USE when writing, debugging, or modifying GitHub Actions workflows (.github/workflows/*.yml), creating composite actions, reusable workflows, or workflow_call templates. USE for CI/CD pipeline configuration with GitHub Actions triggers, matrix strategies, caching, artifacts, secrets, OIDC, environment protection rules, or runner selection. USE when referencing actions/* marketplace actions, ${{ expressions }}, or GITHUB_TOKEN permissions. DO NOT USE for Dagger CI, GitLab CI, CircleCI, Jenkins, Travis CI, or other non-GitHub CI/CD systems. DO NOT USE for general YAML editing unrelated to GitHub Actions.
Place workflow files in .github/workflows/ with .yml or .yaml extension. Every workflow requires name, on (trigger), and jobs.