evidence-verification

What this skill does

# Evidence-Based Verification Skill

**Version:** 1.0.0
**Type:** Quality Assurance
**Auto-activate:** Code review, task completion, production deployment

## Overview

This skill teaches agents how to collect and verify evidence before marking tasks complete. Inspired by production-grade development practices, it ensures all claims are backed by executable proof: test results, coverage metrics, build success, and deployment verification.

**Key Principle:** Show, don't tell. No task is complete without verifiable evidence.

---

## When to Use This Skill

### Auto-Activate Triggers
- Completing code implementation
- Finishing code review
- Marking tasks complete in Squad mode
- Before agent handoff
- Production deployment verification

### Manual Activation
- When user requests "verify this works"
- Before creating pull requests
- During quality assurance reviews
- When troubleshooting failures

---

## Core Concepts

### 1. Evidence Types

**Test Evidence**
- Exit code (must be 0 for success)
- Test suite results (passed/failed/skipped)
- Coverage percentage (if available)
- Test duration

**Build Evidence**
- Build exit code (0 = success)
- Compilation errors/warnings
- Build artifacts created
- Build duration

**Deployment Evidence**
- Deployment status (success/failed)
- Environment deployed to
- Health check results
- Rollback capability verified

**Code Quality Evidence**
- Linter results (errors/warnings)
- Type checker results
- Security scan results
- Accessibility audit results

### 2. Evidence Collection Protocol

```markdown
## Evidence Collection Steps

1. **Identify Verification Points**
   - What needs to be proven?
   - What could go wrong?
   - What does "complete" mean?

2. **Execute Verification**
   - Run tests
   - Run build
   - Run linters
   - Check deployments

3. **Capture Results**
   - Record exit codes
   - Save output snippets
   - Note timestamps
   - Document environment

4. **Store Evidence**
   - Add to shared context
   - Reference in task completion
   - Link to artifacts
```

### 3. Verification Standards

**Minimum Evidence Requirements:**
- ✅ At least ONE verification type executed
- ✅ Exit code captured (0 = pass, non-zero = fail)
- ✅ Timestamp recorded
- ✅ Evidence stored in context

**Production-Grade Requirements:**
- ✅ Tests run with exit code 0
- ✅ Coverage >70% (or project standard)
- ✅ Build succeeds with exit code 0
- ✅ No critical linter errors
- ✅ Security scan passes

---

## Evidence Collection Templates

### Template 1: Test Evidence

Use this template when running tests:

```markdown
## Test Evidence

**Command:** `npm test` (or equivalent)
**Exit Code:** 0 ✅ / non-zero ❌
**Duration:** X seconds
**Results:**
- Tests passed: X
- Tests failed: X
- Tests skipped: X
- Coverage: X%

**Output Snippet:**
```
[First 10 lines of test output]
```

**Timestamp:** YYYY-MM-DD HH:MM:SS
**Environment:** Node vX.X.X, OS, etc.
```

### Template 2: Build Evidence

Use this template when building:

```markdown
## Build Evidence

**Command:** `npm run build` (or equivalent)
**Exit Code:** 0 ✅ / non-zero ❌
**Duration:** X seconds
**Artifacts Created:**
- dist/bundle.js (XXX KB)
- dist/styles.css (XXX KB)

**Errors:** X
**Warnings:** X

**Output Snippet:**
```
[First 10 lines of build output]
```

**Timestamp:** YYYY-MM-DD HH:MM:SS
```

### Template 3: Code Quality Evidence

Use this template for linting and type checking:

```markdown
## Code Quality Evidence

**Linter:** ESLint / Ruff / etc.
**Command:** `npm run lint`
**Exit Code:** 0 ✅ / non-zero ❌
**Errors:** X
**Warnings:** X

**Type Checker:** TypeScript / mypy / etc.
**Command:** `npm run typecheck`
**Exit Code:** 0 ✅ / non-zero ❌
**Type Errors:** X

**Timestamp:** YYYY-MM-DD HH:MM:SS
```

