---
name: doncheli-drift
description: Detect and reconcile divergence between specs and implementation. Activate when user mentions "drift", "sync", "spec divergence", "out of sync", "spec doesn't match", "implementation differs".
---

# Don Cheli: Spec Drift Detector

## Instructions

1. Read the current spec files in `.dc/specs/` and the relevant source code
2. Compare spec scenarios (Gherkin / acceptance criteria) against the actual implementation
3. Identify three categories of drift:
   - **Ghost**: code exists but no spec covers it
   - **Phantom**: spec exists but no code implements it
   - **Mutant**: code and spec exist but behavior diverges
4. For each drift finding, report: file path, spec reference, severity (critical / warning / info)
5. Propose a reconciliation: either update the spec or flag the code for correction
6. Never auto-modify code — output a reconciliation plan for human approval
7. Save a drift report to `.dc/drift-report-<date>.md` if findings exceed 3 items
8. If zero drift is found, confirm with a brief "No drift detected — spec and code are aligned"

## Output Format

```
## Drift Report — <date>

### Ghost (code without spec)
- src/payments/refund.ts:42 — no spec covers the refund edge case

### Phantom (spec without code)
- specs/checkout.feature:Scenario 3 — "Apply coupon on mobile" — not implemented

### Mutant (behavior mismatch)
- specs/auth.feature:Scenario 1 expects 401 on expired token; code returns 403

### Reconciliation Plan
1. [Phantom] Implement "Apply coupon on mobile" or mark as backlog in .dc/backlog.md
2. [Mutant] Fix auth.ts to return 401 — spec is correct per RFC 7235
3. [Ghost] Add spec for refund edge case before next release
```

## Do not use this skill when

- The user only wants to run tests (use doncheli-tea instead)
- The spec has not been written yet (use dc:especificar first)