DotNet Types Explorer MCP server for AI agents

The .NET Types Explorer MCP Server is a powerful tool that enables AI coding agents to understand and work with .NET codebases by providing detailed type information from compiled assemblies. It offers a structured approach to exploring .NET projects through assemblies, namespaces, and types, making it easier to generate accurate code suggestions.

Prerequisites

.NET 9.0 SDK or later
A .NET project that you want to explore

Installation

To install the .NET Types Explorer MCP Server:

Clone the repository
Build the project:
```
dotnet build -c Release
```
Publish the project:
```
dotnet publish -c Release -r <runtime-identifier> --self-contained false
```
Replace <runtime-identifier> with your target platform (e.g., win-x64, linux-x64, osx-x64).

Configuration

To use the server with an AI agent, configure it in your MCP settings file:

{
  "mcpServers": {
    "dotnet-types-explorer": {
      "command": "/path/to/DotNetMetadataMcpServer",
      "args": [ "--homeEnvVariable", "/home/user" ],
      "disabled": false,
      "alwaysAllow": [],
      "timeout": 300
    }
  }
}

Replace /path/to/DotNetMetadataMcpServer with the actual path to the published executable, and /home/user with your home directory.

Important Limitations

The project must be built before scanning. The server relies on compiled assemblies to extract type information.
The tool doesn't follow references to other projects. It only inspects the specified project and its NuGet dependencies.

Available Tools

The server provides five main tools for AI agents:

ReferencedAssembliesExplorer

Retrieves referenced assemblies from a .NET project.

Input Schema:

{
  "ProjectFileAbsolutePath": "string",
  "PageNumber": "integer",
  "FullTextFiltersWithWildCardSupport": ["string"]
}

NamespacesExplorer

Retrieves namespaces from specified assemblies.

Input Schema:

{
  "ProjectFileAbsolutePath": "string",
  "AssemblyNames": ["string"],
  "PageNumber": "integer",
  "FullTextFiltersWithWildCardSupport": ["string"]
}

NamespaceTypes

Retrieves types from specified namespaces.

Input Schema:

{
  "ProjectFileAbsolutePath": "string",
  "Namespaces": ["string"],
  "PageNumber": "integer",
  "FullTextFiltersWithWildCardSupport": ["string"]
}

NuGetPackageSearch

Searches for NuGet packages on nuget.org with filtering and pagination.

Input Schema:

{
  "SearchQuery": "string",
  "IncludePrerelease": "boolean",
  "PageNumber": "integer",
  "FullTextFiltersWithWildCardSupport": ["string"]
}

NuGetPackageVersions

Retrieves version history and dependency information for specific NuGet packages.

Recommended Workflow

When working with a .NET project:

Ensure the project is built first
Use ReferencedAssembliesExplorer to retrieve all assemblies referenced by the project
Focus on third-party libraries and NuGet packages
Use NamespacesExplorer to discover the namespaces within those assemblies
Use NamespaceTypes to retrieve detailed information about the types within namespaces of interest
Use filtering when needed to narrow down results
Use NuGetPackageSearch to find specific packages
Use NuGetPackageVersions to get detailed information about package versions and dependencies

This top-down approach (assemblies → namespaces → types) provides an efficient way to explore and understand .NET libraries when writing code that uses them.

Integration with AI Coding Assistants

This server has been tested with the Roo Code Visual Studio extension, an AI coding assistant that supports the Model Context Protocol. You can use a .clinerules file to instruct your coding assistant to use the MCP server.

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "dotnet-types-explorer" '{"command":"/path/to/DotNetMetadataMcpServer","args":["--homeEnvVariable","/home/user"],"disabled":false,"alwaysAllow":[],"timeout":300}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "dotnet-types-explorer": {
            "command": "/path/to/DotNetMetadataMcpServer",
            "args": [
                "--homeEnvVariable",
                "/home/user"
            ],
            "disabled": false,
            "alwaysAllow": [],
            "timeout": 300
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "dotnet-types-explorer": {
            "command": "/path/to/DotNetMetadataMcpServer",
            "args": [
                "--homeEnvVariable",
                "/home/user"
            ],
            "disabled": false,
            "alwaysAllow": [],
            "timeout": 300
        }
    }
}

3. Restart Claude Desktop for the changes to take effect