catalog was the only domain that split its MCP route in two: the main
route on POST/DELETE, and a separate -stream route matching GET, whose
only purpose was to carry a request-termination plugin answering 405
"SSE stream is not offered on this endpoint". The other four domains
keep one route with GET, POST and DELETE.
That opt-out is not a fix the other four missed — it gives up a feature
the plugin implements. ai-mcp-proxy handles non-POST itself: its handler
carries an explicit non-POST branch, MCP session handling, an SSE
subscription waiting on notifications/tools/list_changed, and Accept
header validation for application/json and text/event-stream. GET is the
server-to-client channel of MCP Streamable HTTP, and on the other four
domains it reaches the plugin and works.
Nothing in git or in any comment records why catalog gave it up, and the
plugin and binding behind it were applied by hand three days after the
route landed — they were never in git at all. So on a cluster rebuilt
from git the split had no guard behind it: GET fell through to a route
with no plugin whose service points back at the gateway itself.
Drop the stream route and put GET back on the MCP route, so the five
domains are identical again.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Stéphane Tailland