GitHub Actions Expert

Skill para configurar GitHub Actions con detección proactiva de repos sin CI.

Proactive Detection

Al iniciar trabajo en un proyecto, verificar si existe .github/workflows/ :

ls -la .github/workflows/ 2>/dev/null || echo "NO_WORKFLOWS"

Si no hay workflows → preguntar al usuario si quiere agregar CI básico.

Workflow

Phase 0: Knowledge Update

Before generating any workflow, fetch latest documentation:

Search for latest GitHub Actions docs via Context7 or WebSearch:

• Current action versions (checkout, setup-node, setup-python, setup-go)

• Latest Node.js LTS version

• Recent best practices updates

Version Reference (verify these are current):

Action Current Version

actions/checkout v4

actions/setup-node v4

actions/setup-python v5

actions/setup-go v5

actions/cache v4

actions/upload-pages-artifact v3

actions/deploy-pages v4

Node.js LTS: Verify current LTS version (use WebSearch if unsure)

Phase 1: Stack Detection

Detect project type and tools:

Detect project type

ls package.json 2>/dev/null && echo "NODE_PROJECT" ls pyproject.toml requirements.txt 2>/dev/null && echo "PYTHON_PROJECT" ls go.mod 2>/dev/null && echo "GO_PROJECT"

For Node.js - detect package manager

ls pnpm-lock.yaml 2>/dev/null && echo "PNPM" ls bun.lockb 2>/dev/null && echo "BUN" ls package-lock.json 2>/dev/null && echo "NPM"

Detect Node version

cat .nvmrc 2>/dev/null || cat package.json | grep -A2 '"engines"'

Phase 2: Script Analysis (Node.js)

Read package.json using Read tool and detect available scripts.

Look for the scripts section and identify which scripts exist.

Common scripts to check:

• lint → Include linting step

• typecheck → Include type checking

• test → Include testing

• build → Include build step

• test:coverage → Include coverage upload

Phase 3: Workflow Selection

Present options based on detected stack:

For Node.js:

• CI Básico (lint, typecheck, test, build)

• Deploy a GitHub Pages

• Release con Tags (v*)

• Security Scans

• Coverage Upload (Codecov)

For Python:

• CI Básico (ruff, pyright/mypy, pytest)

• Coverage Upload

For Go:

• CI Básico (go vet, golangci-lint, go test)

• Release binaries

Phase 4: Generate Workflows

Load templates from references/ and customize:

Replace placeholders:

• {{NODE_VERSION}} → Detected or default (22.x)

• {{PACKAGE_MANAGER}} → npm/pnpm/bun

• {{INSTALL_COMMAND}} → npm ci / pnpm install --frozen-lockfile / bun install

• {{BRANCH}} → main/master (auto-detect)

• {{SCRIPTS}} → Based on available scripts

Always include:

• Concurrency control

• Caching for dependencies

• fail-fast strategy

Create .github/workflows/ if needed:

mkdir -p .github/workflows

Phase 5: Improve Existing Workflows

If workflows exist, analyze for anti-patterns:

cat .github/workflows/*.yml

Anti-patterns to detect:

Anti-Pattern Fix

actions/*@v3

Update to @v4

setup-node without cache Add cache: 'npm'

npm install

Use npm ci

No concurrency:

Add concurrency control

Matrix with single version Remove unnecessary matrix

Missing fail-fast: true

Add explicit fail-fast

See references/anti-patterns.md for full guide.

Phase 6: Verification

After generating:

Validate YAML (if actionlint available):

which actionlint && actionlint .github/workflows/*.yml

Check required permissions:

• GitHub Pages → pages: write , id-token: write

• Releases → contents: write

• PRs → pull-requests: write

Show summary:

Workflows Created/Updated

✓ .github/workflows/ci.yml

• Triggers: push (main), pull_request
• Jobs: lint, typecheck, test, build
• Node: 22.x with npm

Next Steps:

1. Review generated workflows
2. git add .github/workflows/
3. git commit -m "ci: add GitHub Actions workflow"
4. Push to trigger first run

Templates Reference

Templates are in references/ directory:

Template Description

nodejs-ci.yml

Standard CI with lint/typecheck/test/build

nodejs-deploy-pages.yml

Deploy to GitHub Pages

nodejs-release.yml

Release on tag push (v*)

python-ci.yml

Python CI with uv/pip, ruff, pytest

go-ci.yml

Go CI with vet, lint, test

security.yml

npm audit + secrets scanning

Best Practices Enforced

• Always use latest action versions (@v4 for most)

• Use npm ci over npm install for reproducible builds

• Enable caching in setup-node/setup-python/setup-go

• Add concurrency control to cancel outdated runs

• Use fail-fast: true to cancel parallel jobs on failure

• Specify permissions explicitly when needed

• Use Node 22.x (current LTS)

Concurrency Control Template

Always include in workflows:

concurrency: group: ${{ github.workflow }}-${{ github.ref }} cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}

This cancels outdated PR runs but never cancels main branch runs.

Package Manager Detection

Lockfile Package Manager Install Command

pnpm-lock.yaml

pnpm pnpm install --frozen-lockfile

bun.lockb

bun bun install --frozen-lockfile

package-lock.json

npm npm ci

None npm npm ci (after npm install generates lock)

Branch Detection

Detect default branch

git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's@^refs/remotes/origin/@@'

Or fallback

git branch -r | grep -E 'origin/(main|master)' | head -1 | sed 's@origin/@@'