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Get Started Free →Guide for making improvements to existing ClaudeBar functionality using TDD. Use this skill when: (1) Enhancing existing features (not adding new ones) (2) Improving UX, performance, or code quality (3) User asks "improve X", "make Y better", or "enhance Z" (4) Small enhancements that don't require full architecture design For NEW features, use implement-feature skill instead.
| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-19 | ✗→✓ | ▲ Improved | -2% | 0% |
| case-10 | ✗→✓ | ▲ Improved | 0% | 0% |
| case-11 | ✗→✓ | ▲ Improved | 51% | 0% |
| case-18 | ✗→✓ | ▲ Improved | -11% | 0% |
| case-04 | ✓→✗ | ▼ Worse | -43% | 0% |
Make improvements to existing functionality using TDD and rich domain design.
| Scenario | Skill to Use | |----------|--------------| | Enhance existing behavior | improvement (this skill) | | Fix broken behavior | fix-bug | | Add new feature | implement-feature | | Add new AI provider | add-provider |
┌─────────────────────────────────────────────────────────────┐
│ 1. UNDERSTAND CURRENT STATE │
├─────────────────────────────────────────────────────────────┤
│ • Read existing code │
│ • Understand current behavior │
│ • Identify what to improve │
└─────────────────────────────────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────────┐
│ 2. WRITE TEST FOR IMPROVED BEHAVIOR (Red) │
├─────────────────────────────────────────────────────────────┤
│ • Test describes the IMPROVED behavior │
│ • Test should FAIL initially │
│ • Keep existing tests passing │
└─────────────────────────────────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────────┐
│ 3. IMPLEMENT & VERIFY (Green) │
├─────────────────────────────────────────────────────────────┤
│ • Implement the improvement │
│ • New test PASSES │
│ • All existing tests still pass │
└─────────────────────────────────────────────────────────────┘Enhance user experience without changing core logic:
Examples:
- Settings view scrolls on small screens
- Better loading indicators
- Improved accessibility
- Cleaner visual layoutTest approach: UI behavior tests or manual verification
Enhance domain model behavior:
Examples:
- Add computed property for common queries
- Improve status calculation
- Add convenience methods
- Better encapsulationTest approach: State-based domain tests
swift@Test func `model provides convenient access to lowest quota`() { // Given let snapshot = UsageSnapshot(quotas: [quota1, quota2, quota3]) // Then - new convenience property #expect(snapshot.lowestQuota == quota2) }
Enhance probes, storage, or adapters:
Examples:
- Better error messages
- More robust parsing
- Improved timeout handling
- Caching supportTest approach: Behavior tests with mocked dependencies
Optimize existing functionality:
Examples:
- Reduce redundant API calls
- Lazy loading
- Parallel execution
- CachingTest approach: Behavior tests (same results, better performance)
swift@Suite struct {Component}Tests { @Test func `{describes improved behavior}`() { // Given - standard setup let component = Component(...) // When - action let result = component.improvedMethod() // Then - verify improved behavior #expect(result.hasImprovedProperty) } }
Improvements should NOT break existing behavior:
bash# Run all tests to ensure no regressions swift test
> Full documentation: docs/ARCHITECTURE.md
| Layer | Location | Improvement Examples | |-------|----------|---------------------| | Domain | Sources/Domain/ | New computed properties, convenience methods | | Infrastructure | Sources/Infrastructure/ | Better parsing, error handling | | App | Sources/App/ | UI enhancements, accessibility |
swift test)Other measured skills in the registry, with their headline benchmark lift.