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A local MCP server that exposes IDE-like semantic queries over a C# workspace.

Coding agents these days are remarkably powerful, and often the best way to help them is to stay out of their way. RoslynQuery implements a small set of versatile commands that fill in the gaps in the text-oriented workflow without polluting the context.

Installation

Roslyn compiler/workspace libraries are bundled with the app, but real .sln, .slnx, and .csproj loading depends on the machine's installed MSBuild/.NET SDK through Microsoft.Build.Locator.

You can either:

• Download the server executable from the releases page, or...
• Build it locally with dotnet publish.

To update an installed release binary in place:

roslynquery -U

Now point your editor at the MCP executable:

For a basic stdio setup, add this to config.toml:

stdio | Windows (Native)

[mcp_servers.roslyn]
command = "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe"
cwd = "C:\\src\\RoslynQuery"
disabled_tools = []
tool_timeout_sec = 1800
enabled = true

stdio | Windows (WSL)

[mcp_servers.roslyn]
command = "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe"
cwd = "/mnt/c/src/RoslynQuery"
disabled_tools = []
tool_timeout_sec = 1800
enabled = true

stdio | Linux

[mcp_servers.roslyn]
command = "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery"
cwd = "/home/you/src/RoslynQuery"
disabled_tools = []
tool_timeout_sec = 1800
enabled = true

Claude Code adds MCP servers with claude mcp add.

stdio | Windows (Native)

claude mcp add --transport stdio roslyn -- C:\src\RoslynQuery\RoslynQuery.Server\publish\win-x64\roslynquery.exe

stdio | Windows (WSL)

claude mcp add --transport stdio roslyn -- /mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe

stdio | Linux

claude mcp add --transport stdio roslyn -- /home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery

Cursor uses mcp.json with a top-level mcpServers object. You can put it in ~/.cursor/mcp.json for a global setup or .cursor/mcp.json for a project-local setup.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe"
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe"
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery"
    }
  }
}

Windsurf stores MCP servers in ~/.codeium/windsurf/mcp_config.json.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": []
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": []
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": []
    }
  }
}

Cline stores MCP settings in cline_mcp_settings.json.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": [],
      "disabled": false
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": [],
      "disabled": false
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": [],
      "disabled": false
    }
  }
}

Continue uses YAML, typically as standalone files under .continue/mcpServers/

Create .continue/mcpServers/roslyn.yaml:

stdio | Windows (Native)

name: RoslynQuery
version: 0.0.1
schema: v1
mcpServers:
  - name: roslyn
    type: stdio
    command: C:\src\RoslynQuery\RoslynQuery.Server\publish\win-x64\roslynquery.exe
    cwd: C:\src\RoslynQuery

stdio | Windows (WSL)

name: RoslynQuery
version: 0.0.1
schema: v1
mcpServers:
  - name: roslyn
    type: stdio
    command: /mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe
    cwd: /mnt/c/src/RoslynQuery

stdio | Linux

name: RoslynQuery
version: 0.0.1
schema: v1
mcpServers:
  - name: roslyn
    type: stdio
    command: /home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery
    cwd: /home/you/src/RoslynQuery

Gemini CLI stores MCP configuration in ~/.gemini/settings.json for user scope or .gemini/settings.json for project scope.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "cwd": "C:\\src\\RoslynQuery"
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "cwd": "/mnt/c/src/RoslynQuery"
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "cwd": "/home/you/src/RoslynQuery"
    }
  }
}

Equivalent CLI commands:

Local stdio

gemini mcp add roslyn /home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery

GitHub Copilot CLI stores MCP servers in ~/.copilot/mcp-config.json.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "type": "local",
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": [],
      "env": {},
      "tools": ["*"]
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "type": "local",
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": [],
      "env": {},
      "tools": ["*"]
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "type": "local",
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": [],
      "env": {},
      "tools": ["*"]
    }
  }
}

Interactive alternative:

/mcp add

VS Code uses mcp.json with a top-level servers object. For workspace scope, put it in .vscode/mcp.json; for user scope, open the user MCP configuration from the Command Palette.

