Worked on stabilizing the authentication flow in the modelcontextprotocol/csharp-sdk repository by addressing a runtime crash related to null ResourceMetadata during event-driven scenarios. The solution involved updating the authentication handler to prioritize event-provided ResourceMetadata when Options.ResourceMetadata was unavailable, enhancing system resilience for clients relying on dynamic metadata. Exception messages were revised to clarify the new logic, and comprehensive unit tests were added to cover these dynamic cases and prevent regressions. This work leveraged C# for backend development, with a focus on API development, authentication, and robust unit testing to improve reliability in event-driven authentication workflows for downstream services.