GitHub PR Diff MCP server

The GitHub MCP server provides functionality to extract diffs from Pull Requests using the GitHub API, allowing you to programmatically access and process PR changes. The server is built with the Highlight AI MCP SDK and offers simple API endpoints to extract diff content.

Authentication Setup

Before using the GitHub MCP server, you need to set up authentication:

1. Create a GitHub Personal Access Token with appropriate permissions:

   • For private repositories: token needs repo scope
   • For public repositories: token with public_repo scope is sufficient

2. Set the token as an environment variable:

   export GITHUB_TOKEN=<your-github-token>
   

Available Tools

get_diff_pr

This tool retrieves the diff content from a GitHub Pull Request.

Parameters:

• owner: Repository owner/organization name
• repo: Repository name
• pr_number: Pull Request number

Returns:

• An object containing content - a string with the PR diff

Example usage:

const response = await mcp.get_diff_pr({
  owner: "octocat",
  repo: "hello-world",
  pr_number: 123
});

console.log(response.content);

Error Handling

The server handles various error conditions gracefully:

• Authentication errors: If your GitHub token is missing or invalid, you'll receive an ErrorCode.AuthenticationError
• Invalid parameters: If repository details are incorrect, you'll receive an ErrorCode.InvalidParams
• Not found errors: Non-existent PRs will return ErrorCode.NotFound
• API failures: Other GitHub API issues return formatted error messages

Limitations

When using the GitHub MCP server, be aware of these limitations:

• GitHub API rate limits apply to all requests
• Large diffs may be truncated according to GitHub API restrictions
• Your token must have appropriate permissions for the repositories you're accessing

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 "github-pr-diff" '{"command":"npx","args":["-y","highlight-github-mcp"]}'

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": {
        "github-pr-diff": {
            "command": "npx",
            "args": [
                "-y",
                "highlight-github-mcp"
            ]
        }
    }
}

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": {
        "github-pr-diff": {
            "command": "npx",
            "args": [
                "-y",
                "highlight-github-mcp"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect