expo

expo is a skill for Claude Code, Codex from pproenca/dot-skills. It costs 57 tokens per session (1,398 once invoked), scanned A, original, MIT.

A set of performance guidelines for Expo React Native apps, which are mobile applications built with React Native and the Expo toolkit. It covers startup, bundle size, lists, images, navigation, rendering, animations, and memory.

In plain words
What is it for?
Use it when writing or reviewing Expo code, improving launch time, tuning lists and images, optimising navigation and animations, reducing bundle size, or managing memory.
Why use it?
It helps find common causes of slow startup, sluggish screens, unnecessary re-renders, large app bundles, and high memory use. The rules organise improvements by area and expected impact.

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/pproenca/dot-skills/expo
Any agent
npx skills add pproenca/dot-skills --skill expo
Clone the repo
git clone --depth 1 https://github.com/pproenca/dot-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.

agentmods badge for expo

README.md
[![agentmods](https://agentmods.dev/badge/skills/pproenca/dot-skills/expo.svg)](https://agentmods.dev/skills/pproenca/dot-skills/expo)
Your own site
<a href="https://agentmods.dev/skills/pproenca/dot-skills/expo"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/expo.svg" alt="Measured on agentmods" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,398 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 $0.00057 $0.01398
Opus 5 $0.00028 $0.00699
Sonnet 5 $0.00011 $0.00280
Haiku 4.5 $0.00006 $0.00140

Measured 5d ago against content hash cf591e4df0a6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

expo 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 5d 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/.curated/expo/SKILL.md · 127 lines

How it starts

The opening of the file, as written. The whole thing — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Community Expo React Native Best Practices

Comprehensive performance optimization guide for Expo React Native applications. Contains 54 rules across 9 categories, prioritized by impact to guide automated refactoring and code generation.

When to Apply

Reference these guidelines when:

  • Writing new Expo React Native components
  • Optimizing app startup and Time to Interactive
  • Implementing lists, images, or animations
  • Reducing bundle size and memory usage
  • Reviewing code for mobile performance issues

Rule Categories by Priority

Priority Category Impact Prefix
1 Launch Time Optimization CRITICAL launch-
2 Bundle Size Optimization CRITICAL bundle-
3 List Virtualization HIGH list-
4 Image Optimization HIGH image-
5 Data Fetching Patterns HIGH data-
6 Navigation Performance MEDIUM-HIGH nav-
7 Re-render Prevention MEDIUM rerender-
8 Animation Performance MEDIUM anim-
9 Memory Management LOW-MEDIUM mem-

Quick Reference

1. Launch Time Optimization (CRITICAL)

  • launch-splash-screen-control - Control splash screen visibility during asset loading
  • launch-preload-critical-assets - Preload fonts and images during splash
  • launch-hermes-engine - Use Hermes engine for faster startup
  • launch-defer-non-critical - Defer non-critical initialization
  • launch-new-architecture - Enable New Architecture for synchronous native communication
  • launch-minimize-root-imports - Minimize imports in root App component

2. Bundle Size Optimization (CRITICAL)

  • bundle-avoid-barrel-files - Avoid barrel file imports
  • bundle-analyze-size - Analyze bundle size before release
  • bundle-remove-unused-dependencies - Remove unused dependencies
  • bundle-split-by-architecture - Generate architecture-specific APKs
  • bundle-enable-proguard - Enable ProGuard for Android release builds
  • bundle-optimize-fonts - Subset custom fonts to used characters
  • bundle-use-lightweight-alternatives - Use lightweight library alternatives

Read the full file on GitHub · 127 lines

Files

What ships with it

59 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. 5d ago First seen · 127 lines · 57 tokens per session scan A cf591e4df0a6

Subscribe to this mod's changes

expo is a skill published in the GitHub repository pproenca/dot-skills (202 stars, last pushed 20d ago), licensed MIT. It adds 57 tokens to every session and 1,398 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 2026-08-30.

Related

Other skills, from other repositories

agent-spec-mobile-react-native

Agent skill for spec-mobile-react-native - invoke with $agent-spec-mobile-react-native.

ruvnet/ruflo · 22 tokens

vercel-react-native-skills

React Native and Expo best practices for building performant mobile apps. Use when building React Native components, optimizing list performance, implementing animations, or working with native modules. Triggers on tasks involving React Native, Expo, mobile performance, or native platform APIs.

zhukunpenglinyutong/desktop-cc-gui · 57 tokens

react-native-testing

Write tests using React Native Testing Library (RNTL) v13 and v14 (@testing-library/react-native). Use when writing, reviewing, or fixing React Native component tests. Covers: render, screen, queries (getBy/getAllBy/queryBy/findBy), Jest matchers, userEvent, fireEvent, waitFor, and async patterns. Supports v13 (React…

callstack/react-native-testing-library · 134 tokens

expo-native-ui

Framework (OSS). Build beautiful, native-feeling Expo screens. Covers Apple HIG styling, semantic colors, native controls, SF Symbols, media, animations, visual effects, gradients, storage, and responsive layout. For routing and navigation, use the expo-router skill.

expo/skills · 58 tokens

expo-web-to-native

Framework (OSS). Migrate an existing web React app to a native iOS/Android app with Expo. Use when the user wants to turn a website into a mobile app, port a Next.js/Vite/CRA React codebase to React Native, reuse web code on native incrementally, or asks how web idioms (the DOM, CSS, React Router, localStorage…

expo/skills · 111 tokens

truesheet-usage

Consumer-side guide for integrating @lodev09/react-native-true-sheet into a React Native app. Use this skill whenever the user wants to add, configure, control, or debug a bottom sheet using TrueSheet — including ref-based sheets, named global sheets, web support with TrueSheetProvider/useTrueSheet, React Navigation…

lodev09/react-native-true-sheet · 169 tokens