger ➜ branches to Google Calendar nodes (create / get / update / delete).
• MCP endpoint: https://<my-domain>/mcp/…https://<my-domain>/mcp/…
• In Vapi Dashboard → Tools I created an MCP Tool with that URL and attached it to my assistant.

What happens

1. When I click Test in the Tool editor I immediately get the warning
   Streamable HTTP protocol is not supported in testing yetStreamable HTTP protocol is not supported in testing yet.
2. 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?