MCP OAuth login now delays client registration when the server's discovery info already offers it
When Claude Code connects to an MCP (Model Context Protocol) server that uses OAuth login, it now checks the server's discovery metadata for a registration_endpoint or support for client_id_metadata_document_supported. If either is present, a new registrationOfferedByDiscovery flag is set, and if there's no access or refresh token yet, Claude Code defers registering itself as a client until the actual authentication step instead of trying to register right away.
Previously, missing client info could fail immediately; now, if the server's discovery data already offers a way to register, Claude Code waits and lets registration happen at authentication time instead of failing early.