GitLab MCP for Code Review

This project is forked from cayirtepeomer/gerrit-code-review-mcp and adapted for GitLab integration.

An MCP (Model Context Protocol) server for integrating AI assistants like Claude with GitLab's merge requests. This allows AI assistants to review code changes directly through the GitLab API.

Features

• Complete Merge Request Analysis: Fetch full details about merge requests including diffs, commits, and comments
• File-Specific Diffs: Analyze changes to specific files within merge requests
• Version Comparison: Compare different branches, tags, or commits
• Review Management: Add comments, approve, or unapprove merge requests
• Project Overview: Get lists of all merge requests in a project

Installation

Prerequisites

• Python 3.10+
• GitLab personal access token with API scope (read_api, api)
• Cursor IDE or Claude Desktop App for MCP integration

Quick Start

1. Clone this repository:

git clone https://github.com/lininn/gitlab-code-review-mcp.git
cd gitlab-mcp-code-review

2. Create and activate a virtual environment:

python -m venv .venv
source .venv/bin/activate  # On Windows: .venv\Scripts\activate

3. Install dependencies:

pip install -r requirements.txt

4. Create a .env file with your GitLab configuration (see .env.example for all options):

# Required
GITLAB_TOKEN=your_personal_access_token_here

# Optional settings
GITLAB_HOST=gitlab.com
GITLAB_API_VERSION=v4
LOG_LEVEL=INFO

Configuration Options

The following environment variables can be configured in your .env file:

Variable	Required	Default	Description
GITLAB_TOKEN	Yes	-	Your GitLab personal access token
GITLAB_HOST	No	gitlab.com	GitLab instance hostname
GITLAB_API_VERSION	No	v4	GitLab API version to use
LOG_LEVEL	No	INFO	Logging level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
DEBUG	No	false	Enable debug mode
REQUEST_TIMEOUT	No	30	API request timeout in seconds
MAX_RETRIES	No	3	Maximum retry attempts for failed requests

Cursor IDE Integration

To use this MCP with Cursor IDE, add this configuration to your ~/.cursor/mcp.json file:

{
  "mcpServers": {
    "gitlab-mcp-code-review": {
      "command": "/path/to/your/gitlab-mcp-code-review/.venv/bin/python",
      "args": [
        "/path/to/your/gitlab-mcp-code-review/server.py",
        "--transport",
        "stdio"
      ],
      "cwd": "/path/to/your/gitlab-mcp-code-review",
      "env": {
        "PYTHONPATH": "/path/to/your/gitlab-mcp-code-review",
        "VIRTUAL_ENV": "/path/to/your/gitlab-mcp-code-review/.venv",
        "PATH": "/path/to/your/gitlab-mcp-code-review/.venv/bin:/usr/local/bin:/usr/bin:/bin"
      },
      "stdio": true
    }
  }
}

Replace /path/to/your/gitlab-mcp-code-review with the actual path to your cloned repository.

Claude Desktop App Integration

To use this MCP with the Claude Desktop App:

1. Open the Claude Desktop App
2. Go to Settings → Advanced → MCP Configuration
3. Add the following configuration:

{
  "mcpServers": {
    "gitlab-mcp-code-review": {
      "command": "/path/to/your/gitlab-mcp-code-review/.venv/bin/python",
      "args": [
        "/path/to/your/gitlab-mcp-code-review/server.py",
        "--transport",
        "stdio"
      ],
      "cwd": "/path/to/your/gitlab-mcp-code-review",
      "env": {
        "PYTHONPATH": "/path/to/your/gitlab-mcp-code-review",
        "VIRTUAL_ENV": "/path/to/your/gitlab-mcp-code-review/.venv",
        "PATH": "/path/to/your/gitlab-mcp-code-review/.venv/bin:/usr/local/bin:/usr/bin:/bin"
      },
      "stdio": true
    }
  }
}

Replace /path/to/your/gitlab-mcp-code-review with the actual path to your cloned repository.

Available Tools

The MCP server provides the following tools for interacting with GitLab:

Tool	Description
fetch_merge_request	Get complete information about a merge request
fetch_merge_request_diff	Get diffs for a specific merge request
fetch_commit_diff	Get diff information for a specific commit
compare_versions	Compare different branches, tags, or commits
add_merge_request_comment	Add a comment to a merge request
approve_merge_request	Approve a merge request
unapprove_merge_request	Unapprove a merge request
get_project_merge_requests	Get a list of merge requests for a project

Usage Examples

Fetch a Merge Request

# Get details of merge request #5 in project with ID 123
mr = fetch_merge_request("123", "5")

View Specific File Changes

# Get diff for a specific file in a merge request
file_diff = fetch_merge_request_diff("123", "5", "path/to/file.js")

Compare Branches

# Compare develop branch with master branch
diff = compare_versions("123", "develop", "master")

Add a Comment to a Merge Request

# Add a comment to a merge request
comment = add_merge_request_comment("123", "5", "This code looks good!")

Approve a Merge Request

# Approve a merge request and set required approvals to 2
approval = approve_merge_request("123", "5", approvals_required=2)

Troubleshooting

If you encounter issues:

1. Verify your GitLab token has the appropriate permissions (api, read_api)
2. Check your .env file settings
3. Ensure your MCP configuration paths are correct
4. Test connection with: curl -H "Private-Token: your-token" https://gitlab.com/api/v4/projects
5. Set LOG_LEVEL=DEBUG in your .env file for more detailed logging

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

See the CONTRIBUTING.md file for more details on the development process.

Code Review Standards

This project follows strict code review standards to ensure quality and maintainability:

• 📋 Code Review Guidelines: This project follows a strict set of code review guidelines to ensure quality and consistency. For detailed information on the review process, standards, and best practices, please see the Code Review Guidelines.
• ✅ Review Checklist: All pull requests should be checked against the PULL_REQUEST_CHECKLIST.md before submission.
• 🔄 CI/CD Pipeline: We use GitLab CI for automated quality checks. Ensure all pipeline checks pass before requesting a review.
• 📝 Templates: Please use the provided merge request and issue templates to ensure all necessary information is included.

Quick Start for Contributors

1. Read the Code Review Guidelines
2. Use the appropriate MR template when creating pull requests
3. Ensure all CI checks pass before requesting review
4. Address all reviewer feedback promptly

License

This project is licensed under the MIT License - see the LICENSE file for details.