A code review bot is an AI tool that reads a pull request and leaves comments pointing out bugs, risks and possible fixes before a person merges it.
In plain words
When someone opens a pull request, the bot reads the changes, sometimes gathering context from the rest of the repository, and posts a summary plus comments on specific lines. Open-source PR-Agent runs from commands typed as PR comments, such as asking it to describe, review or suggest improvements. GitHub's own docs warn that an AI reviewer will miss some issues and make mistakes, so a human review is still needed.
A quick example
A developer opens a pull request and types /review in a comment. PR-Agent replies with a review of the change, and /improve returns suggested code edits the author can accept or ignore.
Where you'll meet it
- Pull request checks on GitHub, GitLab and Bitbucket.
- Catching simple issues before a teammate reviews.
Related
Sources
- Docspr-agent, PR-Agent (GitHub) · read 10 Nov 2026
- DocsAbout GitHub Copilot code review, GitHub Docs · read 29 Sept 2026
Checked by WhatIsAI against the sources above · 11 Nov 2026. Spotted an error? Report it.