Codex Phone Lab

Prompt to phone app.

codex-phone-lab installs a Codex skill that helps Codex create Expo/React Native apps and open them on a real iPhone or Android device through Expo Go.

No Xcode setup. No TestFlight. No App Store wait.

npx --yes codex-phone-lab

Then use it in Codex:

Use $codex-phone-lab and make me a notes app for my phone.

What It Does

• Checks the local Node/npm/Expo environment.
• Creates Expo SDK 54 apps by default so they work with the current Expo Go workflow.
• Starts the Expo phone preview server.
• Shows the QR flow for Expo Go.
• Guides Codex to build real mobile screens instead of generic landing pages.
• Keeps the live loop: prompt, code, phone refresh.

Why

Codex can write mobile code, but the phone loop is usually the slow part.

This skill packages the workflow:

prompt -> Expo app -> QR code -> real phone -> live edits

It is meant for quick MVPs, app ideas, prototypes, demos, and internal tools.

Requirements

• Node.js and npm.
• Expo Go installed on your iPhone or Android phone.
• Phone and computer on the same Wi-Fi for LAN mode.

If LAN mode fails, use tunnel mode:

~/.codex/skills/codex-phone-lab/scripts/start-phone-preview.sh tunnel

Commands

After installation, the skill lives at:

~/.codex/skills/codex-phone-lab

Create a new Expo app:

~/.codex/skills/codex-phone-lab/scripts/new-expo-app.sh my-phone-app

Start the phone preview:

cd my-phone-app
~/.codex/skills/codex-phone-lab/scripts/start-phone-preview.sh lan

Run a quick environment check:

~/.codex/skills/codex-phone-lab/scripts/doctor.sh

Expo SDK Version

The skill defaults to:

expo-template-default@sdk-54

This avoids the common Expo Go error:

Project is incompatible with this version of Expo Go

Override the template only when your Expo Go supports a newer SDK:

CODEX_PHONE_LAB_EXPO_TEMPLATE=expo-template-default@sdk-55 \
  ~/.codex/skills/codex-phone-lab/scripts/new-expo-app.sh my-app

License

MIT