# Feature Flag Architecture

> Design and operate feature flags for safe rollouts, experimentation, and operational control. Use when introducing gradual releases, A/B tests, kill switches, or long-lived configuration toggles.

- Skill: `itsual/feature-flag-architecture` (Agent Skill)
- Install (CLI): `npx skillmds@latest add itsual/feature-flag-architecture`
- Raw SKILL.md: https://api.skillmd.com/api/skills/itsual/feature-flag-architecture/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: itsual (https://skillmd.com/u/itsual)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/itsual/feature-flag-architecture

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# Feature Flag Architecture

## Overview

Feature flags decouple deployment from release and enable safer delivery. They also add complexity and must be managed deliberately.

## When to Use

- Gradual or percentage rollouts
- Experiments and A/B tests
- Kill switches for risky features
- Trunk-based development with incomplete features

## Design Principles

- Short-lived flags are preferable to permanent ones
- Name flags clearly and include ownership/expiry information
- Avoid flag dependency spaghetti
- Clean up flags after full rollout or experiment conclusion
- Consider performance and consistency implications of flag evaluation

## Operational Checklist

- [ ] Flag has a clear owner and expected lifetime
- [ ] Default value is safe
- [ ] Monitoring exists for the new behavior
- [ ] Removal plan exists
- [ ] Evaluation points are consistent (especially in distributed systems)

## Verification

- Flags can be toggled without redeploying (where intended)
- Stale flags are tracked and removed
- Experiments have clear success metrics and end conditions