csharp-sdk

Name: csharp-sdk
Author: modelcontextprotocol

Warning

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

4,480stars

786forks

Installation

# Add to your Claude Code skills
git clone https://github.com/modelcontextprotocol/csharp-sdk

Getting Started

Guides for using mcp servers skills like csharp-sdk.

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Security ReportWarning

Last scanned: 4/20/2026

{
  "issues": [
    {
      "type": "npm-audit",
      "message": "@hono/node-server: @hono/node-server: Middleware bypass via repeated slashes in serveStatic",
      "severity": "medium"
    },
    {
      "type": "npm-audit",
      "message": "express-rate-limit: express-rate-limit: IPv4-mapped IPv6 addresses bypass per-client rate limiting on servers with dual-stack network",
      "severity": "high"
    },
    {
      "type": "npm-audit",
      "message": "hono: Hono vulnerable to Prototype Pollution possible through __proto__ key allowed in parseBody({ dot: true })",
      "severity": "medium"
    },
    {
      "type": "npm-audit",
      "message": "path-to-regexp: path-to-regexp vulnerable to Denial of Service via sequential optional groups",
      "severity": "high"
    },
    {
      "type": "npm-audit",
      "message": "undici: Undici: Malicious WebSocket 64-bit length overflows parser and crashes the client",
      "severity": "high"
    },
    {
      "type": "npm-audit",
      "message": "yaml: yaml is vulnerable to Stack Overflow via deeply nested YAML collections",
      "severity": "medium"
    }
  ],
  "status": "WARNING",
  "scannedAt": "2026-04-20T06:15:04.638Z",
  "semgrepRan": false,
  "npmAuditRan": true,
  "pipAuditRan": true
}

README.md

Frequently Asked Questions

What is csharp-sdk?

csharp-sdk is an open-source mcp servers skill for AI coding assistants such as Claude Code, Codex CLI, and ChatGPT, built by modelcontextprotocol. The official C# SDK for Model Context Protocol servers and clients. Maintained in collaboration with Microsoft. It has 4,480 GitHub stars.

Is csharp-sdk safe to use?

csharp-sdk returned warnings in SkillsLLM's automated security scan. It has no critical vulnerabilities, but review the flagged issues in the Security Report section before adding it to your workflow.

How do I install csharp-sdk?

Clone the repository with "git clone https://github.com/modelcontextprotocol/csharp-sdk" and add it to your Claude Code skills directory (see the Installation section above).

What programming language is csharp-sdk written in?

csharp-sdk is primarily written in C#. It is open-source under modelcontextprotocol on GitHub, so you can review or fork the full source.

Are there alternatives to csharp-sdk?

Yes. SkillsLLM lists many other MCP Servers skills you can browse and compare side by side. Open the MCP Servers category from the badge at the top of this page, or use the Related Skills and comparison links further down to weigh csharp-sdk against similar tools.

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⚠️ Third-Party Software Notice

This skill is third-party open-source software developed and hosted independently on GitHub. SkillsLLM is an informational directory and does not control or maintain the underlying repository.

Any security checks, ratings, or warnings displayed by SkillsLLM are automated and limited in scope. They do not constitute a security certification or guarantee that the software is safe, error-free, or free from malicious code, vulnerabilities, compromised dependencies, or prompt-injection risks.

Review the source code, permissions, dependencies, and configuration before installing or running any third-party skill. Use is at your own risk. To the maximum extent permitted by applicable law, SkillsLLM is not liable for losses arising from third-party software.

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MCP C# SDK

The official C# SDK for the Model Context Protocol, enabling .NET applications, services, and libraries to implement and interact with MCP clients and servers. Please visit the API documentation for more details on available functionality.

Packages

The SDK packages are:

ModelContextProtocol.Core - For projects that only need to use the client or low-level server APIs and want the minimum number of dependencies.
ModelContextProtocol - The main package with hosting and dependency injection extensions. References ModelContextProtocol.Core. This is the right fit for most projects that don't need HTTP server capabilities.
ModelContextProtocol.AspNetCore - The library for HTTP-based MCP servers. References ModelContextProtocol.
ModelContextProtocol.Extensions.Apps - MCP Apps extension for building interactive UI applications that render inside MCP hosts.
ModelContextProtocol.Extensions.Tasks - MCP Tasks extension for running long-running tool invocations asynchronously with status polling and input requests.

Getting Started

To get started, see the Getting Started guide in the conceptual documentation for installation instructions, package-selection guidance, and complete examples for both clients and servers.

You can also browse the samples directory and the API documentation for more details on available functionality.

About MCP

The Model Context Protocol (MCP) is an open protocol that standardizes how applications provide context to Large Language Models (LLMs). It enables secure integration between LLMs and various data sources and tools.

For more information about MCP:

Cross-Application Access (Identity Assertion Authorization Grant flow)

The SDK provides support for the Identity Assertion Authorization Grant flow via IdentityAssertionGrantProvider. See the Cross-Application Access section in the transport docs for full usage details.

License

This project is licensed under the Apache License 2.0.