### Template 4: Combined Evidence Report

Use this comprehensive template for task completion:

```markdown
## Task Completion Evidence

### Task: [Task description]
### Agent: [Agent name]
### Completed: YYYY-MM-DD HH:MM:SS

### Verification Results

| Check | Command | Exit Code | Result |
|-------|---------|-----------|--------|
| Tests | `npm test` | 0 | ✅ 45 passed, 0 failed |
| Build | `npm run build` | 0 | ✅ Bundle created (234 KB) |
| Linter | `npm run lint` | 0 | ✅ No errors, 2 warnings |
| Types | `npm run typecheck` | 0 | ✅ No type errors |

### Coverage
- Statements: 87%
- Branches: 82%
- Functions: 90%
- Lines: 86%

### Evidence Files
- Test output: `.claude/quality-gates/evidence/tests-2025-XX-XX.log`
- Build output: `.claude/quality-gates/evidence/build-2025-XX-XX.log`

### Conclusion
All verification checks passed. Task ready for review.
```

---

## Step-by-Step Workflows

### Workflow 1: Code Implementation Verification

**When:** After writing code for a feature or bug fix

**Steps:**

1. **Save all files** - Ensure changes are written

2. **Run tests**
   ```bash
   npm test
   # or: pytest, cargo test, go test, etc.
   ```
   - Capture exit code
   - Note passed/failed counts
   - Record coverage if available

3. **Run build** (if applicable)
   ```bash
   npm run build
   # or: cargo build, go build, etc.
   ```
   - Capture exit code
   - Note any errors/warnings
   - Verify artifacts created

4. **Run linter**
   ```bash
   npm run lint
   # or: ruff check, cargo clippy, golangci-lint run
   ```
   - Capture exit code
   - Note errors/warnings

5. **Run type checker** (if applicable)
   ```bash
   npm run typecheck
   # or: mypy, tsc --noEmit
   ```
   - Capture exit code
   - Note type errors

6. **Document evidence**
   - Use Template 4 (Combined Evidence Report)
   - Add to shared context under `quality_evidence`
   - Reference in task completion message

7. **Mark task complete** (only if all evidence passes)

### Workflow 2: Code Review Verification

**When:** Reviewing another agent's code or user's PR

**Steps:**

1. **Read the code changes**

2. **Verify tests exist**
   - Are there tests for new functionality?
   - Do tests cover edge cases?
   - Are existing tests updated?

3. **Run tests**
   - Execute test suite
   - Verify exit code 0
   - Check coverage didn't decrease

4. **Check build**
   - Ensure project still builds
   - No new build errors

5. **Verify code quality**
   - Run linter
   - Run type checker
   - Check for security issues

6. **Document review evidence**
   - Use Template 3 (Code Quality Evidence)
   - Note any issues found
   - Add to context

7. **Approve or request changes**
   - Approve only if all evidence passes
   - If issues found, document them with evidence

### Workflow 3: Production Deployment Verification

**When:** Deploying to production or staging

**Steps:**

1. **Pre-deployment checks**
   - All tests pass (exit code 0)
   - Build succeeds
   - No critical linter errors
   - Security scan passes

2. **Execute deployment**
   - Run deployment command
   - Capture output

3. **Post-deployment checks**
   - Health check endpoint responds
   - Application starts successfully
   - No immediate errors in logs
   - Smoke tests pass

4. **Document deployment evidence**
   ```markdown
   ## Deployment Evidence

   **Environment:** production
   **Timestamp:** YYYY-MM-DD HH:MM:SS
   **Version:** vX.X.X

   **Pre-Deployment:**
   - Tests: ✅ Exit 0
   - Build: ✅ Exit 0
   - Security: ✅ No critical issues

   **Deployment:**
   - Command: `kubectl apply -f deployment.yaml`
   - Exit Code: 0 ✅

   **Post-Deployment:**
   - Health Check: ✅ 200 OK
   - Smoke Tests: ✅ All passed
   - Error Rate: <0.1%
   ```

5. **Verify rollback capability**
   - Ensure previous version can be restored
   - Document rollback procedure

---

## Evidence Storage

### Where to Store Evidence

**Shared Context** (Primary)
```json
{
  "quality_evidence": {
    "tests_run": true,
    "test_exit_code": 0,
    "coverage_percent": 87,
    "build_success": true,
    "build_exit_code": 0,
    "linter_errors": 0,
    "linter_warnings": 2,
    "timestamp": "2025-11-02T10:30:00Z"
  }
}
```

**Evidence Files** (Secondary)
- `.claude/quality-gate