roslyn-mcp

Roslyn Code Analysis MCP Server

Overview

A Model Context Protocol (MCP) server that provides C# code analysis capabilities using the Roslyn compiler platform. This tool helps validate C# files, find symbol references, and perform static code analysis within the context of a .NET project.

Features

• Code Validation: Analyze C# files for syntax errors, semantic issues, and compiler warnings
• Symbol Reference Finding: Locate all usages of a symbol across a project
• Project Context Analysis: Validate files within their project context
• Code Analyzer Support: Run Microsoft recommended code analyzers

Tools

• ValidateFile: Validates a C# file using Roslyn and runs code analyzers
• FindUsages: Finds all references to a symbol at a specified position

Example config

{
    "servers": {
        "RoslynMCP": {
            "type": "stdio",
            "command": "dotnet",
            "args": [
                "run",
                "--no-build",
                "--project",
                "E:/Source/roslyn-mcp/RoslynMCP/RoslynMCP/RoslynMCP.csproj"
            ]
        }
    }
}

Example prompt

When done implementing changes, run these validation steps as human will not accept work unless these are done:
- Always use Roslyn validation tool on C# (.cs) files

Getting Started

1. Build the project
2. Run the application with:

   dotnet run
   

3. The server will start and listen for MCP commands via standard I/O

Requirements

• .NET SDK
• MSBuild tools
• NuGet packages for Roslyn analyzers (automatically loaded if available)

Example Usage

Validate a C# file:

ValidateFile --filePath="/path/to/your/file.cs" --runAnalyzers=true

Find all usages of a symbol:

FindUsages --filePath="/path/to/your/file.cs" --line=10 --column=15

Technical Details

• Uses Microsoft.CodeAnalysis libraries for code analysis
• Integrates with MSBuild to load full project context
• Supports standard diagnostic analyzers
• Includes detailed output with syntax, semantic, and analyzer diagnostics