Unified tool surface

All interaction tools below accept a udid parameter and auto-dispatch iOS vs Android based on its shape (UUID → iOS simulator, anything else → Android adb serial). You use the same tool names on both platforms.

For platform-specific caveats (Metro adb reverse, locked-screen describe errors, etc.), see § 9 Platform-specific notes at the bottom.

1. Before You Start

If you delegate simulator tasks to sub-agents, make sure they have MCP permissions.

Use list-devices to get a target id. Results are tagged with platform (ios or android); booted/ready devices come first. Pick the first entry that matches the platform you need — if none are ready, call boot-device with udid (iOS) or avdName (Android). See argent-ios-simulator-setup / argent-android-emulator-setup for full setup flow.

Load tool schemas before first use. Gesture tools (gesture-tap, gesture-swipe, gesture-pinch, gesture-rotate, gesture-custom) may be deferred — their parameter schemas are not loaded until fetched. Always use ToolSearch to load the schemas of all gesture tools you plan to use before calling any of them. If you skip this step, parameters may be coerced to strings instead of numbers, causing validation errors.

2. Best Practices

1. Always refer to tapping_rule from your argent.md rule before tapping.
2. Before performing interactions, consider whether they can be dispatched sequentially - more on that in run-sequence.
3. Use gesture-swipe for lists/scrolling, not gesture-custom, unless you need non-linear movement. Consider whether you need multiple swipes, if yes - use run-sequence.
4. Tap a text field before typing — on iOS try paste first then fall back to keyboard; on Android use keyboard directly (paste is iOS-only).
5. Coordinates are normalized — always 0.0–1.0, not pixels.
6. For native iOS app navigation, prefer describe first. It works on any screen without app restart. Do not navigate from screenshots on regular in-app screens unless describe failed to expose a reliable target. Use native-describe-screen only when you need app-scoped UIKit properties.

3. Opening Apps

Never navigate to an app by tapping home-screen icons. Use launch-app or open-url — they are instant and reliable.

launch-app — by bundle ID

{ "udid": "<UDID>", "bundleId": "com.apple.MobileSMS" }

Common IDs: com.apple.MobileSMS (Messages), com.apple.mobilesafari (Safari), com.apple.Preferences (Settings), com.apple.Maps, com.apple.Photos, com.apple.mobilemail, com.apple.mobilenotes, com.apple.MobileAddressBook (Contacts)

open-url — by URL scheme

{ "udid": "<UDID>", "url": "messages://" }

Common schemes: messages://, settings://, maps://?q=<query>, tel://<number>, mailto:<address>, https://... (Safari)

4. Choosing the Right Tool

5. Finding Tap Targets

IMPORTANT. When moved to a different screen after an action or do not know the coordinates of component, always perform proper discovery first.

Point follow-up native diagnostics after you already have a candidate point:

• native-user-interactable-view-at-point: deepest native view that would receive touch at a known raw iOS point; requires bundleId
• native-view-at-point: deepest visible native view at a known raw iOS point; requires bundleId

If describe Fails

Read the exact error and choose the action that matches it:

• Error mentions ax-service not available or daemon startup failure: the ax-service daemon could not start. Check that the simulator is booted. Use screenshot as a temporary fallback, or use native-describe-screen with an explicit bundleId if the app has native devtools injected.
• describe returns an empty element list: the screen may be blank, loading, or showing content without accessibility labels. Use screenshot to see what is visible, then retry after the content has loaded.
• describe succeeds but is not detailed enough for a React Native app: use debugger-component-tree next.
• You need app-scoped inspection with full UIKit properties (accessibilityIdentifier, viewClassName): use native-describe-screen with an explicit bundleId. This requires native devtools (dylib) injection — call restart-app first if needed.
• You already have a candidate point and want to confirm what would actually receive touch: use native-user-interactable-view-at-point. Use native-view-at-point when you want the visually deepest view instead of the hit-test target.

6. Tool Usage

gesture-tap — Single tap at a point

{ "udid": "<UDID>", "x": 0.5, "y": 0.5 }

Coordinates: 0.0 = left/top, 1.0 = right/bottom.

