Worked on the modelcontextprotocol/go-sdk repository to enhance backend error handling in Go, focusing on transport-layer reliability. Addressed a bug in the Write function by ensuring transport errors are preserved within the error chain, allowing downstream callers to inspect transport-level issues using errors.As. This approach maintained consistency with existing OAuth handler error-wrapping practices, utilizing Go’s %w formatting for error propagation. The update improved observability and diagnostics for client authentication and transport failures, ultimately reducing mean time to resolution for related issues. The work demonstrated attention to robust error handling and backend development principles, with a targeted, maintainable code change.