| name | drift-analysis |
| description | Use when: checking spec-vs-code fidelity, finding orphaned acceptance criteria, finding orphaned tests, detecting stale specifications, running sdd analyze drift, auditing traceability health |
| tags | ["drift","traceability","brownfield","spec-code-fidelity","orphaned","stale"] |
Drift Analysis Skill
Purpose
Detect spec-vs-code drift by cross-referencing specification acceptance criteria
against test files via traceability IDs. Surfaces three categories of drift that
erode confidence in long-lived projects.
Workflow — sdd analyze drift
- Read specs: scan
.specify/specs/*/spec.md for AC identifiers (AC-NNN)
- Read tests: scan test files for traceability references (AC-NNN in comments,
test names, or
Traces To: annotations)
- Cross-reference: match each AC to its covering test(s) via traceability IDs
- Detect drift: classify each AC/test into one of three drift categories
Drift Categories
| Category | Definition | Severity |
|---|
| Orphaned AC | AC exists in spec but has no matching test | WARN |
| Orphaned Test | Test references an AC that no longer exists in any spec | WARN |
| Stale AC | AC has a covering test, but the test has not been modified since the last spec change | INFO |
Output Format
| Spec | AC | Status | Test File | Last Verified |
|------|-----|--------|-----------|---------------|
| 001-auth | AC-001 | ✅ Covered | auth.spec.ts | 2026-05-10 |
| 001-auth | AC-002 | ⚠️ Orphaned AC | — | — |
| — | — | ⚠️ Orphaned Test | legacy.spec.ts:TC-099 | 2026-03-15 |
| 002-orders | AC-005 | ℹ️ Stale | orders.spec.ts | 2026-01-20 |
Integration
- Integrates with
sdd status for projects with ≥ 5 completed specs
- Can be run as a pre-review lint pass via
sdd doctor --drift
- Results feed into the reviewer agent's Pass 1 (Spec Compliance)
Suppression
- Mark an AC as intentionally untested:
<!-- drift:suppress AC-NNN reason -->
- Mark a test as legacy/exempt:
// drift:exempt TC-NNN reason
File Pattern Defaults
- Specs:
.specify/specs/*/spec.md
- Tests:
**/*.spec.ts, **/*.test.ts, **/*.spec.js, **/*.test.js,
**/*Test.java, **/*_test.py, **/*_test.go
- Configurable via
.sdd/config → drift.spec_patterns / drift.test_patterns
