GitLab MR Comments MCP Server

A Model Context Protocol (MCP) server that fetches merge request comments from GitLab, including file names, line numbers, and comment text.

Features

• Fetches comments from GitLab merge requests via the GitLab API
• Returns structured data with:
  • File name (if comment is on a specific file)
  • Line number (if comment is on a specific line)
  • Comment text
  • Author information
  • Creation timestamp
  • Resolution status
• Supports pagination
• Optional filtering of resolved comments
• SSL verification control

Installation

npm install
npm run build

Configuration

Set the following environment variables:

Required

• GITLAB_HOST or GITLAB_BASE_URL: Your GitLab instance URL (e.g., https://gitlab.com)
• GITLAB_TOKEN or GITLAB_PERSONAL_ACCESS_TOKEN: Your GitLab personal access token

Optional

• GITLAB_SSL_VERIFY: SSL certificate verification. Set to 0, false, or no to disable (default: enabled)

Usage

As an MCP Server

Add to your MCP client configuration (e.g., Claude Desktop, Cline):

{
  "mcpServers": {
    "gitlab-mr-comments": {
      "command": "node",
      "args": ["/path/to/gitlab-mr-comments/dist/index.js"],
      "env": {
        "GITLAB_HOST": "https://gitlab.com",
        "GITLAB_TOKEN": "your-gitlab-token-here"
      }
    }
  }
}

Using with AI Assistants

When you paste a GitLab merge request URL to an AI assistant that has this MCP server configured, the AI should automatically:

1. Parse the URL to extract the project path and MR IID
2. Call the tool with the correct parameters
3. Return the comments in a readable format

Example prompt:

Show me the comments from this merge request:
https://mars-gitlab.systemgroup.net/mars/general-market/-/merge_requests/7380

The AI will extract:

• Project: mars/general-market
• MR IID: 7380

And call the tool accordingly.

Tool: gitlab.get_merge_request_comments

Fetches comments for a specific merge request.

Parameters

• project_id (string): Numeric project ID or full path (e.g., "123" or "mygroup/myproject")
• merge_request_iid (string): Internal IID of the merge request (e.g., "456")
• per_page (number, optional): Number of discussions per page (1-100, default: GitLab default of 20)
• page (number, optional): Page of discussions to fetch (default: 1)
• include_resolved (boolean, optional): Include resolved comments (default: false)

Extracting Parameters from a GitLab URL

Given a merge request URL like:

https://mars-gitlab.systemgroup.net/mars/general-market/-/merge_requests/7380

Extract the parameters as:

• project_id: "mars/general-market" (the path between the domain and /-/merge_requests/)
• merge_request_iid: "7380" (the number after /merge_requests/)

Example:

{
  "project_id": "mars/general-market",
  "merge_request_iid": "7380"
}

Example Response

[
  {
    "file": "src/index.ts",
    "line": 42,
    "text": "Consider refactoring this function for better readability",
    "author": "john.doe",
    "created_at": "2024-11-08T10:30:00.000Z",
    "resolved": false
  },
  {
    "file": "README.md",
    "line": 10,
    "text": "This documentation needs to be updated",
    "author": "jane.smith",
    "created_at": "2024-11-07T14:20:00.000Z",
    "resolved": true
  },
  {
    "file": null,
    "line": null,
    "text": "Overall, this looks good to merge!",
    "author": "bob.wilson",
    "created_at": "2024-11-08T09:00:00.000Z",
    "resolved": false
  }
]

Development

Build

npm run build

Run

npm start

API Details

This server uses the GitLab REST API v4:

• Endpoint: /api/v4/projects/{project_id}/merge_requests/{merge_request_iid}/discussions
• Authentication: Personal Access Token via PRIVATE-TOKEN header

Debugging & Troubleshooting

Viewing Logs

All logs are written to stderr with the prefix [MCP]. When running in an MCP client, these logs will typically appear in the client's log file or console.

Example logs on startup:

[MCP] ====================================
[MCP] GitLab MR Comments MCP Server
[MCP] Version: 0.1.0
[MCP] ====================================
[MCP] Node version: v20.x.x
[MCP] Platform: linux
[MCP] CWD: /path/to/project
[MCP] Creating stdio transport...
[MCP] Connecting server to transport...
[MCP] ====================================
[MCP] Server successfully connected!
[MCP] Ready to receive tool calls
[MCP] ====================================

Example logs when tool is called:

[MCP] Tool called with args: {
  "project_id": "mygroup/myproject",
  "merge_request_iid": 123
}
[MCP] Starting fetchMergeRequestComments
[MCP] Resolving GitLab host from environment
[MCP] Resolved host: https://gitlab.com
[MCP] Resolving GitLab token from environment
[MCP] Token found (length: 20)
[MCP] SSL verification: enabled (default)
[MCP] Project ID: mygroup%2Fmyproject
[MCP] MR IID: 123
[MCP] Request URL: https://gitlab.com/api/v4/projects/mygroup%2Fmyproject/merge_requests/123/discussions
[MCP] Sending request to GitLab API...
[MCP] Response status: 200 OK
[MCP] Parsing response JSON...
[MCP] Received 5 discussions
[MCP] Include resolved: false
[MCP] Processed 12 comments
[MCP] Successfully fetched 12 comments

Common Issues

1. Environment Variables Not Set

Symptom:

[MCP] ERROR: GITLAB_HOST environment variable not set
[MCP] Available env vars: []

Solution: Make sure to set GITLAB_HOST and GITLAB_TOKEN in your MCP client configuration:

{
  "env": {
    "GITLAB_HOST": "https://gitlab.com",
    "GITLAB_TOKEN": "your-token-here"
  }
}

2. Authentication Error

Symptom:

[MCP] Response status: 401 Unauthorized
[MCP] Error response body: {"message":"401 Unauthorized"}

Solution:

• Check that your GitLab token is valid
• Ensure the token has api or read_api scope
• Verify you're using the correct token for your GitLab instance

3. Project Not Found

Symptom:

[MCP] Response status: 404 Not Found
[MCP] Error response body: {"message":"404 Project Not Found"}

Solution:

• Verify the project ID or path is correct
• Ensure you have access to the project
• For project paths with special characters, they will be automatically URL-encoded

4. SSL Certificate Issues

Symptom:

Error: self signed certificate in certificate chain

Solution: Disable SSL verification (for development/testing only):

{
  "env": {
    "GITLAB_SSL_VERIFY": "0"
  }
}

Testing Locally

Use the included test script to verify your configuration:

# Set environment variables
export GITLAB_HOST="https://gitlab.com"
export GITLAB_TOKEN="your-token-here"

# Run test
./test-mcp.sh

The server will start and show you all initialization logs. Press Ctrl+C to stop.

Checking MCP Client Logs

Different MCP clients store logs in different locations:

Claude Desktop (macOS):

tail -f ~/Library/Logs/Claude/mcp*.log

Claude Desktop (Linux):

tail -f ~/.config/Claude/logs/mcp*.log

Cline (VS Code):

• Check the VS Code Output panel
• Select "Cline" from the dropdown

License

MIT