verification-first

Verification-First Skill

Never claim completion without evidence. Verify before asserting.

Core Principle

"Trust, but verify" - Don't assume code works; prove it works.

Verification Protocol

Before Claiming "Done"

1. Run the Code

   • Execute the actual code path
   • Don't just read it and assume it works
   • Test with real inputs, not just mental simulation

2. Check the Output

   • Verify output matches expectations
   • Look at actual results, not just "no errors"
   • Compare against acceptance criteria

3. Test Edge Cases

   • What happens with empty input?
   • What happens with invalid input?
   • What happens at boundaries?

4. Verify in Context

   • Does it work in the actual environment?
   • Does it integrate correctly?
   • Are there side effects?

Verification Checklist

Before marking complete:

- [ ] Code compiles/transpiles without errors
- [ ] Tests pass (existing + new)
- [ ] Manual verification performed
- [ ] Edge cases checked
- [ ] Error handling works
- [ ] Integration verified

Anti-Patterns to Avoid

Don't Say

• ❌ "This should work..."
• ❌ "I believe this is correct..."
• ❌ "This looks right to me..."
• ❌ "Based on my understanding..."

Instead Say

• ✅ "I've verified this works by..."
• ✅ "Tests confirm this behavior..."
• ✅ "I ran this and observed..."
• ✅ "The output shows..."

Verification Methods

For Code Changes

# Type check
npx tsc --noEmit

# Run tests
npm test

# Build verification
npm run build

For Bug Fixes

1. Reproduce the bug first
2. Apply the fix
3. Verify bug no longer occurs
4. Verify no regression

For New Features

1. Write failing test first
2. Implement feature
3. Verify test passes
4. Test manually in UI/API

For Refactoring

1. Ensure tests exist (add if needed)
2. Make refactoring change
3. Verify all tests still pass
4. Verify behavior unchanged

Evidence Collection

When claiming completion, provide evidence:

## Verification Evidence

**What was verified:**

- Feature X works correctly

**How it was verified:**

- Ran `npm test` - 45/45 tests passing
- Manually tested in browser at /feature-x
- Checked error handling with invalid input

**Results observed:**

- Success case: Shows expected output
- Error case: Displays user-friendly message
- Edge case: Handles empty state gracefully

Confidence Levels

Integration with Workflow

Write code
    ↓
Run verification
    ↓
Evidence collected? ─No→ Verify more
    ↓ Yes
Claim completion with evidence

Remember

• No verification = No completion claim
• "It should work" is not verification
• Evidence beats confidence
• When in doubt, verify again