high85%
Claude Code MCP login fails with Unrecognized client_id due to version-keyed OAuth token storage and stale client registration
Supabase MCP plugin stores OAuth tokens in a local keychain keyed by a hash of the MCP config that includes the X-Source-Version header. Upgrading from 0.1.12 to 0.1.13 created a second empty credential slot. The new slot contains a client registration that Supabase no longer recognizes, returning HTTP 422 Unrecognized client_id. Claude Code reuses this dead registration instead of re-registering, so login always fails before consent.