roslyn-codex.mcp 1.3.0

.NET 9.0 This package targets .NET 9.0. The package is compatible with this framework or higher.
The owner has unlisted this package. This could mean that the package is deprecated, has security vulnerabilities or shouldn't be used anymore. 
dotnet tool install --global roslyn-codex.mcp --version 1.3.0
This package contains a .NET tool you can call from the shell/command line. 
dotnet new tool-manifest
                    


                            if you are setting up this repo
                        

                    

                
dotnet tool install --local roslyn-codex.mcp --version 1.3.0
This package contains a .NET tool you can call from the shell/command line. 
#tool dotnet:?package=roslyn-codex.mcp&version=1.3.0
                    


                    

                
nuke :add-package roslyn-codex.mcp --version 1.3.0

roslyn-codex

A Model Context Protocol (MCP) server providing semantic C# codebase analysis via Microsoft Roslyn. Enables AI assistants to navigate types, methods, references, call graphs, and inheritance hierarchies with full compiler-level accuracy.

Installation

roslyn-codex is distributed as a .NET tool via NuGet. This means:

  • One command to install
  • Automatic PATH setup
  • Easy updates with dotnet tool update
  • Works on Windows, macOS, and Linux
dotnet tool install --global roslyn-codex.mcp

The tool is installed to ~/.dotnet/tools and added to your PATH. You can run it from anywhere:

roslyn-codex --help

Updating

dotnet tool update --global roslyn-codex.mcp

Local Tool (Version-Pinned for Teams)

For team projects where everyone needs the same version:

cd YourProject
dotnet new tool-manifest                    # Creates .config/dotnet-tools.json
dotnet tool install roslyn-codex.mcp        # Installs and pins version

The manifest file (.config/dotnet-tools.json) should be committed to source control:

{
  "version": 1,
  "isRoot": true,
  "tools": {
    "roslyn-codex.mcp": {
      "version": "1.2.0",
      "commands": ["roslyn-codex"]
    }
  }
}

Team members restore the pinned version after clone/pull:

dotnet tool restore

MCP Configuration

MCP servers are configured in JSON files. The location depends on your MCP client:

Claude Desktop

Platform Configuration File
macOS ~/Library/Application Support/Claude/claude_desktop_config.json
Windows %APPDATA%\Claude\claude_desktop_config.json

Claude Code (CLI)

Use the claude mcp add command (recommended):

claude mcp add roslyn-codex --command roslyn-codex

Or manually edit the MCP configuration:

Scope Configuration File
Project .mcp.json in project root
User ~/.claude/mcp.json

Configuration Examples

Global tool installation (simplest):

{
  "mcpServers": {
    "roslyn-codex": {
      "command": "roslyn-codex"
    }
  }
}

Local tool installation (for version-pinned projects):

{
  "mcpServers": {
    "roslyn-codex": {
      "command": "dotnet",
      "args": ["tool", "run", "roslyn-codex"]
    }
  }
}

With explicit solution path:

{
  "mcpServers": {
    "roslyn-codex": {
      "command": "roslyn-codex",
      "args": ["--solution", "/path/to/Your.sln"]
    }
  }
}

The server auto-discovers .sln files in the current or parent directories if no path is specified.

How NuGet Distribution Works

Package Sources

NuGet packages can come from multiple sources:

Source URL Use Case
NuGet.org https://nuget.org Public packages (production)
Local folder C:\path\to\packages Development/testing
Private feed Azure Artifacts, GitHub Packages Enterprise/team packages

Global vs Local Tools

Aspect Global Tool Local Tool
Install location ~/.dotnet/tools Project's .config/dotnet-tools.json
Scope Machine-wide Per-project
Version control User manages updates Project controls version
Install command dotnet tool install --global dotnet tool install (in project)
Run command roslyn-codex dotnet tool run roslyn-codex
Best for Personal machines Teams, CI/CD

Version Management

# Check installed version
dotnet tool list --global

# Update to latest
dotnet tool update --global roslyn-codex.mcp

# Install specific version
dotnet tool install --global roslyn-codex.mcp --version 1.2.0

# Downgrade (uninstall first)
dotnet tool uninstall --global roslyn-codex.mcp
dotnet tool install --global roslyn-codex.mcp --version 1.0.0

Features

20 Semantic Analysis Tools

Category Tools
Navigation roslyn_get_status, roslyn_find_type, roslyn_get_type_info, roslyn_find_method, roslyn_get_file_types, roslyn_get_namespaces, roslyn_get_projects
References roslyn_find_usages, roslyn_get_callers, roslyn_get_callees, roslyn_get_dependencies, roslyn_get_dependents
Content Search roslyn_search_content (XML docs, comments, string literals)
Hierarchy roslyn_get_hierarchy, roslyn_get_implementations, roslyn_get_overrides, roslyn_find_by_attribute
Source Access roslyn_get_definition, roslyn_get_source
Analysis roslyn_analyze_dependencies, roslyn_get_statistics

Key Capabilities

  • Live Analysis: Maintains a live Roslyn workspace that updates automatically when files change
  • Semantic Accuracy: Full compiler-level understanding of types, generics, overloads, and inheritance
  • Cross-Project: Analyzes entire solutions with multiple projects
  • Pattern Matching: Find types/methods using wildcards (*Service) or regex (/.*Controller$/)
  • Call Graphs: Trace callers and callees through the codebase
  • Impact Analysis: Find all usages before refactoring

Pattern Matching

All search tools support three pattern types:

Pattern Type Example Matches
Exact MyClass Case-insensitive exact match
Wildcard *Service, Get*, I*able * = any chars, ? = single char
Regex /.*Controller$/ Full regex (enclosed in /)

Command Line Options

Option Description
--solution, -s Path to solution file (.sln)
--project, -p Path to project file (.csproj)
--no-watch Disable file system watching
--help, -h Show help message

Requirements

  • .NET 9.0 SDK or later
  • Visual Studio 2022 or .NET SDK with MSBuild

Troubleshooting

Problem Solution
roslyn-codex not found Ensure ~/.dotnet/tools is in PATH, or restart terminal
"Could not locate MSBuild" Install Visual Studio or .NET SDK
Slow initial load Normal for large solutions; subsequent queries are fast
Stale data after file changes Check file watcher logs or restart server

Development

# Clone and build
git clone https://github.com/stoicstudio/RoslynCodex.Mcp
cd RoslynCodex.Mcp
dotnet build

# Run tests (109 Ouroboros self-analysis tests)
dotnet test

# Run directly from source
dotnet run --project src/RoslynCodex.Mcp -- --solution /path/to/Your.sln

License

MIT

Product Compatible and additional computed target framework versions.
.NET net9.0 is compatible.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed.  net10.0 was computed.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

This package has no dependencies.

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