CAST Android private beta setup
CAST downloads as an APK file. Open the downloaded APK, install it, then set up the local Gemma model from inside CAST.
- Tap Download Android APK.
- Open
cast-v63-private-beta.apkfrom the Chrome download notification, Chrome menu > Downloads, or Files > Downloads. - If Android blocks the install, allow installs from Chrome or Samsung Internet.
- If Android says App not installed, uninstall any old CAST beta, then open the APK again.
- Open CAST, create or enter the beta account, and complete the short setup flow.
- Use Model setup to download the local Gemma 4 E2B
.litertlmmodel. If the model is already in Downloads, use Import model file and choose it from Android's picker. - Start with one real problem and confirm the app returns the read, the risk, and the next move.
- Open Tools, export a brief, and send beta feedback before calling the install complete.
Simple tester version
Use this if someone says they downloaded it but cannot find what to tap next.
- Open Chrome on the Android phone.
- Go to
https://beta.castbystella.com. - Tap Download Android APK.
- Wait until the download finishes. Do not tap the same download button over and over.
- If a download bar or notification appears, tap Open.
- If nothing opens, tap the three dots in Chrome, tap Downloads, then tap
cast-v63-private-beta.apk. - If it is not in Chrome, open the phone's Files app, open Downloads, then tap
cast-v63-private-beta.apk. - If Android asks whether Chrome can install unknown apps, tap Settings, turn on Allow from this source, then go back and tap Install.
- If Android says App not installed, uninstall the old CAST beta first, then open the APK again.
- Open CAST after install.
Model setup
Use Gemma 4 `.litertlm` model files. E2B is the private beta default because it is lighter and easier to keep responsive. E4B is the higher-quality option only after the phone has enough storage, RAM, and thermal headroom.
- Download the default model from CAST's Model setup while on Wi-Fi.
- CAST v63 keeps the screen awake during setup. Keep CAST open in the foreground until the download and verification finish.
- If you already downloaded the approved `.litertlm` artifact, save it in Android Downloads.
- Open CAST.
- Open Model setup if the model is missing.
- Tap Import model file and choose the `.litertlm` file from Downloads.
- If the model download fails, check free storage, reconnect Wi-Fi, then retry before importing manually.
- Send a short test problem and confirm the app no longer says the local model is missing.
If it still will not download or install
- Make sure the tester is on Android, not iPhone.
- Use Chrome if Samsung Internet or another browser is acting strange.
- Delete duplicate failed downloads so they do not tap the wrong old file.
- Check storage. CAST needs room for the APK plus the local model download.
- Uninstall any older CAST beta before installing v63.
- Restart the phone and try the download one more time.
- If it still fails, send a screenshot of the exact Android message and the phone model.
Permissions
No sensor permission should be required at launch. Camera, mic, location, files, watch, and optional context signals are requested only when the tester taps the related tool or opts in during setup. Private Mode keeps selected sessions out of durable memory.
Rocket watch toolbox
The watch is optional. It should send approved capture/control events to the phone. It should not run the main conversational model.