---

name: ac-coverage scope: universal description: "[UDS] Analyze AC-to-test traceability and coverage" allowed-tools: Read, Grep, Glob argument-hint: "[spec file path | 規格檔案路徑]"

AC Coverage Assistant | AC 覆蓋率助手

Analyze Acceptance Criteria (AC) to test traceability and generate coverage reports.

分析驗收條件（AC）與測試之間的追蹤關係，並產生覆蓋率報告。

What This Does vs /coverage | 與 /coverage 的區別

| Aspect | /coverage | /ac-coverage | |--------|-------------|----------------| | Scope | Code-level (line/branch/function) | Requirement-level (AC-to-test) | | Input | Source code + test runner | SPEC file + test annotations | | Question | "How much code is tested?" | "Which AC have tests?" | | Output | Coverage percentages | Traceability matrix + gap report |

Workflow | 工作流程

1. Parse SPEC — Extract AC definitions (AC-1, AC-2, ...) from the specification file
2. Scan Tests — Search test files for @AC and @SPEC annotations using standard linking conventions
3. Build Matrix — Map each AC to its test references (file, test name, line)
4. Classify Status — Mark each AC as ✅ covered, ⚠️ partial, or ❌ uncovered
5. Calculate Coverage — Apply formula: Coverage % = (covered + partial × 0.5) / total × 100
6. Generate Report — Output standardized Markdown report

Linking Convention | 標註慣例

Tests MUST reference their source AC using standard annotations:

// TypeScript/JavaScript
describe('AC-1: User login with valid credentials', () => {
  // @AC AC-1
  // @SPEC SPEC-001
  it('should redirect to dashboard on successful login', () => { ... });
});

# Python
class TestAC1_UserLogin:
    """AC-1: User login with valid credentials
    @AC AC-1
    @SPEC SPEC-001
    """
    def test_redirect_to_dashboard(self): ...

# BDD Feature
@SPEC-001 @AC-1
Scenario: User login with valid credentials

Coverage Thresholds | 覆蓋率門檻

| Threshold | Default Value | Enforcement | |-----------|---------------|-------------| | Check-in | 80% | Required for feature branch merge | | Release | 100% | Required for production release | | Warning | 60% | Triggers coverage warning |

Thresholds are configurable via --threshold parameter or project configuration.

Report Format | 報告格式

The generated report follows the standard format from core/acceptance-criteria-traceability.md:

# AC Coverage Report

**Specification**: SPEC-001 — Feature Name
**Generated**: 2026-03-18
**Coverage**: 75% (6/8 AC)

## Summary

| Status | Count | Percentage |
|--------|-------|------------|
| ✅ Covered | 5 | 62.5% |
| ⚠️ Partial | 2 | 25.0% |
| ❌ Uncovered | 1 | 12.5% |

## Traceability Matrix

| AC-ID | Description | Status | Test Reference |
|-------|-------------|--------|----------------|
| AC-1 | Login with valid credentials | ✅ | auth.test.ts:15 |
| AC-2 | Reject invalid credentials | ✅ | auth.test.ts:32 |
| ...   | ...                        | ... | ... |

## Gaps
- **AC-8**: Social login — Blocked by OAuth sandbox

## Action Items
1. [ ] AC-8: Set up OAuth sandbox (ETA: TBD)

Next Steps Guidance | 下一步引導

After /ac-coverage completes, the AI assistant should suggest:

AC 覆蓋率分析完成。建議下一步 / AC coverage analysis complete. Suggested next steps:

• 覆蓋率達標 → 執行 /checkin 品質關卡 — Coverage meets threshold → Run /checkin quality gates
• 有未覆蓋 AC → 執行 /derive-tdd 補齊測試 — Uncovered AC found → Run /derive-tdd to add tests
• 有部分覆蓋 AC → 檢查缺少的邊界情況 — Partial AC → Review missing edge cases

Reference | 參考

• Core standard: acceptance-criteria-traceability.md
• SPEC: SPEC-AC-COVERAGE.md
• Related: test-coverage-assistant (code-level coverage)
• Related: checkin-assistant (quality gates)