Mobile: emulator run proof + EAS CI / Expo account setup

Mobile: emulator run proof + EAS CI / Expo account setup

1. Proof of life (2026-05-30)

The mental-tracker app, generated by vox build --target=mobile, was run on a live Android emulator (Medium_Phone_API_36.1, Expo Go / SDK 52). Every RN-codegen fix landed this cycle was verified visually and interactively:

What	Evidence
App compiles + bundles (Metro → Hermes 3 MB .hbc)	npx expo export succeeds
Home screen renders natively (heading, subtitle, styled buttons)	assets/mobile-proof-2026/home-screen.png
Interactivity: useState + onPress + set_x rewrite	counter 0 → 3 after taps — assets/mobile-proof-2026/home-counter-3.png
Navigation: link(href) → expo-router <Link>	tap “Timeline” routes index → timeline — assets/mobile-proof-2026/timeline-screen.png
Lifecycle: on mount: async load (awaited)	Timeline shows “Events stored: 0” (the awaited health_event_count() result)
Cross-component import	NavBar renders on every screen

Data fetches return empty/0 because no backend was running — the app degrades gracefully (the generated match Ok/Error handles the rejected fetch). A real run points EXPO_PUBLIC_VOX_API_URL at a Vox server.

2. Run the generated app on an Android emulator (reproducible)

This path uses Expo Go + a JS shim for @vox/runtime-rn, so it needs no native build — it proves the UI/navigation/lifecycle codegen. (The native runtime ships via a dev client / EAS Build; see §4.)

# 0. Prereqs: Android SDK (emulator + platform-tools), Node 20+, an AVD.
export ANDROID_HOME="$LOCALAPPDATA/Android/Sdk"          # Windows path shown
export PATH="$ANDROID_HOME/platform-tools:$ANDROID_HOME/emulator:$PATH"
emulator -avd <your_avd> -no-snapshot-save &             # boot emulator

# 1. Generate the Expo app.
vox build apps/vox-mental-tracker/src/main.vox --target=mobile -o /tmp/voxapp

# 2. Swap the native runtime for the CI JS shim (in this repo).
cp -r ci/expo-bundle-shim/vox-runtime-rn /tmp/voxapp/shims-vox-runtime-rn
#    package.json: set "@vox/runtime-rn": "file:./shims-vox-runtime-rn",
#    and drop "@vox/runtime-types" (types only; not needed at runtime).

# 3. Placeholder app icon/splash (the generator references ./assets/splash.png).
mkdir -p /tmp/voxapp/assets   # drop any PNG named splash.png / icon.png here

# 4. Install + run.
cd /tmp/voxapp
npm install
npx expo start                # Metro only (headless-friendly)

# 5. Launch on the emulator (in another shell):
adb reverse tcp:8081 tcp:8081
adb shell am start -a android.intent.action.VIEW \
  -d "exp://127.0.0.1:8081" host.exp.exponent
adb exec-out screencap -p > screen.png   # capture proof

Notes:

• adb reverse lets the emulator reach the host’s Metro on 127.0.0.1:8081.
• If port 8081 is held, kill the stale Metro (Get-NetTCPConnection -LocalPort 8081 | Stop-Process … on Windows) before restarting.
• npx expo start --android auto-opens but prompts interactively (Expo Go version) — the adb deep-link above avoids that in non-interactive shells.

3. Create an Expo account (manual — one-time)

EAS Build (cloud APK/IPA builds) needs a free Expo account. These steps are interactive and must be done by a human:

1. Sign up at https://expo.dev/signup.
2. npm i -g eas-cli && eas login.
3. From a generated app dir (/tmp/voxapp), run eas init to create/link an EAS project (writes the projectId into app.json → extra.eas). Commit that projectId back into the generator if you want it baked in.
4. Create a CI token: https://expo.dev/settings/access-tokens → “Create token”. Copy it.
5. Add it as a GitHub Actions secret named EXPO_TOKEN (Repo → Settings → Secrets and variables → Actions → New repository secret).

4. CI runner — mobile-eas-build.yml

.github/workflows/mobile-eas-build.yml has two jobs:

• bundle — runs on every mobile-touching push/PR, no account needed. It generates the Expo app, swaps in ci/expo-bundle-shim/vox-runtime-rn, installs deps, and runs npx expo export. This is the real gate: it fails if the generated app doesn’t bundle (exactly the class of bug — import.meta, missing zod — that the emulator run surfaced). Active now.
• eas-build — runs only on workflow_dispatch and when EXPO_TOKEN is set. Submits a cloud Android APK build via eas build. Skips cleanly until you complete §3, so the workflow is green from day one.

Remaining to fully automate device E2E

• iOS is unverified (no macOS host) — see vox-runtime-rn-mobile-cross-compile.md TODO(ios-cross-compile) and the #[ignore]d gate in crates/vox-cli-tests/tests/mobile_cross_compile.rs.
• On-emulator E2E in CI (Maestro/Detox driving the booted app) is the natural next step on top of the bundle gate; tracked in mobile-e2e-testing-strategy-2026.md.

5. Codegen gaps this run surfaced (now fixed)

The emulator run found bugs that static builds didn’t, all fixed in the RN codegen this cycle (see git log on mobile/rn-expo-foundation):

• vox-client.ts emitted import.meta.env (Hermes parse error) → target-aware base-URL resolution (process.env.EXPO_PUBLIC_VOX_API_URL for RN).
• generated package.json missing zod + expo-asset; version skew on react-native / expo-status-bar → pinned to SDK-52-compatible versions.
• link(href) rendered inert; on-mount data never loaded; endpoint calls sent positional args — all fixed earlier in the cycle.