expo/skills is a collection of instructions that help AI coding agents build, deploy, upgrade, and debug Expo applications. Developers use these skills when working with Expo, EAS, React Native, iOS, and Android workflows.
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.
npx agentmods add skills/expo/skills/eas-simulatornpx skills add expo/skills --skill eas-simulatorgit clone --depth 1 https://github.com/expo/skillsWrote 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.
[](https://agentmods.dev/skills/expo/skills/eas-simulator)<a href="https://agentmods.dev/skills/expo/skills/eas-simulator"><img src="https://agentmods.dev/badge/skills/expo/skills/eas-simulator.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00249 | $0.05766 |
| Opus 5 | $0.00125 | $0.02883 |
| Sonnet 5 | $0.00050 | $0.01153 |
| Haiku 4.5 | $0.00025 | $0.00577 |
Grade A, and why
eas-simulator 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 209 lines — stays where its author put it; the contents beside it link to each section on GitHub.
EAS Simulator
EAS service - costs apply. EAS Simulator runs on Expo Application Services cloud infrastructure, a paid product with free-tier limits; remote simulator sessions use your plan's compute allowance. See https://expo.dev/pricing.
EAS Simulator runs a remote iOS simulator or Android emulator on EAS infrastructure that you drive from your machine — from the CLI, from an AI agent (via agent-device), and from a browser preview. It's the unlock for environments that can't run a simulator locally (Linux boxes, cloud/background agents like Cursor Cloud), and for letting an agent verify a change on a real device instead of only reasoning about code.
The simulator:* commands are experimental and hidden, and need a recent eas-cli (≥ 20.3.0 as of writing) — which is why this skill runs everything via npx --yes eas-cli@latest. Flags and verbs may change; if a command fails, <cmd> --help is authoritative.
When to use
The frontmatter description carries the trigger phrases. In short: use this to get a user's app onto a cloud simulator and interact with it — especially from a Mac-less or cloud/sandbox agent. Not for local sims (expo run:ios, Xcode, Android Studio), store builds/signing (that's EAS Build), or physical devices. For the macOS case, see Cloud vs local next.
Cloud vs local: decide this first
- Non-macOS (Linux / CI / cloud sandbox like Cursor Cloud, detect via
uname -s≠Darwin): the only way to get a sim — proceed, once you've confirmed access (see Check availability first below). - macOS: local sims exist and a cloud session costs money + latency, so ask first ("a remote cloud sim — to share a live preview, offload, or test an iOS version you lack — or just run locally?") unless the user explicitly said cloud/remote/shareable.
- Always honor an explicit choice; for "run it locally" hand off to
expo run:ios/ Xcode.
# Programmatic detection — run this to decide before doing anything else:
if [ "$(uname -s)" != "Darwin" ] || ! xcrun --find simctl &>/dev/null 2>&1; then
echo "no local sim — proceed with EAS Simulator"
else
echo "local sim available — ask the user (cloud or local?)"
fi
What ships with it
4 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.
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.
- 6d ago First seen · 209 lines · 249 tokens per session scan A a204130df5b3
eas-simulator is a skill published in the GitHub repository expo/skills (2,501 stars, last pushed yesterday), licensed MIT. It adds 249 tokens to every session and 5,766 once invoked, about $0.0012 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.
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