Agent-Skills.md

Agent Skills: Fundamental Coding Principles

Fundamental coding principles (DRY, KISS, YAGNI, SOLID, HHH). Use when starting any development task, evaluating implementation approaches, or reviewing code quality. Always active as foundation for all development decisions.

UncategorizedID: tianjianjiang/smith/smith-principles

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tianjianjiang/smith
tianjianjiang

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pnpm dlx add-skill https://github.com/tianjianjiang/smith/tree/HEAD/smith-principles

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smith-principles/SKILL.md

Skill Metadata

Name
smith-principles
Description
Fundamental coding principles (DRY, KISS, YAGNI, SOLID, HHH). Use when starting any development task, evaluating implementation approaches, or reviewing code quality. Always active as foundation for all development decisions.

Fundamental Coding Principles

Load if: Always active (foundation for all development) Prerequisites: None

Critical Rules

  • MUST apply DRY before adding features
  • MUST apply KISS to choose simplest solution
  • MUST apply YAGNI to defer unneeded implementation
  • Keep one reason to change per class/module (Single Responsibility)
  • Depend on abstractions, not concretions, to avoid tight coupling
  • Abstract code that would otherwise be duplicated

Core Principles

  • DRY (Don't Repeat Yourself): Single source of truth
  • KISS (Keep It Simple, Stupid): Simplest solution that works
  • YAGNI (You Aren't Gonna Need It): Don't implement until needed
  • SINE (Simple Is Not Easy): Simplicity requires deliberate effort
  • MECE (Mutually Exclusive, Collectively Exhaustive): Complete coverage without overlap
  • Occam's Razor: Prefer solutions with fewest assumptions

SOLID Principles

  • S (Single Responsibility): One reason to change per class/module
  • O (Open/Closed): Open for extension, closed for modification
  • L (Liskov Substitution): Subtypes substitutable for base types
  • I (Interface Segregation): Many specific interfaces over one general
  • D (Dependency Inversion): Depend on abstractions, not concretions

HHH (AI Behavior)

  • H (Helpful): Provide useful, actionable assistance
  • H (Honest): Be truthful, acknowledge uncertainty
  • H (Harmless): Avoid destructive operations without confirmation

Related

  • @smith-standards/SKILL.md - Universal coding standards
  • @smith-guidance/SKILL.md - AI agent behavior (HHH framework)

Before You Finish

Before implementing:

  1. Check for existing abstractions (DRY)
  2. Choose simplest approach (KISS)
  3. Confirm feature is needed now (YAGNI)
  4. Verify single responsibility (SOLID-S)