# csharp-sdk [Health: Active]

**Category:** 💻 Developer Tools  
**Repository:** https://github.com/modelcontextprotocol/csharp-sdk  
**GitHub Stars:** 4595  
**Views:** 0  
**Installs:** 0  
**Upvotes:** 0  
**Directory Page:** https://allmcps.com/mcp/csharp-sdk

## Description
The official C# SDK for Model Context Protocol servers and clients. Maintained in collaboration with Microsoft.

## Claude Desktop Quick Installation
No confirmed install details yet, so no config is published. Follow the setup steps in the repository above.

## Documentation

## What csharp-sdk does

The csharp-sdk MCP server is the official C# software development kit for the Model Context Protocol. It lets .NET applications, services, and libraries implement MCP servers or interact with MCP clients. The project is maintained in collaboration with Microsoft and is distributed through several NuGet packages.

MCP standardizes how applications provide context, data sources, and tools to large language models. This SDK is therefore a development dependency rather than a ready-made connector to a specific external service. It provides the APIs needed to add MCP support to a C# codebase.

As a listing in the 💻 Developer Tools category, it fits teams building MCP-aware software in the .NET ecosystem rather than developers looking for a standalone server with preconfigured business integrations.

## How it works

Package selection determines the scope of the implementation. `ModelContextProtocol.Core` contains client and low-level server APIs with the minimum dependency set. `ModelContextProtocol` adds hosting and dependency-injection extensions and references the core package; the README identifies it as the usual choice for projects that do not need HTTP server capabilities.

For HTTP-based MCP servers, `ModelContextProtocol.AspNetCore` builds on the main package. `ModelContextProtocol.Extensions.Apps` adds support for interactive UI applications rendered inside MCP hosts. `ModelContextProtocol.Extensions.Tasks` supports long-running tool invocations, asynchronous execution, status polling, and input requests.

The csharp-sdk MCP server also supports the Identity Assertion Authorization Grant flow through `IdentityAssertionGrantProvider`. This capability is documented as support for cross-application access and requires following the SDK's transport and authorization guidance.

## Setup and configuration

Install the NuGet package that matches the application’s needs. Use the core package when only client or low-level server APIs are required, the main package for hosting and dependency injection, and the ASP.NET Core package for HTTP servers. Add the Apps or Tasks extension packages only when those capabilities are part of the application.

The official Getting Started documentation provides installation instructions, package-selection guidance, and complete client and server examples. The repository also provides a samples directory and API documentation for implementation details. No required environment variables or standalone runtime configuration are specified in the supplied material.

## Tools and capabilities

The csharp-sdk MCP server provides building blocks for:

- Implementing MCP clients in .NET applications, services, and libraries.
- Implementing MCP servers with core or hosted APIs.
- Adding hosting and dependency-injection extensions.
- Creating HTTP-based MCP servers with ASP.NET Core.
- Building interactive MCP Apps for rendering inside MCP hosts.
- Running long tool invocations asynchronously with MCP Tasks, status polling, and input requests.
- Supporting the Identity Assertion Authorization Grant flow through `IdentityAssertionGrantProvider`.

These are SDK capabilities for developers to compose into an application; the supplied material does not describe a fixed catalog of external service tools.

## Limitations and notes

The csharp-sdk MCP server does not represent a named third-party service integration in the supplied documentation. It is an SDK for creating or connecting MCP applications, so the resulting tools, resources, and prompts depend on the client or server implementation built with it.

HTTP server support is separated into `ModelContextProtocol.AspNetCore`, while the main package is intended for projects that do not need HTTP server capabilities. Consult the API reference and conceptual documentation for version-specific APIs and transport details.

The project is licensed under Apache License 2.0.

_Full upstream README: https://allmcps.com/mcp/csharp-sdk/readme_