ChatGPT GitHub PR Reviewer

A ChatGPT app that helps you review GitHub Pull Requests directly from within ChatGPT conversations. Built using OpenAI's Apps SDK with the Model Context Protocol (MCP).

Features

• Connect GitHub - OAuth login to connect your GitHub account

• List Pull Requests - View PRs you authored, need to review, or are involved in

• Get PR Context - Full PR details including files changed, diffs, and metadata

• Post Comments - Add general comments or inline comments on specific files/lines

• Approve PRs - Approve pull requests with optional comment

• Request Changes - Request changes with feedback

• Idempotency Protection - Prevents duplicate comments on retries

• OAuth 2.1 Compliant - Full MCP authorization spec with PKCE and discovery endpoints

Related MCP server: GitHub Code Review Assistant

MCP Tools

1. check_github_auth_status

Connect and check GitHub authentication status.

Input: None

Output (not authenticated):

{
  "authenticated": false,
  "authUrl": "https://github.com/login/oauth/authorize?..."
}

Output (authenticated):

{
  "authenticated": true,
  "user": { "login": "username", "name": "Full Name" }
}

2. list_pull_requests

List pull requests with priority cascade.

Input:

{
  "username": "octocat"  // Optional: filter by author
}

Default behavior (no username):

1. First shows PRs where YOU are the author

2. If none, shows PRs where you are a reviewer

3. If none, shows PRs where you are involved

Output:

{
  "pullRequests": [...],
  "searchType": "authored" | "reviewing" | "involved" | "user_authored",
  "totalCount": 5
}

3. get_pr_context

Get full context for a PR including files changed and diffs.

Input:

{
  "pr_name": "owner/repo#123"
}

Output:

{
  "pr": { "number": 123, "title": "...", "author": "..." },
  "description": "PR description...",
  "files": [
    { "filename": "src/index.ts", "status": "modified", "additions": 10, "deletions": 5, "patch": "..." }
  ],
  "commits": 3,
  "additions": 50,
  "deletions": 20
}

4. post_review_comments

Post review comments to a PR. Supports general and inline comments.

Input:

{
  "pr_name": "owner/repo#123",
  "comments": [
    { "body": "Looks good!" },
    { "body": "Use async here", "path": "src/index.ts", "line": 42 }
  ],
  "event": "COMMENT" | "APPROVE" | "REQUEST_CHANGES",
  "idempotency_key": "unique-key-123"
}

Comment Types:

• General comment: Only body - appears in PR conversation

• Inline comment: body + path + line - appears on specific line

Output:

{
  "success": true,
  "reviewId": 12345,
  "prUrl": "https://github.com/owner/repo/pull/123",
  "commentsPosted": 2
}

Example Prompts

1. Connect GitHub

2. List Pull Requests

3. Get PR Context

4. Post Review Comments

Project Structure

chatgpt-github-pr-reviewer/
├── package.json                 # Root package with npm workspaces
├── server/
│   └── src/
│       ├── index.ts             # Express server with OAuth endpoints
│       ├── mcp-server.ts        # MCP protocol handler
│       ├── mcp-oauth.ts         # OAuth 2.1 implementation
│       ├── github-auth.ts       # GitHub OAuth logic
│       ├── github-api.ts        # GitHub API integration
│       ├── idempotency-service.ts # Duplicate prevention
│       ├── token-store.ts       # GitHub token storage
│       └── types.ts             # TypeScript types
└── widget/
    └── src/
        ├── GitHubWidget.tsx     # Main widget component
        └── components/          # UI components

Environment Variables

# GitHub OAuth (from GitHub Developer Settings)
GITHUB_CLIENT_ID=your_github_client_id
GITHUB_CLIENT_SECRET=your_github_client_secret
GITHUB_REDIRECT_URI=http://localhost:3000/github/callback

# Server
PORT=3000
NODE_ENV=development

# MCP OAuth (for ChatGPT authentication)
MCP_OAUTH_CLIENT_ID=chatgpt-mcp-client
MCP_OAUTH_CLIENT_SECRET=chatgpt-mcp-secret-key-2024

# Widget Base URL
WIDGET_BASE_URL=https://your-app.railway.app

GitHub OAuth App Setup

Step 1: Create GitHub OAuth App

1. Go to GitHub Developer Settings

2. Click "OAuth Apps" → "New OAuth App"

3. Fill in:

   • Application name: ChatGPT PR Reviewer

   • Homepage URL: https://your-app.railway.app

   • Authorization callback URL: https://your-app.railway.app/github/callback

4. Copy Client ID and Client Secret to .env

Step 2: Required Scopes

Local Development

# Install dependencies
npm install

# Create .env file
cp .env.example .env
# Edit .env with your GitHub OAuth credentials

# Start development server
npm run dev

Deployment

Railway

1. Connect your GitHub repo to Railway

2. Add environment variables:

   GITHUB_CLIENT_ID=your_client_id
   GITHUB_CLIENT_SECRET=your_client_secret
   GITHUB_REDIRECT_URI=https://your-app.railway.app/github/callback
   PORT=3000
   NODE_ENV=production
   WIDGET_BASE_URL=https://your-app.railway.app

ChatGPT Integration

1. Create a new ChatGPT App

2. Configure MCP:

   • Discovery URL: https://your-app.railway.app/.well-known/oauth-authorization-server

3. Test with: "Connect my GitHub" or "List my PRs"

Credits

Built with:

• OpenAI Apps SDK

• Model Context Protocol (MCP)

• GitHub REST API

• React

• Vite

Happy PR Reviewing!