PHP Package Scaffold (Composer / Packagist)

"A library is a contract. Once published, every breaking change is someone else's incident."

"Make it work, make it right, make it releasable."

Core Philosophy

This skill produces a publishable Composer library — not an application. The deliverable is a package that a stranger can composer require vendor/package, that installs cleanly across a matrix of supported PHP versions, that passes static analysis and style checks in CI, and that publishes to Packagist automatically on a semver git tag. Packagist serves whatever a tag points at, so the tag is the release — discipline lives in the tag and in CI, not in a manual upload step.

A library is a long-lived contract. Semantic versioning is mandatory: MAJOR.MINOR.PATCH, where a MAJOR bump is the only place a breaking change is allowed. The public API surface is everything not marked @internal; treat it as frozen within a major version.

Non-Negotiable Constraints:

1. Valid composer.json — composer validate --strict passes
2. PSR-4 autoloading — src/ mapped to a vendor namespace; tests in a separate autoload-dev
3. declare(strict_types=1) in every src/ file
4. Semver discipline — tags are vX.Y.Z; breaking changes only on MAJOR
5. CI gate before publish — tests + PHPStan + style must pass on the tag
6. Declared, bounded dependency constraints — caret ranges, no dev-master, no unbounded *

The full domain principles, AI discipline rules, anti-pattern catalog, and error-recovery procedures live in references/conventions.md.

Knowledge Base Lookups

Use search_knowledge (grounded-code-mcp, collection="php").

Workflow

Phase 1: PLAN

Decide the package identity and surface before writing files.

php -v | head -1
# Pick: vendor/name (lowercase, hyphenated), namespace (StudlyCase), license, PHP range
# Confirm the name is free on packagist.org

Record: vendor/package, root namespace, license (SPDX id), supported PHP range, runtime deps.

Phase 2: SCAFFOLD

See references/composer-json-template.md for the full manifest and references/ci-publish-workflow.md for the GitHub Actions and Packagist setup.

composer.json
src/                       # PSR-4 root; @internal on non-public classes
tests/                     # Pest or PHPUnit; autoload-dev
.github/workflows/ci.yml   # matrix: tests + phpstan + cs-fixer
phpstan.neon.dist          # level 8
.php-cs-fixer.dist.php      # PSR-12 ruleset
CHANGELOG.md               # Keep a Changelog
README.md  LICENSE  .gitignore  .gitattributes

Phase 3: VERIFY LOCALLY

composer validate --strict
composer install
vendor/bin/phpstan analyse src --level=8
vendor/bin/php-cs-fixer fix --dry-run --diff
vendor/bin/pest            # or vendor/bin/phpunit

Phase 4: PUBLISH

# After CI is green on main:
# 1. Update CHANGELOG.md with the new version
# 2. Tag with semver and push
git tag v1.0.0
git push origin v1.0.0
# Packagist auto-updates via the GitHub webhook (or `composer` API hook).

First-time only: submit the repo URL once at packagist.org and enable the GitHub service hook so future tags publish automatically.

State Block

<php-package-scaffold-state>
  phase: PLAN | SCAFFOLD | VERIFY | PUBLISH | COMPLETE
  package: vendor/name
  namespace: [root namespace]
  php_range: [e.g. ^8.2]
  license: [SPDX id]
  test_runner: pest | phpunit
  phpstan_level: [n]
  ci_created: true | false
  validate_passes: true | false
  packagist_registered: true | false
  last_action: [description]
</php-package-scaffold-state>

Output Template

Emit a ## PHP Package Scaffold: vendor/name report with Identity, Files Created, Gates, and Publish checklists. The full report markdown lives in references/conventions.md (Output Report Template).

Integration with Other Skills