Supabase MCP OAuth fails with {"message":"Unrecognized client_id"} in Cursor / Claude Code
The most common root cause is a stale cached OAuth Dynamic Client Registration on the client side: the client keeps re-sending a client_id that Supabase's auth server no longer recognizes, so every login attempt fails the same way. Fix: delete the cached registration, then authenticate again so the client performs a f…
Problem outcome: unknown