pantheon-ai/github-actions-validator

Comprehensive toolkit for validating, linting, and testing GitHub Actions workflow files, custom local actions, and public actions. Use this skill when working with GitHub Actions YAML files (.github/workflows/*.yml), validating workflow syntax, testing workflow execution with act, or debugging workflow issues.

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Modern GitHub Actions Features Reference

Name: pantheon-ai/github-actions-validator
Rating: 0.93 (1 reviews)
Author: pantheon-ai

This reference covers validation of modern GitHub Actions features including reusable workflows, attestations, OIDC authentication, and more.

Reusable Workflows

Validation Points

workflow_call trigger configuration
Required and optional inputs with correct types
Secrets declaration and usage
Outputs definition

Example

# Reusable workflow (.github/workflows/reusable-deploy.yml)
on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string
      deploy-version:
        required: false
        type: string
        default: 'latest'
    secrets:
      deploy-token:
        required: true
    outputs:
      deployment-url:
        description: "The URL of the deployment"
        value: ${{ jobs.deploy.outputs.url }}

jobs:
  deploy:
    runs-on: ubuntu-latest
    outputs:
      url: ${{ steps.deploy.outputs.url }}
    steps:
      - name: Deploy
        id: deploy
        run: echo "url=https://example.com" >> $GITHUB_OUTPUT

Common Errors

Incorrect input types (string, number, boolean)
Missing required secrets
Invalid output references

Workflow Limits (November 2025)

GitHub Actions increased reusable workflow limits:

Nested workflows: Up to 10 levels (previously 4)
Total workflows per run: Up to 50 workflows (previously 20)

This enables complex workflow compositions and better code reuse.

SBOM and Build Provenance Attestations

Validation Points

Correct permissions (id-token: write, attestations: write)
Valid artifact paths
Proper attestation action usage

Example

permissions:
  id-token: write
  contents: read
  attestations: write

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6

      - name: Build artifact
        run: |
          mkdir -p dist
          tar -czvf dist/app.tar.gz ./src

      - name: Generate SBOM
        run: |
          # Generate SPDX SBOM
          syft ./src -o spdx-json > sbom.spdx.json

      - uses: actions/attest-sbom@v3
        with:
          subject-path: '${{ github.workspace }}/dist/*.tar.gz'
          sbom-path: '${{ github.workspace }}/sbom.spdx.json'

      - uses: actions/attest-build-provenance@v3
        with:
          subject-path: '${{ github.workspace }}/dist/*.tar.gz'

Common Errors

Missing required permissions
Invalid subject-path glob patterns
Incorrect SBOM format

OIDC Authentication

Validation Points

Correct permissions (id-token: write)
Valid audience claims
Proper OIDC provider configuration
Token claim validation in receiving systems

Available Token Claims (November 2025)

Claim	Description
`repository`	Repository name
`ref`	Git ref (branch/tag)
`sha`	Commit SHA
`workflow`	Workflow name
`run_id`	Workflow run ID
`run_attempt`	Attempt number
`check_run_id`	NEW - Specific check run ID for the job
`actor`	User who triggered the workflow
`environment`	Deployment environment (if applicable)

Example: AWS OIDC

permissions:
  id-token: write
  contents: read

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - name: Configure AWS Credentials
        uses: aws-actions/configure-aws-credentials@v4
        with:
          role-to-assume: arn:aws:iam::123456789012:role/GitHubActionsRole
          aws-region: us-east-1
          # Token now includes check_run_id for granular tracking

      - name: Deploy to AWS
        run: aws s3 sync ./build s3://my-bucket/

AWS IAM Policy with check_run_id

{
  "Version": "2012-10-17",
  "Statement": [{
    "Effect": "Allow",
    "Principal": {
      "Federated": "arn:aws:iam::123456789012:oidc-provider/token.actions.githubusercontent.com"
    },
    "Action": "sts:AssumeRoleWithWebIdentity",
    "Condition": {
      "StringEquals": {
        "token.actions.githubusercontent.com:sub": "repo:org/repo:ref:refs/heads/main",
        "token.actions.githubusercontent.com:aud": "sts.amazonaws.com"
      },
      "StringLike": {
        "token.actions.githubusercontent.com:check_run_id": "*"
      }
    }
  }]
}

Benefits of check_run_id

Fine-grained access control: Trace tokens to exact job and compute
Improved auditability: Track which specific check run made API calls
Least-privilege policies: Attribute-based access control without enumerating repositories
Faster revocation: Reduce secret exposure risk

Deployment Environments

Validation Points

Environment name configuration
Protection rules compatibility
Required reviewers setup
Environment variables and secrets scope

