php-specialist

PHP Specialist

Overview

Write modern, type-safe, and maintainable PHP 8.x code adhering to PSR standards and SOLID principles. This skill covers the full modern PHP toolchain: language features introduced in PHP 8.0 through 8.4, PSR interoperability standards, Composer dependency management, static analysis with PHPStan and Psalm, coding style enforcement with PHP CS Fixer and Pint, and architectural patterns that leverage the type system for correctness at compile time rather than runtime.

Apply this skill whenever PHP code is being written, reviewed, or refactored in any framework or standalone context.

Multi-Phase Process

Phase 1: Environment Assessment

1. Identify PHP version from composer.json -> require.php
2. Review composer.json for autoloading strategy (PSR-4 namespaces)
3. Check for static analysis configuration (phpstan.neon, psalm.xml)
4. Identify coding standard tool (pint.json, .php-cs-fixer.php)
5. Catalog existing patterns: enums, DTOs, value objects, interfaces

STOP — Do NOT write code without knowing the PHP version and autoloading strategy.

Phase 2: Design

1. Define interfaces and contracts before implementations
2. Design value objects and DTOs with readonly properties
3. Map domain concepts to backed enums where applicable
4. Plan exception hierarchy for the domain
5. Identify seams for dependency injection

STOP — Do NOT implement without interfaces defined for key boundaries.

Phase 3: Implementation

1. Write interfaces first — contracts before concrete classes
2. Implement with constructor promotion, readonly properties, union/intersection types
3. Use match expressions over switch; named arguments for clarity
4. Leverage first-class callable syntax for functional composition
5. Apply SOLID principles at every class boundary

STOP — Do NOT skip strict_types declaration in any PHP file.

Phase 4: Quality Assurance

1. Run PHPStan at maximum achievable level (target level 9)
2. Enforce coding style with PHP CS Fixer or Laravel Pint
3. Verify type coverage — no mixed without justification
4. Review for SOLID violations and code smells
5. Confirm Composer autoload is optimized (--classmap-authoritative)