---

name: vercel-composition-patterns description: React composition patterns that scale. Use when refactoring components with boolean prop proliferation, building flexible component libraries, or designing reusable APIs. Triggers on tasks involving compound components, render props, context providers, or component architecture. license: MIT metadata: author: vercel version: '1.0.0'

React Composition Patterns

Composition patterns for building flexible, maintainable React components. Avoid boolean prop proliferation by using compound components, lifting state, and composing internals. These patterns make codebases easier for both humans and AI agents to work with as they scale.

When to Apply

Reference these guidelines when:

• Refactoring components with many boolean props
• Building reusable component libraries
• Designing flexible component APIs
• Reviewing component architecture
• Working with compound components or context providers

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Component Architecture	HIGH	architecture-
2	State Management	MEDIUM	state-
3	Implementation Patterns	MEDIUM	patterns-

Quick Reference

1. Component Architecture (HIGH)

• architecture-avoid-boolean-props - Don't add boolean props to customize behavior; use composition
• architecture-compound-components - Structure complex components with shared context

2. State Management (MEDIUM)

• state-decouple-implementation - Provider is the only place that knows how state is managed
• state-context-interface - Define generic interface with state, actions, meta for dependency injection
• state-lift-state - Move state into provider components for sibling access

3. Implementation Patterns (MEDIUM)

• patterns-explicit-variants - Create explicit variant components instead of boolean modes
• patterns-children-over-render-props - Use children for composition instead of renderX props

How to Use

Read individual rule files for detailed explanations and code examples:

rules/architecture-avoid-boolean-props.md
rules/state-context-interface.md

Each rule file contains:

• Brief explanation of why it matters
• Incorrect code example with explanation
• Correct code example with explanation
• Additional context and references

Full Compiled Document

For the complete guide with all rules expanded: AGENTS.md

⚠️ よくある落とし穴

• boolean propを安易に追加してしまう: isCompact, isDisabled, showHeader のようなboolean propが増殖すると組み合わせ爆発を起こす。代わりにcomposition（children, compound components）で構造的に解決する
• Contextの過剰な再レンダリング: Provider の value に毎回新しいオブジェクトを渡すと、全consumerが再レンダリングされる。state, actions, meta を分離したcontext interfaceを設計し、useMemoで安定化させる
• render propsの乱用: renderHeader, renderFooter のようなrender propsはchildrenやcompound componentsで代替できるケースが多い。childrenを優先し、render propsは最後の手段とする