---
name: verification-loop
description: Systematic verification before claiming completion — run tests, check coverage, verify edge cases, inspect CI. Use when about to mark a task done, before merge, or when user asks "is it ready?"
---

# Verification Loop Skill

Based on ECC verification-loop + verification-before-completion patterns.

## When to Use

- Before claiming any task is complete
- Before merge or PR
- User asks "is it ready?" or "có ổn chưa?"
- After fixing a bug

## Loop Steps

### 1. Run Tests
```bash
npm test          # or your test command
pytest tests/     # Python
go test ./...     # Go
```
If ANY test fails — FIX first, do NOT claim done.

### 2. Check Coverage
```bash
npm run coverage  # or equivalent
```
Thresholds:
- Line coverage: > 80%
- Branch coverage: > 70%
- Critical paths: 100% (auth, payments, data mutations)

### 3. Verify Edge Cases
For each input or parameter:
- null / None / undefined
- Empty string, empty array, empty object
- Maximum allowed length/value
- Minimum allowed length/value
- Special characters
- Boundary values (just above, just below limit)

### 4. Check for Regressions
```bash
git diff --name-only HEAD~1  # or relevant range
```
Verify changes don't break existing functionality. Run full test suite.

### 5. Lint and Type Check
```bash
npm run lint && npm run typecheck  # TypeScript
ruff check . && mypy .              # Python
golangci-lint run                    # Go
```

### 6. Review the Diff
```bash
git diff
```
Read every changed line. Verify:
- No accidental deletions
- No debug code left (print, console.log, debugger)
- No commented-out code
- No TODO without ticket reference
- Code matches what was asked

### 7. Build Check
```bash
npm run build    # or equivalent
```
Must succeed with zero errors.

## Decision

If ALL steps pass — safe to mark complete.
If ANY step fails — list issues, fix, re-run loop.

## Report Template

```
## Verification: [Task/Feature]
Tests: X/X pass (previously Y/Z)
Coverage: X% line (threshold: 80%), Y% branch (threshold: 70%)
Lint: clean / X warnings / X errors
Build: success / failed with [details]
Edge cases: all covered / gaps: [list]
Regressions: none / [list with test names]
Diff review: clean / issues: [list]

Status: READY / NOT READY
```