react-native-expert

A guide for building and troubleshooting mobile apps that run on both iPhone and Android using React Native and Expo. It covers app navigation, device-specific code, native modules, and mobile performance.

In plain words
What is it for?
Use it to set up navigation, connect native device features, diagnose Metro, Xcode, or Android build errors, and improve lists, images, and memory use.
Why use it?
It helps avoid common setup, build, and platform differences that can make one mobile app behave differently on iOS and Android.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/luizedupp/rememb/react-native-expert
Any agent
npx skills add LuizEduPP/Rememb --skill react-native-expert
Clone the repo
git clone --depth 1 https://github.com/LuizEduPP/Rememb

Made for: Claude Code, Codex.

Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,585 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00046 $0.01585
Opus 5 $0.00023 $0.00792
Sonnet 5 $0.00009 $0.00317
Haiku 4.5 $0.00005 $0.00159

Measured yesterday against content hash 8049acb37571, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

react-native-expert 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 yesterday.

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.

src/rememb_skills/react-native-expert/SKILL.md · 202 lines

How it starts

The opening of the file, as written. The whole thing — 202 lines — stays where its author put it; the contents beside it link to each section on GitHub.

React Native Expert

Senior mobile engineer building production-ready cross-platform applications with React Native and Expo.

Core Workflow

  1. Setup — Expo Router or React Navigation, TypeScript config → run npx expo doctor to verify environment and SDK compatibility; fix any reported issues before proceeding
  2. Structure — Feature-based organization
  3. Implement — Components with platform handling → verify on iOS simulator and Android emulator; check Metro bundler output for errors before moving on
  4. Optimize — FlatList, images, memory → profile with Flipper or React DevTools
  5. Test — Both platforms, real devices

Error Recovery

  • Metro bundler errors → clear cache with npx expo start --clear, then restart
  • iOS build fails → check Xcode logs → resolve native dependency or provisioning issue → rebuild with npx expo run:ios
  • Android build fails → check adb logcat or Gradle output → resolve SDK/NDK version mismatch → rebuild with npx expo run:android
  • Native module not found → run npx expo install <module> to ensure compatible version, then rebuild native layers

References

Load detailed guidance based on context:

Topic Reference Load When
Navigation references/expo-router.md Expo Router, tabs, stacks, deep linking
Platform references/platform-handling.md iOS/Android code, SafeArea, keyboard
Lists references/list-optimization.md FlatList, performance, memo
Storage references/storage-hooks.md AsyncStorage, MMKV, persistence
Structure references/project-structure.md Project setup, architecture

Constraints

MUST DO

  • Use FlatList/SectionList for lists (not ScrollView)
  • Implement memo + useCallback for list items
  • Handle SafeAreaView for notches
  • Test on both iOS and Android real devices
  • Use KeyboardAvoidingView for forms
  • Handle Android back button in navigation

MUST NOT DO

  • Use ScrollView for large lists
  • Use inline styles extensively (creates new objects)
  • Hardcode dimensions (use Dimensions API or flex)
  • Ignore memory leaks from subscriptions
  • Skip platform-specific testing
  • Use waitFor/setTimeout for animations (use Reanimated)

Read the full file on GitHub · 202 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 202 lines · 46 tokens per session scan A 8049acb37571

Subscribe to this mod's changes

react-native-expert is a skill published in the GitHub repository LuizEduPP/Rememb (4 stars, last pushed 1mo ago), licensed MIT. It adds 46 tokens to every session and 1,585 once invoked, about $0.0002 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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