Elliot Chapman developed robust HTTP header support for MCP tooling in the dotnet/extensions repository, focusing on backend and API development using C#. He designed and implemented a Headers property for HostedMcpServerTool, ensuring all HTTP calls could include custom and authorization headers for secure, compliant integration with remote MCP servers. Elliot updated OpenAIResponsesChatClient to propagate these headers consistently, reducing the risk of missing critical information in remote requests. His work included extensive unit testing across multiple .NET frameworks and thorough documentation, resulting in improved code clarity, maintainability, and integration reliability. The changes enhanced both configurability and security for MCP tool interactions.