css-noop-checker: Skill for Claude Code

.claude/skills/vercel-composition-patterns/SKILL.md

vercel-composition-patterns is a skill for Claude Code from purupurupu/css-noop-checker. It costs 58 tokens per session (625 once invoked), scanned A, a copy of vercel-composition-patterns, MIT.

A set of guidelines for designing React components that stay flexible as an application grows. React is a JavaScript tool for building user interfaces; these guidelines cover ways to combine components, share state, and design reusable component interfaces.

In plain words
What is it for?
Use it when refactoring React components, building reusable component libraries, reviewing component architecture, or working with compound components, render props, context providers, and React 19 APIs.
Why use it?
It helps avoid components becoming difficult to maintain because they contain too many yes-or-no options. It provides patterns for keeping component behavior and structure easier for people and coding agents to understand.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions AGENTS.md.

This is purupurupu/css-noop-checker's own configuration. It tells Claude Code how to work on css-noop-checker itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything css-noop-checker configures →

Reuse

Borrowing it

Nothing to install: this file belongs to purupurupu/css-noop-checker. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/purupurupu/css-noop-checker/main/.claude/skills/vercel-composition-patterns/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/purupurupu/css-noop-checker

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for vercel-composition-patterns

README.md
[![agentmods](https://agentmods.dev/badge/skills/purupurupu/css-noop-checker/vercel-composition-patterns.svg)](https://agentmods.dev/skills/purupurupu/css-noop-checker/vercel-composition-patterns)
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<a href="https://agentmods.dev/skills/purupurupu/css-noop-checker/vercel-composition-patterns"><img src="https://agentmods.dev/badge/skills/purupurupu/css-noop-checker/vercel-composition-patterns.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 625 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 88% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00058 $0.00625
Opus 5 $0.00029 $0.00313
Sonnet 5 $0.00012 $0.00125
Haiku 4.5 $0.00006 $0.00063

Measured 8d ago against content hash 53d3156e8e76, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

vercel-composition-patterns scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

88% identical to vercel-composition-patterns — 4 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/skills/vercel-composition-patterns/SKILL.md · 89 lines

How it starts

The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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-
4 React 19 APIs MEDIUM react19-

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

4. React 19 APIs (MEDIUM)

⚠️ React 19+ only. Skip this section if using React 18 or earlier.

  • react19-no-forwardref - Don't use forwardRef; use use() instead of useContext()

Read the full file on GitHub · 89 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 89 lines · 58 tokens per session scan A 53d3156e8e76

Subscribe to this mod's changes

vercel-composition-patterns is a skill published in the GitHub repository purupurupu/css-noop-checker (24 stars, last pushed 5mo ago), licensed MIT. It adds 58 tokens to every session and 625 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 88% identical to vercel-composition-patterns, differing in 4 lines, and is treated as a copy.

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