What is rn-best-practices?

A React Native development guide describes common practices for building mobile apps that run on iPhone and Android. React Native is a framework for creating both apps with shared code.

It is for building or reviewing React Native features, handling iOS and Android differences, and checking mobile UI and native-code decisions.

It helps avoid platform-specific bugs and common problems with layouts, images, lists, gestures, permissions, and app lifecycle behavior.

rn-best-practices — Skill for Claude Code and Codex by cmaranho

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add cmaranho/rn-agent-skills --skill rn-best-practices

Clone the repo

git clone --depth 1 https://github.com/cmaranho/rn-agent-skills

Made for: Claude Code, Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/cmaranho/rn-agent-skills/rn-best-practices/github.svg)](https://agentmods.dev/skills/cmaranho/rn-agent-skills/rn-best-practices)

Your own site

<a href="https://agentmods.dev/skills/cmaranho/rn-agent-skills/rn-best-practices"><img src="https://agentmods.dev/badge/skills/cmaranho/rn-agent-skills/rn-best-practices/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/cmaranho/rn-agent-skills/rn-best-practices"><img src="https://agentmods.dev/badge/skills/cmaranho/rn-agent-skills/rn-best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 454 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 original No closer match found 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.

Model	Per session	Once invoked
Fable 5.1	$0.00060	$0.00454
Opus 5	$0.00030	$0.00227
Sonnet 5	$0.00012	$0.00091
Haiku 4.5	$0.00006	$0.00045

Measured 11d ago against content hash cef64cf70abe, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

rn-best-practices 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 11d 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.

skills/rn-best-practices/SKILL.md · 52 lines

What it actually says

React Native — Boas Práticas

Objetivo

Escrever código RN idiomático, robusto entre plataformas e alinhado às capacidades da plataforma.

Quando utilizar

Construir/revisar componentes e features RN.
Lidar com diferenças iOS/Android, permissões ou APIs nativas.
Trabalhar com imagens, assets, listas, gestos, teclado ou safe area.

Conhecimentos necessários

APIs core do RN (View, Text, FlatList, Platform, Dimensions, Appearance).
Safe area, teclado, gestos e ciclo de vida do app (AppState).
Assets e imagens (densidades, cache, dimensionamento).
Uso e limites de módulos nativos.

Fluxo de execução

Prefira primitivos e libs mantidas da plataforma antes de código nativo.
Trate diferenças de plataforma explicitamente (Platform.select, arquivos .ios/.android).
Respeite safe area, teclado e orientação; layout responsivo.
Otimize imagens/assets e virtualize listas por padrão.
Teste em ambos os SOs e em tamanhos de tela distintos.

Boas práticas

Componentes pequenos e compostos; um por arquivo.
Estilos com tokens/tema; sem valores hardcoded ou estilos inline.
Cleanup de listeners/timers/subscriptions no unmount.
Trate permissões e estados negados com fallback.

Armadilhas comuns

Assumir paridade total entre iOS e Android.
Ignorar safe area/notch e teclado sobrepondo inputs.
Vazamento de listeners/timers.
ScrollView com muitos itens em vez de lista virtualizada.

Critérios de sucesso

Comportamento consistente em iOS e Android.
Sem vazamentos nem warnings de layout/lista.
UI responsiva e respeitando a plataforma.

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.

11d ago First seen · 52 lines · 60 tokens per session scan A cef64cf70abe

Subscribe to this mod's changes

rn-best-practices is a skill published in the GitHub repository cmaranho/rn-agent-skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 60 tokens to every session and 454 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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