stdio | Windows (Native)

{
  "servers": {
    "roslyn": {
      "type": "stdio",
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": []
    }
  }
}

stdio | Windows (WSL)

{
  "servers": {
    "roslyn": {
      "type": "stdio",
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": []
    }
  }
}

stdio | Linux

{
  "servers": {
    "roslyn": {
      "type": "stdio",
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": []
    }
  }
}

You can get to the config file from Manage MCP Servers → View raw config.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": [],
      "cwd": "C:\\src\\RoslynQuery"
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": [],
      "cwd": "/mnt/c/src/RoslynQuery"
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": [],
      "cwd": "/home/you/src/RoslynQuery"
    }
  }
}

Zed uses context_servers in its settings. For project scope, put this in .zed/settings.json; for user scope, add it to your user settings.

stdio | Windows (Native)

{
  "context_servers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": []
    }
  }
}

stdio | Windows (WSL)

{
  "context_servers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": []
    }
  }
}

stdio | Linux

{
  "context_servers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": []
    }
  }
}

Roo Code stores global MCP configuration in mcp_settings.json. For project-local setup, create .roo/mcp.json.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": [],
      "cwd": "C:\\src\\RoslynQuery",
      "disabled": false
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": [],
      "cwd": "/mnt/c/src/RoslynQuery",
      "disabled": false
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": [],
      "cwd": "/home/you/src/RoslynQuery",
      "disabled": false
    }
  }
}

Junie in JetBrains IDEs and Junie CLI use the same MCP config file format. Use ~/.junie/mcp/mcp.json for user scope or .junie/mcp/mcp.json in the project root for project scope.

stdio | Windows (Native)

{
  "mcpServers": {
    "roslyn": {
      "command": "C:\\src\\RoslynQuery\\RoslynQuery.Server\\publish\\win-x64\\roslynquery.exe",
      "args": []
    }
  }
}

stdio | Windows (WSL)

{
  "mcpServers": {
    "roslyn": {
      "command": "/mnt/c/src/RoslynQuery/RoslynQuery.Server/publish/win-x64/roslynquery.exe",
      "args": []
    }
  }
}

stdio | Linux

{
  "mcpServers": {
    "roslyn": {
      "command": "/home/you/src/RoslynQuery/RoslynQuery.Server/publish/linux-x64/roslynquery",
      "args": []
    }
  }
}

Implemented Tools

Workspace lifecycle

• load_workspace: Opens the solution/project for analysis. Accepts a directory path, .sln, .slnx, or .csproj. Calling it again with the same path reloads the workspace from disk.

To exclude projects from analsis, create a .roslynqueryignore file next to the solution file. Add one project pattern per line. Patterns support * and ? globs, and negation with !. This can improve the initial load performance.

Assembly-CSharp-Editor.csproj
Assembly-CSharp-Editor-firstpass.csproj
*Editor.csproj
*Tests.csproj
Unity.Services*.csproj
Unity.Searcher*.csproj
Unity.Recorder*.csproj
Unity.ProBuilder*.csproj
Unity.Polybrush*.csproj
Unity.Multiplayer.Center*.csproj
Unity.MemoryProfiler*.csproj

• status: Lists loaded projects.

• show_diagnostics: Lists workspace compilation diagnostics on demand, with an optional verbosity parameter.

Search and analysis

• describe_symbol: Returns a set of useful details for a symbol.

• list_type_members: Lists members of a type symbol, optionally including inherited members.

• find_usages: Finds source references to a resolved symbol across the loaded workspace.

• find_related_symbols: Finds related symbols such as base types, implemented interfaces, derived types, implementations, overrides, overridden members, and containing symbols.

• view_il: Displays a compact view of a method's compiled IL representation.

Agent guidance

The tool descriptions themselves should be enough to get you started out-of-the-box. If you want to, you can also include something like this in your agent instructions:

When working with C# solutions, use the Roslyn MCP tools to search and inspect symbols.
Start with `load_workspace`.