Overview

Toggle features without deployment using feature flags. Apply automatically when the request matches; the user does not need to mention this skill.

This skill should apply automatically when the request matches; the user does not need to mention this skill.

Workflow

1. Read the task-specific instructions in this file before acting.
2. Apply the documented constraints, resources, and verification steps.
3. Confirm the result against the requested outcome before completion.

Feature Flag System Skill

Implement feature flags to toggle features, run A/B tests, and control rollouts without redeployment.

Purpose

Enable gradual feature rollouts, A/B testing, kill switches, and environment-specific behavior.

When to Use

• Gradual feature rollouts (10% → 50% → 100%)
• A/B testing different versions
• Beta features for select users
• Kill switches for problematic features
• Environment-specific features

Quick Start

python3 /home/ubuntu/skills/feature-flag-system/scripts/setup_flags.py /path/to/project

Usage Example

import { useFeatureFlag } from '@/lib/flags'

export function Dashboard() {
  const { enabled } = useFeatureFlag('new_dashboard')
  
  if (enabled) return <NewDashboard />
  return <OldDashboard />
}

Common Patterns

Percentage Rollout

// Roll out to 25% of users
const rollout = 25
const userHash = hashUserId(user.id) % 100
if (userHash < rollout) {
  // Show new feature
}

User-Based Access

const betaUsers = ['user1', 'user2']
if (betaUsers.includes(user.id)) {
  // Show beta feature
}

Providers

• Vercel Flags - Built-in, free
• PostHog - Open source, analytics included
• LaunchDarkly - Enterprise-grade
• Split.io - A/B testing focused

Time Savings

Manual: 1-2 hours
With Skill: 10-15 minutes
Saved: ~1.5 hours per project

Files

• scripts/setup_flags.py - Automated setup
• templates/feature-flag.tsx - React hook
• references/flags_patterns.md - Best practices

Related Skills

• analytics-dashboard - Track flag usage
• deployment-automation - Deploy with flags
• testing-framework - Test flag variations

Ship features safely with instant rollback capability.