Verification Loop Skill

A comprehensive verification system for Claude Code sessions.

When to Use

Invoke this skill:

• After completing a feature or significant code change
• Before creating a PR
• When you want to ensure quality gates pass
• After refactoring

Verification Phases

Phase 1: Build Verification

set -o pipefail  # report the build's exit status, not tail's
# Check if project builds
npm run build 2>&1 | tail -20
# OR
pnpm build 2>&1 | tail -20

If build fails, STOP and fix before continuing.

Phase 2: Type Check

set -o pipefail
# TypeScript projects
npx --no-install tsc --noEmit 2>&1 | sed -n '1,30p'

# Python projects
pyright . 2>&1 | sed -n '1,30p'

Report all type errors. Fix critical ones before continuing.

Phase 3: Lint Check

Use sed to limit displayed output while consuming the whole stream. This keeps a successful linter from failing on SIGPIPE when pipefail is enabled.

set -o pipefail
# JavaScript/TypeScript
npm run lint 2>&1 | sed -n '1,30p'

# Python
ruff check . 2>&1 | sed -n '1,30p'

Phase 4: Test Suite

set -o pipefail
# Run tests with coverage
npm run test -- --coverage 2>&1 | tail -50

# Check coverage threshold
# Target: 80% minimum

Report:

• Total tests: X
• Passed: X
• Failed: X
• Coverage: X%

Phase 5: Security Scan

# Check for secrets
grep -rn "sk-" --include="*.ts" --include="*.js" . 2>/dev/null | head -10
grep -rn "api_key" --include="*.ts" --include="*.js" . 2>/dev/null | head -10

# Check for console.log
grep -rn "console.log" --include="*.ts" --include="*.tsx" src/ 2>/dev/null | head -10

Phase 6: Diff Review

# Show what changed
git diff --stat
git diff HEAD~1 --name-only

Review each changed file for:

• Unintended changes
• Missing error handling
• Potential edge cases

Target Acceptance

When the requested outcome requires deployment or target-environment verification, report target acceptance separately from local checks. Record the environment and installed version when known, the evidence, and the next permitted check or precise access dependency. Passing local checks, review, merge, or release does not establish target acceptance. Report VERIFIED or FAILED for an executed target check, with its evidence. Do not access production or make external changes without authorization. For local-only tasks, mark target acceptance as not applicable.

For example: local checks PASS; staging verification NOT PERFORMED (no access); next step: an authorized maintainer runs the staging smoke test.

Output Format

After running all phases, produce a verification report:

VERIFICATION REPORT
==================

Build:     [PASS/FAIL]
Types:     [PASS/FAIL] (X errors)
Lint:      [PASS/FAIL] (X warnings)
Tests:     [PASS/FAIL] (X/Y passed, Z% coverage)
Security:  [PASS/FAIL] (X issues)
Diff:      [X files changed]

Overall:   [READY/NOT READY] for PR
Target:    [VERIFIED/FAILED/NOT PERFORMED/NOT APPLICABLE] (environment/version, evidence)
Next permitted step: [check or access dependency; none if complete/not applicable]

Issues to Fix:
1. ...
2. ...

Continuous Mode

For long sessions, run verification every 15 minutes or after major changes:

Set a mental checkpoint:
- After completing each function
- After finishing a component
- Before moving to next task

Run: /verify

Integration with Hooks

This skill complements PostToolUse hooks but provides deeper verification. Hooks catch issues immediately; this skill provides comprehensive review.