5.3.15
A connector could not sign in, and the reason was a 404.
Both OAuth RFCs build the discovery URL by putting the well-known segment in
front of the resource's own path rather than at the site root, and every current
connector asks that way:
/.well-known/oauth-protected-resource/wp-json/mcp/niranzwp
Only the bare path was answered. So the whole browser grant was there — the
authorize endpoint, PKCE, the approval screen, the token exchange — and no
connector could reach any of it, because the first document it looks for was
missing.
Both forms are answered now. A suffix that is not this site's own MCP endpoint
still is not: claiming to be the authorization server for some other path would
be answering a question nobody asked.
The WWW-Authenticate header on the MCP endpoint points at the path-inserted
URL as well, which is the canonical one for this resource.