Coding

General Coding Best Practices

Overview

This skill provides a set of core principles and practices for software development. Use this when implementing new features, refactoring existing code, or reviewing code to ensure high quality and maintainability.

Core Principles

• DRY (Don't Repeat Yourself): Avoid logic duplication. If you find yourself writing the same code twice, abstract it.
• KISS (Keep It Simple, Stupid): Prefer simple, straightforward solutions over complex ones. Avoid over-engineering.
• YAGNI (You Ain't Gonna Need It): Don't implement features or abstractions until they are actually needed.
• SOLID Principles:
  • Single Responsibility: A class/function should have one reason to change.
  • Open/Closed: Software entities should be open for extension but closed for modification.
  • Liskov Substitution: Subtypes must be substitutable for their base types.
  • Interface Segregation: Many client-specific interfaces are better than one general-purpose interface.
  • Dependency Inversion: Depend on abstractions, not concretions.
• Existing Guidelines: - Follow existing guidelines in the project (e.g. CLAUDE.md, AGENT.md, etc.)

Implementation Guidelines

• Clean Code: Use descriptive names for variables, functions, and classes. Write code that is easy to read and understand.
• Small Functions: Keep functions small and focused on a single task.
• Error Handling: Use proactive error handling. Validate inputs and handle exceptions gracefully.
• Documentation: Document the why, not the what. Use self-documenting code where possible.
• Security: Sanitize inputs, avoid hardcoding secrets, and follow the principle of least privilege.
• Performance: Be mindful of time and space complexity, but avoid premature optimization.

Automated Analysis & Quality Control

• Static Analysis & Linting: Every project MUST have automated linting, formatting and static analysis (e.g., ESLint, Prettier, Ruff, Sonar).
  • Check: Identify if these tools are configured.
  • Propose: If missing, immediately propose adding them (e.g., npm install --save-dev eslint).
• Automated Tests: Ensure there is a test runner configured (e.g., Jest, Pytest).
  • Check: Look for tests/ directory or test configurations in package.json/pyproject.toml.
  • Propose: If missing, propose a testing framework and initial setup.

Verifying Code Changes

Before completing any task, you MUST perform the following verification loop:

1. Simplification: Use the code-simplifier plugin to make the code cleaner and more maintainable.
2. Self-Code Review:
   • Review the changes against the task requirements.
   • Ensure compliance with this coding skill (DRY, KISS, SOLID).
   • Check for potential security vulnerabilities or performance regressions.
3. Static Analysis & Linting:
   • If project does not have linting/formatting configured, propose adding it.
   • Run the project's linting/format commands (e.g., npm run lint, prettier --check .).
   • Fix all reported issues.
4. Unit Testing:
   • If project does not have a test runner configured, propose adding one.
   • Add Missing Tests: If new logic was added, write concise unit tests covering the happy path and edge cases.
   • Run Tests: Execute the test suite (e.g., npm test, pytest).
   • Verification: Ensure all tests pass. If they fail, fix the implementation or the test.

Key Principles

• Clarity over Cleverness: Write code for humans first, machines second.
• Consistency: Follow the established patterns and style of the existing codebase.
• Composition over Inheritance: Prefer combining simple objects to build complex ones rather than creating deep inheritance hierarchies.