AI PR Description Generator

Automatically generates detailed PR descriptions from your diffs using Claude AI. No more empty PR descriptions.

Quick Start

# .github/workflows/pr-description.yml
name: AI PR Description
on:
  pull_request:
    types: [opened]

permissions:
  contents: read
  pull-requests: write

jobs:
  describe:
    runs-on: ubuntu-latest
    steps:
      - uses: avatrix1/ai-pr-description@v1
        with:
          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}

What It Does

When a PR is opened without a description (or with less than 100 characters), this action:

1. Reads the diff and file changes
2. Sends them to Claude AI
3. Updates the PR with a structured description containing:
   • Summary — what the PR does and why
   • Changes — key changes grouped by area
   • Testing — how to verify the changes

If the PR already has a description longer than 100 characters, the action skips to avoid overwriting manually written descriptions.

Inputs

Input	Description	Required	Default
anthropic_api_key	Your Anthropic API key	Yes	—
github_token	GitHub token for updating the PR	No	${{ github.token }}
model	Claude model to use	No	claude-sonnet-4-20250514
max_diff_size	Max diff size in chars sent to Claude	No	50000

Example Output

## Summary
Adds rate limiting to the API endpoint to prevent abuse. Implements a per-key
counter with configurable limits and proper HTTP 429 responses.

## Changes
- Add in-memory usage tracking per API key
- Return X-RateLimit headers on all responses
- Add 429 response when limit exceeded

## Testing
Send repeated requests to the API endpoint and verify the rate limit headers
decrement correctly. After hitting the limit, confirm a 429 response is returned.

License

MIT