Anar Azadaliyev developed robust OAuth client authentication handling for the modelcontextprotocol/rust-sdk repository, focusing on improving provider compatibility and reducing configuration errors. He introduced support for multiple OAuth token endpoint authentication methods by adding a configurable field to OAuthClientConfig and refactored the logic to dynamically derive the method from server metadata. This approach enabled seamless integration with providers like HubSpot and minimized manual setup, addressing common TokenExchangeFailed errors. Anar expanded test coverage to ensure correct behavior across supported methods, aligned with RFC 6749, and maintained high code quality through consistent formatting and detailed commit documentation using Rust and API integration skills.