NuGet Packages MCP Server

A Model Context Protocol (MCP) server that provides tools for searching and retrieving NuGet package information. This server enables AI assistants to interact with NuGet package repositories through standardized MCP tools.

Overview

The NuGet Packages MCP Server is a .NET-based implementation that exposes NuGet package metadata retrieval capabilities through the MCP protocol. It allows AI assistants to:

• Retrieve all available versions of a NuGet package
• Analyze package dependencies for specific versions
• Extract and document public API contracts from packages
• Access package information from any NuGet v3 feed

Features

• Version Discovery: Get all available versions of a package including prerelease versions
• Dependency Analysis: View package dependencies and their version requirements for specific package versions
• API Contract Extraction: Generate markdown documentation of public interfaces and classes from packages
• Package Metadata: Access detailed package information including authors, license, tags, and project URLs
• Flexible Feed Support: Configure to use any NuGet v3 compatible feed (default: nuget.org)
• MCP Protocol Compliance: Full support for MCP tool schemas and communication

Prerequisites

• .NET 8.0 SDK or later
• Node.js (for running the MCP Inspector)
• An MCP-compatible client (e.g., Claude Desktop, Cline VS Code extension)

Installation

1. Clone the repository:

   git clone https://github.com/oshvartz/nuget-packages-mcp-server.git
   cd nuget-packages-mcp-server
   

2. Build the project:

   dotnet build -c Release
   

3. The built DLL will be located at:

   src/NugetPackagesMcpServer/bin/Release/net8.0/NugetPackagesMcpServer.dll
   

Configuration

Adding to MCP Settings

Add the following configuration to your MCP client settings (e.g., cline_mcp_settings.json):

{
  "nuget-packages-mcp-server": {
    "disabled": false,
    "timeout": 300,
    "command": "dotnet",
    "args": [
      "C:/path/to/NugetPackagesMcpServer.dll"
    ],
    "env": {
      "NugetFeed:FeedUrl": "https://api.nuget.org/v3/index.json"
    },
    "type": "stdio"
  }
}

Configuration Options

• timeout: Maximum time (in seconds) for server operations
• NugetFeed:FeedUrl: The NuGet v3 feed URL to use (defaults to nuget.org)

Available Tools

The server provides the following MCP tools:

GetPackageVersions

Get all available versions of a NuGet package from the configured feed.

Parameters:

• packageName (string, required): The name of the NuGet package
• includePrerelease (boolean, optional): Include prerelease versions in results (defaults to feed configuration)

GetPackageDependencies

Get package dependencies for a specific package name and version.

Parameters:

• packageName (string, required): The name of the NuGet package
• version (string, required): The specific version of the package

GetPackageContracts

Get public interfaces and classes contracts from a NuGet package as markdown. This tool extracts and documents the public API surface of a package.

Parameters:

• packageName (string, required): The name of the NuGet package
• version (string, required): The specific version of the package

Returns: A markdown document containing:

• Package metadata (description, authors, tags, license, project URL)
• Public interfaces and classes with their members
• Method signatures and documentation

Testing with MCP Inspector

The repository includes a PowerShell script (test-mcp-inspector.ps1) that uses the official MCP Inspector tool to test and debug the server.

What is MCP Inspector?

MCP Inspector is an official debugging tool from the Model Context Protocol team that provides:

• A web-based interface for testing MCP servers
• Interactive tool invocation and response inspection
• Schema validation and protocol compliance checking
• Real-time server communication monitoring

Running the Inspector

1. Ensure prerequisites are installed:

   • .NET 8.0 SDK
   • Node.js and npm

2. Run the test script:

   .\test-mcp-inspector.ps1
   

3. The script will:

   • Verify all prerequisites
   • Build the project if needed
   • Start the MCP Inspector on http://localhost:3000
   • Launch the NuGet MCP server for testing

Test Script Options

# Use default settings (port 3000, Release build)
.\test-mcp-inspector.ps1

# Use custom port
.\test-mcp-inspector.ps1 -Port 3001

# Use Debug build
.\test-mcp-inspector.ps1 -ServerDll "./src/NugetPackagesMcpServer/bin/Debug/net8.0/NugetPackagesMcpServer.dll"

Using the Inspector

Once running, the MCP Inspector allows you to:

1. View Available Tools: See all tools exposed by the server with their schemas
2. Test Tool Invocations:
   • Select a tool (e.g., GetPackageVersions)
   • Fill in parameters
   • Execute and see the response
3. Inspect Communication: View the raw MCP protocol messages
4. Validate Responses: Ensure responses match expected schemas

Example test scenarios:

• Get all versions of popular packages like "Newtonsoft.Json"
• Check dependencies for a specific version (e.g., "Newtonsoft.Json" version "13.0.3")
• Extract public API contracts from a package
• Test with and without prerelease versions

Development

Project Structure

nuget-packages-mcp-server/
├── src/
│   └── NugetPackagesMcpServer/
│       ├── Configuration/      # Configuration models
│       ├── Models/            # Data models
│       ├── Services/          # NuGet client services
│       ├── Program.cs         # Entry point
│       └── NugetPackagesTool.cs  # MCP tool implementation
├── test-mcp-inspector.ps1     # Testing script
└── README.md

Building from Source

# Debug build
dotnet build

# Release build
dotnet build -c Release

# Run tests (if available)
dotnet test

Troubleshooting

Common Issues

1. Server fails to start:

   • Ensure .NET 8.0 SDK is installed
   • Check the DLL path in your configuration

2. Tool execution fails:

   • Verify the NuGet feed URL is correct
   • Check network connectivity
   • Ensure the package name and version are valid
   • Try with a known package like "Newtonsoft.Json"

3. MCP Inspector issues:

   • Ensure Node.js is installed
   • Check if port 3000 is available
   • Try running with elevated permissions if needed

Debug Logging

The server supports standard .NET logging. Set the logging level in your environment:

set LOGGING__LOGLEVEL__DEFAULT=Debug

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

License

[Add your license information here]

Acknowledgments

• Built using the Model Context Protocol
• Powered by NuGet Client SDK