# Verification Pattern

Mandatory verification before claiming any work complete.

## Purpose

Prevent false completion claims. Every tool must specify how to verify it works.

## Core Rule

**Never claim work is complete without running verification.**

This applies to:
- Building new tools
- Modifying existing tools
- Fixing issues found in audits
- Any task that changes behavior

## Implementation Checklist

Tools implementing this pattern must:

- [ ] Declare verification method in tool definition
- [ ] Verification must be executable (not just "review")
- [ ] Run verification before completion claim
- [ ] Report verification output, not just "it passed"
- [ ] If verification fails, do not claim completion

## Verification Types

### Script-based
```yaml
verification:
  type: script
  command: python scripts/validate_skill.py <skill-path>
  success_criteria: "Exit code 0, no errors"
```

### Example-based
```yaml
verification:
  type: golden_examples
  examples_path: examples/
  check: "Output matches expected for all examples"
```

### Behavioral
```yaml
verification:
  type: behavioral
  test: "Invoke with test input, check output matches invariants"
  invariants_path: invariants.md
```

### Manual (last resort)
```yaml
verification:
  type: manual
  steps:
    - "Run skill with test case X"
    - "Verify output contains Y"
    - "Check file Z was created"
```

## Workflow Integration

```
Work complete?
    │
    ↓
Run verification ──→ Failed ──→ Fix issues ──→ (loop)
    │
    ↓
   Passed
    │
    ↓
Check golden examples ──→ Changed ──→ Flag for review
    │
    ↓
Report completion with verification output
```

## Anti-patterns

**Verification-by-assertion:** "I verified it works" without running anything. Always show evidence.

**Partial verification:** Checking one thing when multiple things changed. Verify all affected behaviors.

**Verification deferral:** "Will verify later." Verify now or don't claim completion.

**Silent failure:** Verification failed but reporting success. If it fails, say so.

## Evidence Format

When reporting completion, include:

```markdown
## Verification Results

**Method:** [script/examples/behavioral/manual]
**Command:** [what was run]
**Output:**
[actual output or summary]

**Status:** PASSED / FAILED
```

## Cross-references

- [Audit Pattern](audit-pattern.md) - Audits require verification of fixes
- [Reversion Protection](reversion-protection.md) - Golden examples are a verification method