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Mobster reads an Android screen through adb and uiautomator, maps it to the same accessibility tree an iPhone gives, and acts with adb shell input. Android is experimental: it stays off until you set MOBSTER_EXPERIMENTAL_ANDROID=1. A check you wrote for iOS runs on Android with the same expect assertions. Android runs launch-only and key-less checks today; Smart steps on Android aren’t measured yet.

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Set up

You need the Android SDK with platform-tools. For emulators you also need the Android Emulator and one virtual device (AVD). Android Studio installs all of it, about 3 GB. Mobster doesn’t install the SDK.
mobster sim doctor adds these rows when the flag is on: Android SDK, adb, Android emulator, Android virtual device, Hardware acceleration and Android devices. Each failing row prints the fix. Mobster finds the SDK at $ANDROID_HOME, $ANDROID_SDK_ROOT, then ~/Library/Android/sdk. On a USB phone, turn on Developer options, then USB debugging, plug the phone in and accept the prompt on its screen. A phone that shows unauthorized in adb devices -l is never used.

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Emulators

Mobster boots an emulator with -no-window -no-audio, one run at a time per device. MOBSTER_MAX_SIMS (default 2) caps the emulators Mobster boots. shutdown stops only emulators Mobster booted that aren’t running a check; emulators and phones you started yourself are never stopped.

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Run a check

Checks run on Android emulators only. A USB Android phone ends the check as couldn’t-run before anything is launched, because Mobster can’t yet tell your own builds from the other apps on a phone. A check also runs on Android without the flag when app.path ends in .apk or runtime starts with Android. device: Pixel 9 and runtime: Android 16 pick the AVD whose name starts with the device and whose system image is that release. app.path takes an .apk (Mobster reads its package name with aapt2 from the SDK’s build-tools); app.bundle takes an installed package. Apps that ship with Android (com.android.*, com.google.android.*) keep their data; others reset like on iOS: reinstall for an .apk, data (pm clear) otherwise. Fixtures that seed files, the keychain or the pasteboard, and launch.args and launch.env, make a check couldn’t-run on Android. In a coding agent, list_devices lists Android devices with "platform": "android" (iOS rows say "ios"), verify_start takes one as device, and run_tests takes android. An emulator is treated like a simulator. A USB phone is treated like an iPhone: mobster mcp --allow-device must name it, app_path and resets are refused, and Mobster never clears, reinstalls or changes the permissions of an app on it. Driving a device directly with tap and screen isn’t available on Android yet.

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What works

The tree maps resource-id to the id, text and content-desc to the label, and sizes to dp, so id:, label: and role: selectors read the same on both platforms.

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What doesn’t

  • Typing takes plain ASCII without %. Accents and emoji are refused, not mangled.
  • No push notifications.
  • The tree comes from uiautomator dump, not the Appium UIAutomator2 server. A dump is slower and a screen that animates forever can’t be dumped. The server’s APKs need a pinned download, which mobster sim doctor --fix will do once they are pinned.
  • System permission dialogs aren’t answered yet; grant the permission with conditions.permissions.
  • Crash evidence from logcat isn’t attached to a report yet.
  • Video and the Mac app’s device list aren’t wired.
  • Checks on a USB Android phone are refused (decided 25 Oct 2026). They stay refused until Mobster can tell your own builds from the other apps on a phone. The device tools still reach a phone that mobster mcp --allow-device names.

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Measured

24 Oct 2026, Apple silicon Mac under load 10, Android Studio’s Pixel_8 emulator (API 34, arm64), Settings: The dump time is high because the Mac was busy; measure again on a quiet one before you plan around it.