Clean Code Skill
When to use
- •Applying clean code principles to any codebase (Go, TypeScript, etc.)
- •Refactoring code to improve readability and maintainability
- •Reviewing code for clarity, simplicity, and adherence to standards
- •Ensuring consistent naming, structure, and organization
- •Removing unnecessary complexity, comments, or abstractions
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:
code
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
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 type checks pass? |
| ✅ Nothing forgotten? | Any edge cases missed? |
References
| File | Purpose |
|---|---|
| .cursor/rules/go-style-guide.mdc | Go coding standards, naming conventions, error handling, context usage, domain layer design, service patterns, testing conventions |
| .cursor/rules/frontend-patterns.mdc | TypeScript standards, React patterns, state management, code organization, unused imports/variables rules, control flow statement braces |