HandMirrorMcp

A Model Context Protocol (MCP) server for .NET assembly and NuGet package inspection. HandMirror helps AI coding agents understand .NET APIs accurately and resolve build errors by providing direct access to assembly metadata and NuGet package information.

AI coding assistants often hallucinate or guess API details, leading to build errors and wasted development iterations. HandMirror solves this by:

- Providingaccurate, version-specific API informationdirectly from assemblies
- Enablingverification of method signatures, types, and namespacesbefore writing code
- Helpingdiagnose and fix .NET build errorsquickly
- Supporting analysis ofnative interop(P/Invoke, COM) dependencies

- inspect_assembly- Full analysis of all public types, members, and attributes with XML documentation
- list_namespaces- List all namespaces in an assembly
- get_type_info- Get detailed information about a specific type

- search_nuget_packages- Search for packages by keyword
- get_nuget_package_info- Get package metadata and dependencies
- get_nuget_package_versions- List all available versions
- inspect_nuget_package- Analyze assemblies in a package
- inspect_nuget_package_type- Get detailed type info from a package
- list_nuget_sources- List configured NuGet package sources
- clear_nuget_cache- Clear the local NuGet package cache
- get_nuget_vulnerabilities- Check for known security vulnerabilities
- inspect_nupkg_contents- Inspect contents of a .nupkg file
- extract_nupkg_file- Extract specific files from a .nupkg

- inspect_native_dependencies- Find P/Invoke (DllImport/LibraryImport) and COM types in an assembly

- analyze_csproj- Analyze .NET project files and identify issues
- analyze_solution- Analyze solution files
- explain_build_error- Get explanations for common build errors
- analyze_file_based_app- Analyze file-based apps
- analyze_config_file- Analyze configuration files
- analyze_packages_config- Analyze packages.config files

- get_system_info- Get system information (OS, .NET runtime, hardware)
- get_dotnet_info- Get detailed .NET installation information

- .NET 8.0 SDKor later
- MCP-compatible client (e.g., Claude Desktop, VS Code with Copilot)

git clone https://github.com/rkttu/HandMirrorMcp.git cd HandMirrorMcp dotnet build

{ "mcpServers": { "handmirror": { "command": "dotnet", "args": ["run", "--project", "C:\\path\\to\\HandMirrorMcp"] } } }

{ "mcpServers": { "handmirror": { "command": "C:\\path\\to\\HandMirrorMcp\\bin\\Debug\\net8.0\\HandMirrorMcp.exe" } } }

Add to your VS Code settings or workspace settings:

{ "servers": { "handmirror": { "command": "dotnet", "args": ["run", "--project", "/path/to/HandMirrorMcp"] } } }

When you need to use an unfamiliar .NET API:

Use inspect_nuget_package_type to show me the HttpClient class from System.Net.Http

When you encounter errors likeCS0246,CS1061, orCS7036:

I'm getting CS1061 error. Use inspect_nuget_package to check the Newtonsoft.Json package and show me the available methods on JObject

Search for packages related to "json serialization" and show me the top results

Check if there are any known vulnerabilities in System.Text.Json version 6.0.0

Analyze my .csproj file at C:\MyProject\MyProject.csproj and identify any issues

HandMirrorMcp/ ├── Constants/ │ └── Emoji.cs # Unicode emoji constants for output formatting ├── Prompts/ │ ├── AssemblyInspectorPrompts.cs │ └── NuGetInspectorPrompts.cs ├── Services/ │ ├── NuGetService.cs # NuGet package operations │ ├── PeAnalyzerService.cs # PE file analysis │ ├── RepositoryService.cs # Repository operations │ └── XmlDocService.cs # XML documentation parsing ├── Tools/ │ ├── AssemblyInspectorTool.cs │ ├── InteropInspectorTool.cs │ ├── NuGetInspectorTool.cs │ ├── ProjectAnalyzerTool.cs │ └── SystemInfoTool.cs └── Program.cs

The tests use MSTest and connect to the actual MCP server for integration testing.

- ModelContextProtocol- MCP server implementation
- Microsoft.Extensions.Hosting- .NET hosting abstractions
- Mono.Cecil- .NET assembly inspection
- NuGet.Protocol- NuGet package operations

This project is licensed under the Apache License 2.0 - see theLICENSEfile for details.

- Model Context Protocolfor the MCP specification
- Mono.Cecilfor .NET assembly inspection capabilities
- The .NET community for continuous inspiration

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