whd4 Clean Code - Pragmatic AI Coding Standards
CRITICAL SKILL - Be concise, direct, and solution-focused.
Core Principles
| Principle | Rule |
|---|---|
| SRP | Single Responsibility - each function/class does ONE thing |
| DRY | Don't Repeat Yourself - extract duplicates, reuse |
| KISS | Keep It Simple - simplest solution that works |
| YAGNI | You Aren't Gonna Need It - don't build unused features |
| Boy Scout | Leave code cleaner than you found it |
Naming Rules
| Element | Convention |
|---|---|
| Variables | Reveal intent: userCount not n |
| Functions | Verb + noun: getUserById() not user() |
| Booleans | Question form: isActive, hasPermission, canEdit |
| Constants | SCREAMING_SNAKE: MAX_RETRY_COUNT |
Rule: If you need a comment to explain a name, rename it.
Function Rules
| Rule | Description |
|---|---|
| Small | Max 20 lines, ideally 5-10 |
| One Thing | Does one thing, does it well |
| One Level | One level of abstraction per function |
| Few Args | Max 3 arguments, prefer 0-2 |
| No Side Effects | Don't mutate inputs unexpectedly |
Code Structure
| Pattern | Apply |
|---|---|
| Guard Clauses | Early returns for edge cases |
| Flat > Nested | Avoid deep nesting (max 2 levels) |
| Composition | Small functions composed together |
| Colocation | Keep related code close |
AI Coding Style
| Situation | Action |
|---|---|
| User asks for feature | Write it directly |
| User reports bug | Fix it, don't explain |
| No clear requirement | Ask, don't assume |
Anti-Patterns (DON'T)
| ❌ Pattern | ✅ Fix |
|---|---|
| Comment every line | Delete obvious comments |
| Helper for one-liner | Inline the code |
| Factory for 2 objects | Direct instantiation |
| utils.ts with 1 function | Put code where used |
| "First we import..." | Just write code |
| Deep nesting | Guard clauses |
| Magic numbers | Named constants |
| God functions | Split by responsibility |
🔴 Before Editing ANY File (THINK FIRST!)
Before changing a file, ask yourself:
| Question | Why |
|---|---|
| What imports this file? | They might break |
| What does this file import? | Interface changes |
| What tests cover this? | Tests might fail |
| Is this a shared component? | Multiple places affected |
Quick Check:
File to edit: UserService.ts
└── Who imports this? → UserController.ts, AuthController.ts
└── Do they need changes too? → Check function signatures
🔴 Rule: Edit the file + all dependent files in the SAME task. 🔴 Never leave broken imports or missing updates.
Summary
| Do | Don't |
|---|---|
| Write code directly | Write tutorials |
| Let code self-document | Add obvious comments |
| Fix bugs immediately | Explain the fix first |
| Inline small things | Create unnecessary files |
| Name things clearly | Use abbreviations |
| Keep functions small | Write 100+ line functions |
Remember: The user wants working code, not a programming lesson.
🔴 Self-Check Before Completing (MANDATORY)
Before saying "task complete", verify:
| Check | Question |
|---|---|
| ✅ Goal met? | Did I do exactly what user asked? |
| ✅ Files edited? | Did I modify all necessary files? |
| ✅ Code works? | Did I test/verify the change? |
| ✅ No errors? | Lint and TypeScript pass? |
| ✅ Nothing forgotten? | Any edge cases missed? |
🔴 Rule: If ANY check fails, fix it before completing.
Verification Scripts (MANDATORY)
🔴 CRITICAL: Each agent runs ONLY their own skill's scripts after completing work.
Agent → Script Mapping
| Agent | Script | Command |
|---|---|---|
| frontend-specialist | UX Audit | python ~/.claude/skills/frontend-design/scripts/ux_audit.py . |
| frontend-specialist | A11y Check | python ~/.claude/skills/frontend-design/scripts/accessibility_checker.py . |
| backend-specialist | API Validator | python ~/.claude/skills/api-patterns/scripts/api_validator.py . |
| mobile-developer | Mobile Audit | python ~/.claude/skills/mobile-design/scripts/mobile_audit.py . |
| database-architect | Schema Validate | python ~/.claude/skills/database-design/scripts/schema_validator.py . |
| security-auditor | Security Scan | python ~/.claude/skills/vulnerability-scanner/scripts/security_scan.py . |
| seo-specialist | SEO Check | python ~/.claude/skills/seo-fundamentals/scripts/seo_checker.py . |
| seo-specialist | GEO Check | python ~/.claude/skills/geo-fundamentals/scripts/geo_checker.py . |
| performance-optimizer | Lighthouse | python ~/.claude/skills/performance-profiling/scripts/lighthouse_audit.py <url> |
| test-engineer | Test Runner | python ~/.claude/skills/testing-patterns/scripts/test_runner.py . |
| test-engineer | Playwright | python ~/.claude/skills/webapp-testing/scripts/playwright_runner.py <url> |
| Any agent | Lint Check | python ~/.claude/skills/lint-and-validate/scripts/lint_runner.py . |
| Any agent | Type Coverage | python ~/.claude/skills/lint-and-validate/scripts/type_coverage.py . |
| Any agent | i18n Check | python ~/.claude/skills/i18n-localization/scripts/i18n_checker.py . |
❌ WRONG:
test-engineerrunningux_audit.py✅ CORRECT:frontend-specialistrunningux_audit.py
🔴 Script Output Handling (READ → SUMMARIZE → ASK)
When running a validation script, you MUST:
- Run the script and capture ALL output
- Parse the output - identify errors, warnings, and passes
- Summarize to user in this format:
## Script Results: [script_name.py]
### ❌ Errors Found (X items)
- [File:Line] Error description 1
- [File:Line] Error description 2
### ⚠️ Warnings (Y items)
- [File:Line] Warning description
### ✅ Passed (Z items)
- Check 1 passed
- Check 2 passed
**Should I fix the X errors?**
- Wait for user confirmation before fixing
- After fixing → Re-run script to confirm
🔴 VIOLATION: Running script and ignoring output = FAILED task. 🔴 VIOLATION: Auto-fixing without asking = Not allowed. 🔴 Rule: Always READ output → SUMMARIZE → ASK → then fix.