Drive the device in a tight launch → observe → act → re-observe loop until the goal is reached. Prefer android layout for structured UI. Use screenshot mode whenever it is faster or more reliable.

If multiple devices are connected, get the serial with adb devices -l. Pass --device=<serial> to android ... and -s <serial> to adb ....

1. Launch

URL in a browser: adb -s <serial> shell am start -a android.intent.action.VIEW -d '<url>'
Already-installed app: adb -s <serial> shell monkey -p <pkg> -c android.intent.category.LAUNCHER 1
APK file: android run --apks=<path> --device=<serial> [--activity=<name>]

2. Observe with `android layout`

android layout --device=<serial> --pretty --output=/tmp/ui.json

Match targets by text, content-desc, or resource-id. Use the node's center as tap coordinates.

Re-observe after each action with the mode you chose. android layout --device=<serial> --diff is useful when you only need to see what changed.

3. Use screenshot mode when visual targeting is easier

Screenshot mode is often the better choice for:

WebView or browser page content
Icon-only custom views
Canvas, map, or game surfaces
Any screen where layout is noisy, incomplete, or slower to interpret than the image

android screen capture --output=/tmp/ui.png --annotate
android screen resolve --screenshot=/tmp/ui.png --string="input tap #N"

Labels are valid only for that screenshot. Capture again after every UI change.

4. Act with `adb shell input`

adb -s <serial> shell input tap <x> <y>
adb -s <serial> shell input text '<text-with-%s-for-spaces>'
adb -s <serial> shell input swipe <x1> <y1> <x2> <y2> <ms>
adb -s <serial> shell input keyevent <KEYCODE>

Example: adb -s <serial> shell input text 'hello%sworld'

Rules

Re-observe after every action. Coordinates and screenshot labels go stale immediately.
Clear blockers first: permission dialogs, onboarding sheets, update prompts.
Use the observation mode that is clearer: layout for structured UI, screenshot for visual UI.

Notes

Don't type URLs into the address bar. Open them with am start -a VIEW -d '<url>'.
If the foreground app is unclear, check it with adb -s <serial> shell dumpsys window | rg 'mCurrentFocus|mFocusedApp'.

android-cli-ui-automation-skill