ModelContextProtocol.Core 1.3.0 ModelContextProtocol Apache-2.0 https://licenses.nuget.org/Apache-2.0 logo.png README.md https://csharp.sdk.modelcontextprotocol.io/ Core .NET SDK for the Model Context Protocol (MCP) © Model Context Protocol a Series of LF Projects, LLC. ModelContextProtocol mcp ai llm