🤖 ChatGPT Code Review Bot

This repo demonstrates how to use OpenAI's ChatGPT to automatically review pull requests in a GitHub repository. It leverages GitHub Actions, the OpenAI API, and a TypeScript script to analyze code changes and post a summary directly to the PR.

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📁 Project Structure

.
├── code
│ └── example.ts                    # Sample TypeScript function (used to test the review)
├── scripts
│   └── code-review
│       ├── index.ts          # The main TypeScript review script
│       ├── package.json      # Local dependencies for the review script
│       ├── tsconfig.json     # TypeScript config
│       └── yarn.lock
└── workflows
└── chatgpt-review.yml              # GitHub Actions workflow that runs the review

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🚀 How It Works

Whenever a pull request is opened or updated:

1. GitHub Actions triggers the chatgpt-review.yml workflow.
2. The action checks out the code and runs a TypeScript script using ts-node.
3. The script:
   • Fetches the code diffs in the PR
   • Sends them to OpenAI’s ChatGPT API with a review prompt
   • Posts the review summary as a comment on the pull request

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🛠 Setup Instructions

1. Clone the repository and install dependencies

cd .github/scripts/code-review
yarn install

2. Add required secrets to your GitHub repository

Go to your repo → Settings → Secrets and variables → Actions → New repository secret

• OPENAI_API_KEY — your OpenAI API key
• GITHUB_TOKEN — default GitHub token (already available in Actions, but required in the script)

Note: The default GITHUB_TOKEN will work only for internal PRs. For forked PRs, you'll need to use a GitHub App or bot account.

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3. Confirm workflow is enabled

The file .github/workflows/chatgpt-review.yml should already exist. It’s triggered automatically on:

on:
  pull_request:
    types: [opened, synchronize]

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✏️ Example Usage

You can edit code/example.ts and open a pull request. The ChatGPT bot will analyze the code and leave a comment on the PR with suggestions, improvements, or warnings.

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⚠️ Permissions Note

To allow the GitHub Action to post comments, the workflow must request permissions:

permissions:
  contents: read
  pull-requests: write

This is already included in the chatgpt-review.yml.

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🧠 Customizing the Prompt

Want a stricter review? Friendlier tone? Edit the prompt in:

// .github/scripts/code-review/index.ts
const prompt = `
You're a senior software engineer reviewing a code diff.

Please:
- Spot logic or syntax errors
- Identify any risky or suspicious changes
- Recommend improvements
- Be concise but helpful

Code diff:
${codeDiffs}
`;

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🧪 Local Testing

You can test the review script locally (without GitHub) like this:

cd .github/scripts/code-review
OPENAI_API_KEY=your_key_here GITHUB_TOKEN=your_token_here yarn review

You’ll need to mock github.context or pass in data for local testing.

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✅ To Do

• Support forked PRs with GitHub App
• Add inline comments instead of summary
• Limit file types (e.g. only .ts or .js)
• Improve prompt templates

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📄 License

MIT (add it in package.json too if you want to avoid warnings)