Microsoft has partnered with Anthropic to develop an official C# SDK for the Model Context Protocol (MCP), an open protocol designed to connect large language models (LLMs) with external tools and data sources.
The SDK is open-source and available under the modelcontextprotocol GitHub organization.
The C# SDK is based on an existing community project called mcpdotnet, originally started by Peder Holdgaard Pederson.
Microsoft acknowledged the groundwork laid by Pederson and other contributors, which helped shape the foundation for this release.
The protocol supports a variety of standard messages for tool execution and resource access, such as ListToolsRequest, CallToolRequest, and ReadResourceRequest.
Some developers have raised questions about authentication support, including OAuth and OpenID Connect.
The SDK aims to take advantage of modern .NET runtime improvements and is intended to build clients and servers in the MCP ecosystem.