Claude Skill Flaky Test Detector — Testing skill for Claude Code

Flaky Test Detector

A Claude Code skill for detecting flaky test patterns that cause intermittent CI failures.

Installation

As a Claude Code Skill

# Clone to your Claude skills directory
git clone https://github.com/wrsmith108/claude-skill-flaky-test-detector.git ~/.claude/skills/flaky-test-detector

Standalone Usage

# Run directly with npx
npx tsx scripts/index.ts [directory] [options]

Trigger Phrases

This skill activates when you mention:

• "flaky test"
• "intermittent failure"
• "test sometimes fails"
• "race condition in test"
• "timing issue in test"
• "test passes locally but fails in CI"
• "non-deterministic test"

Pattern Detection

Scans `*.test.ts` and `*.spec.ts` files to detect:

Severity	Pattern	Risk
HIGH	1-second TTL	Second-boundary race conditions
HIGH	Math.floor(Date.now() / 1000)	Second truncation timing edge cases
HIGH	Very short setTimeout (<100ms)	Unreliable timeouts
MEDIUM	Date.now() without mocking	Real time causes non-determinism
MEDIUM	new Date() without mocking	Real date causes flakiness
MEDIUM	Low timeout values	Race conditions in CI
LOW	Math.random() without seeding	Non-reproducible behavior
LOW	process.nextTick in assertions	Timing-dependent assertions

Usage

Scan Current Directory

# Run the detector on all test files
npx tsx scripts/index.ts

# Scan specific directory
npx tsx scripts/index.ts ./src/tests

# Output as JSON
npx tsx scripts/index.ts --json

# CI mode: exit with code 1 if HIGH severity issues found
npx tsx scripts/index.ts --ci

Options

Option	Description
--json	Output results as JSON
--ci	CI mode: exit with code 1 if HIGH severity issues found
--quiet	Suppress output except errors
--help	Show help message

Output Example

## Flaky Test Analysis

Scanned 94 test f