github-actions-nx

When to Use

Use this skill when:

• Creating or modifying any file under .github/workflows/
• Adding a new Nx project that needs CI (service, library, docs)
• Adding a pipeline for files that need rendering/compilation (LaTeX, Mermaid, Protobuf, etc.)
• Reviewing or optimizing CI execution time

Core Principles

1. Nx drives project detection — Use nrwl/nx-set-shas + nx show projects --affected to know WHICH projects changed. Never hardcode path checks with git diff alone.
2. Only run what changed — Every job MUST have an if: condition gated on the affected project output.
3. Only render what changed — For renderable artifacts (LaTeX, Mermaid, Protobuf, etc.), use git diff to detect the specific FILES that changed, then compile/render only those files via a matrix strategy.
4. Parallel by default — Independent projects run in parallel. Use needs: only for real dependencies (e.g., bundle depends on compile).
5. Fail fast is off for artifacts — Use fail-fast: false in matrix strategies so one broken file doesn't block others.