quality-engineering

Overview

Domain specialist for code quality assessment, maintainability, complexity analysis, code smells detection, anti-patterns identification, and code style enforcement. Expertise includes code review methodologies, naming conventions, coding standards, and technical debt management.

Trigger Words

• quality, code quality, code health
• smell, code smell, anti-pattern
• complexity, cyclomatic complexity
• maintainability, maintainable code
• naming, naming convention
• style, code style, linting
• technical debt, debt, code debt
• refactoring, refactor
• review, code review
• clean code, clean code principles
• SOLID principles

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Detection

Code Quality Tools

JavaScript/TypeScript:

• ESLint (eslint, eslint.config.js)
• Prettier (.prettierrc)
• TypeScript (tsconfig.json)
• SonarQube (sonar-project.properties)

Python:

• Flake8 (.flake8, setup.cfg, tox.ini)
• Black (pyproject.toml, .black)
• Ruff (ruff.toml, .ruff.toml)
• mypy (mypy.ini)
• Pylint (.pylintrc)

PHP:

• PHPStan (phpstan.neon, phpstan-dist.neon)
• Psalm (psalm.xml)
• PHP_CodeSniffer (phpcs.xml, ruleset.xml)
• PHP-CS-Fixer (.php-cs-fixer.php)

Ruby:

• RuboCop (.rubocop.yml)
• RuboCop Performance (rubocop-performance.yml)

Go:

• golint, staticcheck, golangci-lint (.golangci.yml)

Java:

• Checkstyle (checkstyle.xml)
• PMD, SpotBugs (pmd.xml)
• SonarQube

C#:

• StyleCop, ReSharper (*.ruleset)

Code Complexity Tools

• Cyclomatic Complexity: complexity-report
• Maintainability Index: mi
• Code Duplication: jscpd, phpcpd

Technical Debt Tracking

• SonarQube (technical debt metrics)
• CodeClimate (quality metrics)
• Lighthouse (web performance)

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Mode Detection

Write Mode (Progressive Guidance)

Trigger: mode=write or no explicit quality task

Load Progressive Files:

1. CODE-STYLE.md - Coding standards and conventions
2. NAMING-CONVENTIONS.md - Consistent naming
3. COMPLEXITY.md - Complexity analysis and reduction

Behavior:

• Provide concise examples
• Focus on applying standards
• Progressive complexity (simple → advanced)
• Framework-specific guidance

Review Mode (Exhaustive Checklists)

Trigger: mode=review, "review code", "assess quality", "check code health", "audit code", "code quality assessment"

Load Review Files:

1. CODE-SMELLS.md - Comprehensive code smell detection
2. ANTI-PATTERNS.md - Anti-pattern identification
3. CODE-HEALTH.md - Health assessment checklist
4. MAINTAINABILITY.md - Maintainability evaluation

Behavior:

• Exhaustive review checklists
• Identify code smells and anti-patterns
• Assess complexity metrics
• Evaluate maintainability
• Gap identification and prioritization

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Skill Loading Strategy

Initial Load

function loadQualityEngineeringSkill(context) {
    const mode = context.mode || 'write';

    if (mode === 'review') {
        // Load review-mode files
        loadProgressive([
            'CODE-SMELLS.md',
            'ANTI-PATTERNS.md',
            'CODE-HEALTH.md',
            'MAINTAINABILITY.md'
        ]);
    } else {
        // Load write-mode files
        loadProgressive([
            'CODE-STYLE.md',
            'NAMING-CONVENTIONS.md',
            'COMPLEXITY.md'
        ]);
    }

    // Always load core concepts based on query keywords
    if (context.query.match(/smell|anti-pattern/)) {
        loadProgressive(['CODE-SMELLS.md', 'ANTI-PATTERNS.md']);
    }

    if (context.query.match(/complexity|cyclomatic/)) {
        load('COMPLEXITY.md');
    }

    if (context.query.match(/maintain|maintainable/)) {
        load('MAINTAINABILITY.md');
    }

    if (context.query.match(/naming|convention/)) {
        load('NAMING-CONVENTIONS.md');
    }

    if (context.query.match(/style|lint|formatting/)) {
        load('CODE-STYLE.md');
    }

    if (context.query.match(/health|review|audit/)) {
        loadProgressive([
            'CODE-SMELLS.md',
            'ANTI-PATTERNS.md',
            'CODE-HEALTH.md'
        ]);
    }

    if (context.query.match(/debt|refactor/)) {
        loadProgressive([
            'COMPLEXITY.md',
            'CODE-SMELLS.md',
            'ANTI-PATTERNS.md'
        ]);
    }
}

