The refute_match on response.location already proves create_forward_auth_token did nothing: the cache.write and the URL rewrite are back-to-back with no branch between them, so the URL lacking fa_token= implies no cache entry was written. The instance_variable_get(:@data) inspection was both redundant and coupled to MemoryStore's private layout. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>