use-mobile-device

name	use-mobile-device
description	Drive iOS and Android devices using the mobile-device-mcp tools (screenshot, tap, uitree, scroll, type_text, run_code, etc.). Use when MCP device-control tools are available and the user wants to interact with a mobile device.

Using mobile devices

You have MCP tools for controlling iOS and Android devices. This skill covers how to use them effectively.

Interaction loop

1. Call list_devices to get a valid device_id.
2. Call screenshot to see the current screen.
3. Call uitree to get elements with coordinates. Use the search param to filter by text.
4. Act: tap, type_text, scroll, press_button, long_press, double_tap, etc. Use the element's center field as tap coordinates.
5. Call screenshot to confirm the result.

Repeat 2-5 as needed.

Finding elements

uitree returns elements as JSONL. Each line is a JSON object with these fields (all always present):

Field	Type	Description
id	number	Sequential integer starting from 1
text	string	Element text (may be empty)
type	string	Semantic type: button, input, text, switch, image, etc.
bounds	object	{left, top, right, bottom} in screen coordinates
center	object	{x, y} — center of bounds, ready to use as tap coordinates
visible	boolean	Whether the element is within the screen bounds
clickable	boolean	Whether the element accepts taps

• Use search to filter by text (case-insensitive substring match).
• Use limit to cap results when the tree is large.
• If the target element is off-screen, scroll to reveal it, then call uitree again.
• Use center coordinates for tapping, not visual estimation from screenshots.

Coordinates

• Android: pixels.
• iOS: logical points (1x scale). Do not multiply by screen scale.

Text input

Tap the target text field first to focus it, then call type_text.

Scrolling

Scroll direction follows finger movement:

• Down (reveal content below): startY > endY (finger moves up).
• Up (reveal content above): startY < endY (finger moves down).
• Use mid-screen X and a Y delta of 300-500.

Buttons

press_button accepts these values: home, back, volumeUp, volumeDown, enter, dpadUp, dpadDown, dpadLeft, dpadRight, dpadCenter. iOS only supports home.

long_press accepts an optional duration in milliseconds (1–10000, default 500).

Apps

• list_apps returns installed app IDs.
• launch_app and terminate_app take app_id: bundle ID on iOS, package name on Android.

Code Execution

Executes JavaScript on-device. Each call runs in a fresh context — no state persists between calls.

Returns { result: "last expression value", logs: ["console.log output", ...] }.

For detailed run_code API reference per platform, see examples/run-code-tool.md.

Android

Sandboxed JS engine with UIAutomator bindings. Write JavaScript, not Java.

Global objects: uiDevice, By, Until, console.

// Find and click a button by text
var btn = uiDevice.findObject(By.text("Submit"));
btn.click();

// Wait for an element to appear
uiDevice.wait(Until.hasObject(By.res("com.app:id/done")), 5000);

// Screen dimensions — callable functions, not bare properties
var w = uiDevice.displayWidth();
var h = uiDevice.displayHeight();

iOS

JS engine with XCUITest bindings. Write JavaScript, not Swift — use var for declarations, not typed let.

Global objects: app (foreground app), springboard, device, openApp(bundleId), sleep(ms), console.

// Tap a button by label
app.buttons["Login"].tap();

// Type into a text field
var field = app.textFields.firstMatch;
field.tap();
field.typeText("hello");

// Wait for element existence
var ok = app.buttons["OK"].waitForExistence(5);

// Query by predicate
var cells = app.cells.matchingPredicate("label CONTAINS 'Item'");

Avoid

• Guessing coordinates from screenshots instead of reading uitree.
• Assuming an action succeeded without verifying via screenshot.
• Calling tools without a device_id from list_devices.