MCP C# SDK
The official C# SDK for the Model Context Protocol, maintained with Microsoft, letting .NET applications, services and libraries implement and interact with MCP clients and servers.
The MCP C# SDK is the official C# implementation of the Model Context Protocol, an open protocol that standardizes how applications provide context to large language models and lets them integrate securely with data sources and tools. It is organized into packages so a project can take only what it needs.
ModelContextProtocol.Core covers the client and low-level server APIs with minimal dependencies; ModelContextProtocol adds hosting and dependency-injection extensions for most projects; ModelContextProtocol.AspNetCore supports HTTP-based MCP servers; and separate extension packages add MCP Apps, for interactive UIs inside MCP hosts, and MCP Tasks, for running long tool invocations asynchronously with status polling. The SDK also supports the Identity Assertion Authorization Grant flow for cross-application access.