Feature Flags with Claude Code: Safe Deployments with Toggle Management

Feature flags let you deploy code without immediately exposing new features to all users. Claude Code can design a complete feature flag system — from definition to percentage rollouts — when given the right patterns. CLAUDE.md for Feature Flag Standards ## Feature Flag Rules ### When to use (required) - Any new feature affecting production behavior - A/B tests - Staged rollouts (5% → 50% → 100%) ### Implementation rules - Flag definitions: src/config/flags.ts (single source of truth) - Flag names: snake_case (new_checkout_flow, ai_recommendations) - Each flag must have: creation date, owner, expiry date in comment - Default value: always false (opt-in) - Maximum lifetime: 3 months → then delete ### Flag types 1. Release flags: turn feature on/off (delete when fully released) 2. Experiment flags: A/B tests (delete after experiment ends) 3. Operational flags: emergency kill switches (may persist longer) ### Prohibited - if (process.env.NODE_ENV === 'development') branching (use flags in