- name
- ac-coverage
- scope
- universal
- anchor_standard
- acceptance-criteria-traceability
- description
- [UDS] Analyze AC-to-test traceability and generate requirement-level coverage reports.
Use when: auditing which acceptance criteria have tests, building a traceability matrix from a SPEC file, finding uncovered AC before release.
Not for: code-level line/branch/function coverage — use /coverage; writing the missing tests — use /tdd or /spec-derive.
Keywords: AC coverage, traceability, acceptance criteria, SPEC, traceability matrix, 驗收條件, 需求追蹤, 覆蓋率矩陣.
- 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
**Version**: 1.1.0
**Last Updated**: 2026-06-19
**Applicability**: Claude Code Skills
> **Core Standard**: This skill implements [Acceptance Criteria Traceability Standards](../../core/acceptance-criteria-traceability.md). For the authoritative methodology, refer to the core standard.
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 the **canonical annotation** `@SPEC-<id> @AC-<n>` (a single combined tag)
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 the **canonical annotation**:
`@SPEC-<id> @AC-<n>` — a single combined tag, e.g. `@SPEC-001 @AC-1`. Keeping the
attribution on **one line** is what forward-derivation and test-runner tag
filters consume. **Do not** split it into separate `@AC` / `@SPEC` lines.
使用**標準合併標註** `@SPEC-<id> @AC-<n>`(單一合併標籤),保持同一行;**勿**拆成 `@AC` / `@SPEC` 兩行。
```typescript
// TypeScript/JavaScript
describe('AC-1: User login with valid credentials', () => {
// @SPEC-001 @AC-1
it('should redirect to dashboard on successful login', () => { ... });
});
```
```python
# Python
class TestAC1_UserLogin:
"""AC-1: User login with valid credentials
@SPEC-001 @AC-1
"""
def test_redirect_to_dashboard(self): ...
```
```gherkin
# 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.
## Four-Layer Traceability | 四層追溯(`--full` 模式)
Use `--full` flag to extend from 2-layer (AC→Test) to 4-layer traceability.
使用 `--full` 標記將追溯從 2 層(AC→Test)擴展為 4 層。
### Traceability Layers | 追溯層次
```
Layer 0: Requirement / User Story (REQ)
↓ (defines)
Layer 1: Acceptance Criteria (AC)
↓ (@SPEC-NNN @AC-N annotations)
Layer 2: Test Cases
↓ (covers)
Layer 3: Source Code (@implements)
```
### Layer Annotations | 各層標註慣例
```typescript
// Layer 3→1: Code referencing AC
// @implements AC-1, AC-2
function authenticate(user: string, pass: string) { ... }
```
```markdown
<!-- Layer 0→1: Requirement in SPEC -->
## Requirements
### REQ-1: User Authentication
- AC-1: Given valid credentials, when login, then authenticated
- AC-2: Given invalid credentials, when login, then rejected
```
### Full Traceability Report | 完整追溯報告
```markdown
## Four-Layer Traceability Matrix
| Requirement | AC | Test | Code | Status |
|-------------|-----|------|------|--------|
| REQ-1 | AC-1 | auth.test.ts:15 | auth.ts:42 | ✅ Full |
| REQ-1 | AC-2 | auth.test.ts:30 | auth.ts:58 | ✅ Full |
| REQ-2 | AC-3 | — | dashboard.ts:10 | ⚠️ No test |
| REQ-3 | AC-4 | export.test.ts:5 | — | ⚠️ No code |
### Gap Summary
- Layer 0→1: 2 requirements without AC
- Layer 1→2: 1 AC without tests
- Layer 2→3: 0 tests without code mapping
- Layer 3→1: 3 code files without AC mapping
```
### Reverse Tracing | 反向追溯
Use `--trace-code <path>` to trace from code back to requirements.
使用 `--trace-code <path>` 從程式碼反向追溯到需求。
```bash
/ac-coverage --trace-code src/auth.ts
# Output:
# src/auth.ts:42 → @implements AC-1 → REQ-1 (SPEC-AUTH-001)
# src/auth.ts:58 → @implements AC-2 → REQ-1 (SPEC-AUTH-001)
```
## Report Format | 報告格式
The generated report follows the standard format from `core/acceptance-criteria-traceability.md`:
```markdown
# 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 ⭐ **Recommended / 推薦** — 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
> - 需要完整追溯 → 執行 `/ac-coverage --full` — Need full traceability → Run with `--full`
> - 反向追溯 → 執行 `/ac-coverage --trace-code <path>` — Reverse trace → Use `--trace-code`
## Reference | 參考
- Core standard: [acceptance-criteria-traceability.md](../../core/acceptance-criteria-traceability.md)
- SPEC: [SPEC-AC-COVERAGE.md](../../docs/specs/skills/SPEC-AC-COVERAGE.md)
- Related: [test-coverage-assistant](../test-coverage-assistant/SKILL.md) (code-level coverage)
- Related: [checkin-assistant](../checkin-assistant/SKILL.md) (quality gates)
## AI Agent Behavior | AI 代理行為
> 完整的 AI 行為定義請參閱對應的命令文件:[`/ac-coverage`](../commands/ac-coverage.md#ai-agent-behavior--ai-代理行為)
>
> For complete AI agent behavior definition, see the corresponding command file: [`/ac-coverage`](../commands/ac-coverage.md#ai-agent-behavior--ai-代理行為)
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