How to Automate Code Reviews with AI GitHub Actions

Code reviews are a bottleneck. Your senior dev is in meetings all day, PRs pile up, and junior devs wait. What if every PR got instant feedback the moment it was opened? You can set that up in 15 minutes with GitHub Actions and AI. What We're Building A GitHub Action that triggers on every pull request, reads the diff, sends it to an AI model, and posts a review comment with suggestions, bugs, and improvements. Step 1: Create the Workflow File Create .github/workflows/ai-review.yml in your repo: name : AI Code Review on : pull_request : types : [ opened , synchronize ] permissions : contents : read pull-requests : write jobs : review : runs-on : ubuntu-latest steps : - uses : actions/checkout@v4 with : fetch-depth : 0 - name : Get PR diff id : diff run : | git diff origin/${{ github.base_ref }}...HEAD > diff.txt echo "diff_size=$(wc -c < diff.txt)" >> $GITHUB_OUTPUT - name : AI Review if : steps.diff.outputs.diff_size > 0 env : ANTHROPIC_API_KEY : ${{ secrets.ANTHROPIC_API_KEY }} run :