the-pr-agent/pr-agent ? reverse-engineered prompt

Build me an open source AI PR reviewer called PR Agent.

I want it to work as a GitHub Action and also from the command line, so I can point it at a pull request and have it leave useful review comments automatically. It should support the common actions people use on PRs, like describing what changed, reviewing the code, suggesting improvements, and answering questions about the PR. It should feel easy to set up with a simple config file and environment variables for the model key and GitHub token.

Please make it work with more than one AI provider if possible, and keep it flexible enough that teams can customize the review behavior. Use the repo docs as the source of truth, and if you need current setup details from the model or GitHub Action side, look them up online. I care most about a smooth first run, clear comments on the PR, and a clean local dev experience.