CodeQL MCP server

This project allows you to run a Model Context Protocol (MCP) server that wraps the CodeQL query server, enabling tools like Cursor or AI agents to interact with CodeQL through structured commands and document search capabilities.

Installation

Requirements

You'll need to install the required dependencies using either uv or pip:

Using uv:

uv pip install -r requirements.txt

Or using pip:

pip install fastmcp httpx

Prerequisites

• Ensure you have a CodeQL binary in your system PATH
• Alternatively, you can hardcode the CodeQL binary path in codeqlclient.py

Running the Server

Start the MCP server with the following command:

uv run mcp run server.py -t sse

This will:

• Launch the server at http://localhost:8000/sse
• Make it available for Cursor or AI agents to connect

Configuration for Cursor

To enable Cursor to work with your CodeQL MCP server, add the following to your .cursor/config.json file:

{
  "mcpServers": {
    "CodeQL": {
      "url": "http://localhost:8000/sse"
    }
  }
}

Usage

The MCP server supports several key features:

Working with CodeQL Databases

• Register CodeQL databases for analysis

Query Execution

• Run complete CodeQL queries
• Quick-evaluate individual symbols

Results Processing

• Decode .bqrs files into JSON format

Symbol Navigation

• Locate positions of predicate and class symbols in code

Usage Tips

When working with AI tools like Cursor:

• Tools will invoke CodeQL commands via natural language
• Be specific in your prompts about query locations, write locations, and database paths
• The server uses SSE (Server-Sent Events) for communication with clients

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 "CodeQL" '{"url":"http://localhost:8000/sse"}'

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": {
        "CodeQL": {
            "url": "http://localhost:8000/sse"
        }
    }
}

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": {
        "CodeQL": {
            "url": "http://localhost:8000/sse"
        }
    }
}

3. Restart Claude Desktop for the changes to take effect