In April 2025, develop@closetheworld.net enhanced the modelcontextprotocol/csharp-sdk repository by implementing custom headers support for the SSE client. This work focused on extending SseClientSessionTransport and the ReceiveMessageAsync method to allow authentication tokens and metadata to be sent with SSE requests, improving integration with downstream services and strengthening security through header-based authentication. Using C# and .NET asynchronous programming, the developer addressed HTTP header handling within the SSE transport layer. The feature reduced the need for workaround code and increased the SDK’s readiness for secure integrations, demonstrating solid skills in API integration and backend development over the course of the month.