quality-engineering Skill

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

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)

Mode Detection

Write Mode (Progressive Guidance)

Trigger: mode=write or no explicit quality task

Load Progressive Files:

CODE-STYLE.md - Coding standards and conventions
NAMING-CONVENTIONS.md - Consistent naming
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:

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

Behavior:

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

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)

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

Standards (Progressive)

NAMING-CONVENTIONS.md - Consistent naming across languages
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

S - Single Responsibility Principle: Each class should have one reason to change
O - Open/Closed Principle: Open for extension, closed for modification
L - Liskov Substitution Principle: Subtypes must be substitutable for base types
I - Interface Segregation Principle: Many specific interfaces > one general interface
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

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)

Internal References

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

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

Agent Skills: quality-engineering

Install this agent skill to your local

Skill Files