Example

jobs:
  deploy-staging:
    runs-on: ubuntu-latest
    environment:
      name: staging
      url: https://staging.example.com
    steps:
      - uses: actions/checkout@v6
      - run: ./deploy.sh staging

  deploy-production:
    runs-on: ubuntu-latest
    needs: deploy-staging
    environment:
      name: production
      url: https://prod.example.com
    steps:
      - uses: actions/checkout@v6
      - run: ./deploy.sh production

Common Errors

Undefined environment names
Missing URL for environment tracking
Incorrect environment variable scope

Job Summaries

Validation Points

Correct usage of $GITHUB_STEP_SUMMARY
Valid Markdown formatting
Proper escaping of dynamic content

Example

steps:
  - name: Run tests
    id: tests
    run: |
      # Run tests and capture results
      npm test 2>&1 | tee test-output.txt
      PASSED=$(grep -c "PASS" test-output.txt || echo 0)
      FAILED=$(grep -c "FAIL" test-output.txt || echo 0)
      echo "passed=$PASSED" >> $GITHUB_OUTPUT
      echo "failed=$FAILED" >> $GITHUB_OUTPUT

  - name: Generate summary
    run: |
      echo "## Test Results" >> $GITHUB_STEP_SUMMARY
      echo "" >> $GITHUB_STEP_SUMMARY
      echo "| Status | Count |" >> $GITHUB_STEP_SUMMARY
      echo "|--------|-------|" >> $GITHUB_STEP_SUMMARY
      echo "| Passed | ${{ steps.tests.outputs.passed }} |" >> $GITHUB_STEP_SUMMARY
      echo "| Failed | ${{ steps.tests.outputs.failed }} |" >> $GITHUB_STEP_SUMMARY

Note: Job summaries are runtime features - actionlint validates script syntax but not summary content.

Container Jobs

Validation Points

Valid container image references
Correct volume mounts
Environment variable configuration
Service container networking

Example

jobs:
  test:
    runs-on: ubuntu-latest
    container:
      image: node:24
      env:
        NODE_ENV: test
      volumes:
        - /data:/data

    services:
      postgres:
        image: postgres:16
        env:
          POSTGRES_PASSWORD: postgres
          POSTGRES_DB: testdb
        ports:
          - 5432:5432
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5

      redis:
        image: redis:7
        ports:
          - 6379:6379

    steps:
      - uses: actions/checkout@v6

      - name: Install dependencies
        run: npm ci

      - name: Run tests
        env:
          DATABASE_URL: postgres://postgres:postgres@postgres:5432/testdb
          REDIS_URL: redis://redis:6379
        run: npm test

Common Errors

Invalid image tags
Incorrect volume mount syntax
Service container networking issues
Missing health checks for services

Matrix Strategies

Validation Points

Matrix values must be arrays
Valid matrix variable references
Proper include/exclude syntax

Example

jobs:
  test:
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu-latest, windows-latest, macos-latest]
        node: [20, 22, 24]
        exclude:
          - os: macos-latest
            node: 20
        include:
          - os: ubuntu-latest
            node: 24
            experimental: true

    steps:
      - uses: actions/checkout@v6
      - uses: actions/setup-node@v6
        with:
          node-version: ${{ matrix.node }}
      - run: npm test

Concurrency Control

Validation Points

Valid concurrency group names
Proper cancel-in-progress usage

Example

name: CI

on:
  push:
    branches: [main]
  pull_request:

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

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
      - run: npm ci && npm run build

This prevents redundant runs while protecting main branch runs from cancellation.

Install with Tessl CLI

npx tessl i pantheon-ai/github-actions-validator@0.1.1

assets

references

scripts

pantheon-ai/github-actions-validator

modern_features.md.css-3qkkll{font-size:var(--chakra-font-sizes-sm);font-weight:var(--chakra-font-weights-normal);color:var(--chakra-colors-gray-300);}references/

Modern GitHub Actions Features Reference

Reusable Workflows

Validation Points

Example

Common Errors

Workflow Limits (November 2025)

SBOM and Build Provenance Attestations

Validation Points

Example

Common Errors

OIDC Authentication

Validation Points

Available Token Claims (November 2025)

Example: AWS OIDC

AWS IAM Policy with check_run_id

Benefits of check_run_id

Deployment Environments

Validation Points

Example

Common Errors

Job Summaries

Validation Points

Example

Container Jobs

Validation Points

Example

Common Errors

Matrix Strategies

Validation Points

Example

Concurrency Control

Validation Points

Example

modern_features.mdreferences/