Worked on the dotnet/extensions repository to deliver robust HTTP header support for MCP tooling, focusing on backend development and API design using C#. Designed and implemented a Headers property for HostedMcpServerTool, enabling secure and configurable integration with remote MCP servers by ensuring all HTTP calls include necessary headers. Updated OpenAIResponsesChatClient to propagate these headers consistently, reducing the risk of missing authorization or custom headers. Emphasized reliability through extensive unit testing across multiple .NET frameworks, validating header round-tripping and default behaviors. Improved code maintainability and clarity with refactoring and enhanced documentation, resulting in more secure and reliable MCP tool integrations.