Microsoft Releases MCP C# SDK 1.0 for AI Agent Development and Authorization Management

The Model Context Protocol, or MCP, is an open protocol that gives AI applications a standardized interface for connecting to external data, tools and services. Microsoft and Anthropic maintain the official C# SDK. Version 1.0 marks the API’s transition to stability and could reduce the integration and maintenance burden for .NET developers building MCP clients, servers and AI agents.

Microsoft released MCP C# SDK 1.0 on March 5, 2026, with full support for the November 25, 2025, MCP specification. The update adds incremental OAuth 2.0 consent, authorization server discovery, tool calls through Sampling and experimental Tasks. It also supports tracking, cancellation and result retrieval for long-running operations. The release is an open-source software update, and no pricing or transaction value was disclosed.