Clean Code

Clean Code Reference

A comprehensive reference for writing clean, maintainable code based on Robert Martin's "Clean Code" and related works. This skill provides language-agnostic principles with examples that apply to any programming language.

When This Skill Activates

This skill automatically activates when you:

• Review code for quality or maintainability
• Need guidance on naming conventions
• Discuss refactoring or code smells
• Apply SOLID principles
• Improve code readability or structure
• Write or review unit tests

Quick Reference

SOLID Principles

| Principle | Summary | Violation Sign | |-----------|---------|----------------| | [Single Responsibility (SRP)](solid/single-responsibility.md) | One reason to change | Class does too many things | | [Open/Closed (OCP)](solid/open-closed.md) | Open for extension, closed for modification | Modifying existing code for new features | | [Liskov Substitution (LSP)](solid/liskov-substitution.md) | Subtypes must be substitutable | Subclass breaks parent behavior | | [Interface Segregation (ISP)](solid/interface-segregation.md) | No forced dependencies on unused methods | Fat interfaces | | [Dependency Inversion (DIP)](solid/dependency-inversion.md) | Depend on abstractions, not concretions | High-level modules import low-level |

Clean Code Practices

| Practice | Key Points | |----------|------------| | [Meaningful Names](practices/meaningful-names.md) | Intention-revealing, pronounceable, searchable | | [Functions](practices/functions.md) | Small, do one thing, one level of abstraction | | [Comments](practices/comments.md) | Code should be self-documenting; comments explain why, not what | | [Formatting](practices/formatting.md) | Consistent style, vertical density, horizontal alignment | | [Error Handling](practices/error-handling.md) | Exceptions over error codes, fail fast, don't return null | | [Unit Testing](practices/unit-testing.md) | F.I.R.S.T. principles, one assert per test, test behavior | | [Code Smells](practices/code-smells.md) | Recognition and refactoring of common problems | | [Boy Scout Rule](practices/boy-scout-rule.md) | Leave code cleaner than you found it |

The Boy Scout Rule

> "Leave the campground cleaner than you found it."

Every time you touch code, make it a little better. Small, incremental improvements compound over time.

Code Quality Checklist

Before committing code, verify:

• [ ] Names - Are all names intention-revealing?
• [ ] Functions - Is each function doing exactly one thing?
• [ ] Comments - Are comments explaining why, not what?
• [ ] DRY - Is there any duplicated logic?
• [ ] SOLID - Are principles being followed?
• [ ] Tests - Is the code tested and testable?
• [ ] Error Handling - Are errors handled gracefully?

Language Translation Notes

Examples use generic pseudocode. Adapt to your language:

• PHP: class, function, ->, type hints
• JavaScript/TypeScript: class, arrow functions, .
• Python: class, def, ., type hints
• Java/C#: Direct mapping with access modifiers

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Based on concepts from "Clean Code: A Handbook of Agile Software Craftsmanship" by Robert C. Martin, 2008.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: grndlvl
• Source: grndlvl/software-patterns
• License: MIT

Install and usage instructions live in the source repository linked above.