---

Progressive Disclosure Files

Assessment (Progressive)

1. CODE-SMELLS.md - Code smell detection (duplicate code, long methods, etc.)
2. ANTI-PATTERNS.md - Anti-patterns (God Object, Magic Numbers, etc.)
3. CODE-HEALTH.md - Health assessment checklist
4. COMPLEXITY.md - Complexity analysis (cyclomatic, cognitive, maintainability index)
5. MAINTAINABILITY.md - Maintainability evaluation

Standards (Progressive)

6. NAMING-CONVENTIONS.md - Consistent naming across languages
7. CODE-STYLE.md - Coding standards and linting

---

Quick Reference

Code Quality Metrics

Metric	Good	Excellent	Target
Cyclomatic Complexity	<10	<5	<10 per function
Maintainability Index	>20	>85	>20 (MI = 171 - 5.2 × ln(CC) - 0.23 × CC - 16.2 × ln(LOC))
Code Duplication	<5%	<3%	<5% duplicated
Code Smells	<10	<5	Smells per 1000 LOC
Test Coverage	70%	90%	See testing-engineering
Technical Debt Ratio	<5%	<2%	Debt / Total Code

Code Quality Dimensions

Dimension	Metrics	Tools
Readability	Naming, formatting, comments	Linters, formatters
Complexity	Cyclomatic, cognitive, nesting	Complexity analyzers
Maintainability	MI, duplication, coupling	SonarQube, CodeClimate
Reliability	Test coverage, bug density	Test frameworks, issue trackers
Performance	Execution time, memory usage	Profilers, benchmarking
Security	Vulnerabilities, dependency issues	SAST, dependency scanners

Common Code Quality Tools

Language	Linter	Formatter	Complexity	Coverage
JavaScript	ESLint	Prettier	ESLint complexity	Jest/Istanbul
TypeScript	ESLint + TSLint	Prettier	TSLint	Jest/Istanbul
Python	Flake8, Ruff	Black	Radon	PyTest/Coverage.py
PHP	PHPStan	PHP-CS-Fixer	PHPStan	PHPUnit
Ruby	RuboCop	RuboCop	RuboCop	SimpleCov
Go	golint	gofmt	gocyclo	go test -cover
Java	Checkstyle, PMD	SpotBugs	PMD	JaCoCo
C#	StyleCop	dotnet format	ReSharper	dotCover

---

Core Concepts

SOLID Principles

1. S - Single Responsibility Principle: Each class should have one reason to change
2. O - Open/Closed Principle: Open for extension, closed for modification
3. L - Liskov Substitution Principle: Subtypes must be substitutable for base types
4. I - Interface Segregation Principle: Many specific interfaces > one general interface
5. D - Dependency Inversion Principle: Depend on abstractions, not concretions

Code Smell Categories

• Bloaters: Long methods, large classes, primitive obsession
• Object-Orientation Abusers: Switch statements, alternative classes
• Change Preventers: Divergent change, parallel inheritance, shotgun surgery
• Dispensables: Comments, dead code, unnecessary abstractions
• Couplers: Feature envy, inappropriate intimacy, data clumps
• Coupling: Law of Demeter, inappropriate intimacy
• Deodorants: Message chains, middle man, inappropriate intimacy

Anti-Patterns

• Creational: Singleton, Factory, Builder, Prototype
• Structural: Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy
• Behavioral: Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor
• Architectural: Front Controller, Model-View-Controller (MVC), Service Locator

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When to Use This Skill

Use When:

• User mentions quality, code quality, code health
• Reviewing code for smells or anti-patterns
• Assessing complexity or maintainability
• Establishing coding standards or conventions
• Technical debt assessment
• Code review preparation
• Refactoring guidance
• Setting up linting/formatting tools

Do Not Use For:

• Implementation details of specific libraries/frameworks (use framework-specific skills)
• Database queries (use database-engineering)
• Security vulnerabilities (use secops-engineering)
• Performance optimization (use performance-engineering)
• Testing strategies (use testing-engineering)

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Internal References

This skill does NOT reference other skills. All quality concepts are self-contained.

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File Structure

~/.config/opencode/skill/quality-engineering/
├── SKILL.md (this file)
├── assessment/
│   ├── CODE-SMELLS.md
│   ├── ANTI-PATTERNS.md
│   ├── CODE-HEALTH.md
│   ├── COMPLEXITY.md
│   └── MAINTAINABILITY.md
└── standards/
    ├── NAMING-CONVENTIONS.md
    └── CODE-STYLE.md