Before tapping near the bottom of the screen in React Native apps, check that "Open Debugger to View Warnings" banners are not visible — tapping them breaks the debugger connection. Close them with the X icon if present.

gesture-swipe — Straight-line gesture

{ "udid": "<UDID>", "fromX": 0.5, "fromY": 0.7, "toX": 0.5, "toY": 0.3 }

Swipe up (fromY > toY) = scroll content down. Default duration: 300ms. Optional: "durationMs": 500 for slower swipe.

gesture-pinch — Two-finger pinch

{ "udid": "<UDID>", "centerX": 0.5, "centerY": 0.5, "startDistance": 0.2, "endDistance": 0.6 }

All values are normalized 0.0–1.0 (fractions of screen, not pixels) — same as all other gesture tools. startDistance: 0.2 means fingers start 20% of the screen apart; endDistance: 0.6 means they end 60% apart. startDistance < endDistance = pinch out (zoom in). startDistance > endDistance = pinch in (zoom out). Defaults: angle: 0 (horizontal), durationMs: 300. Optional: "angle": 90 for vertical axis, "durationMs": 500 for slower pinch.

gesture-rotate — Two-finger rotation

{
  "udid": "<UDID>",
  "centerX": 0.5,
  "centerY": 0.5,
  "radius": 0.15,
  "startAngle": 0,
  "endAngle": 90
}

All positions and radius are normalized 0.0–1.0 (fractions of screen, not pixels). radius: 0.15 means each finger is 15% of the screen away from center. endAngle > startAngle = clockwise. Default duration: 300ms. Optional: "durationMs": 500 for slower rotation.

gesture-custom — Custom touch sequence

For long-press, drag-and-drop, and other complex sequences, see references/gesture-examples.md. Set "interpolate": 10 to auto-generate smooth intermediate Move events between keyframes.

button — Hardware button press

{ "udid": "<UDID>", "button": "home" }

Values: home, back, power, volumeUp, volumeDown, appSwitch, actionButton

paste — Type text into focused field (iOS only)

{ "udid": "<UDID>", "text": "Hello, world!" }

Tap the field first, then paste. Fall back to keyboard if it doesn't work. On Android the call is rejected by the capability gate ("Tool 'paste' is not supported on android") — use keyboard directly.

keyboard — Type text or press special keys

{ "udid": "<UDID>", "text": "search query", "key": "enter" }

Special keys: enter, escape, backspace, tab, space, arrow-up, arrow-down, arrow-left, arrow-right, f1–f12. Optional: "delayMs": 100 between keystrokes (default 50ms).

rotate — Change orientation

{ "udid": "<UDID>", "orientation": "LandscapeLeft" }

Values: Portrait, LandscapeLeft, LandscapeRight, PortraitUpsideDown

7. Screenshots

Use the explicit screenshot tool only when:

• You need the initial screen state before any action.
• The auto-attached screenshot shows a transitional or loading frame.
• You require extra context.
• You want to check state after a delay (e.g. waiting for a network response).
• A permission dialog, system alert, or native modal overlay is visible and describe did not expose reliable targets.

When using screenshot for permission or native modal navigation:

• Do not switch to screenshot-driven navigation just because a modal is visible. On regular app screens and in-app modals, keep using describe.
• Prefer obvious, centered alert buttons such as Allow, OK, Don't Allow, Not Now, or Continue.
• Tap one control at a time and inspect the returned auto-screenshot before doing anything else.
• After the modal is dismissed, return to normal discovery with describe, native-describe-screen, or debugger-component-tree.

Optional rotation parameter: { "udid": "<UDID>", "rotation": "LandscapeLeft" } — rotates the capture without changing simulator orientation.

Screenshots are downscaled by default (30% of original resolution) to reduce context size. scale accepts values from 0.01 to 1.0. If UI elements are hard to read or you need to inspect fine detail, pass scale: 1.0 to get full resolution: { "udid": "<UDID>", "scale": 1.0 }.

Troubleshooting

8. Action Sequencing with run-sequence

Use run-sequence to batch multiple interaction steps into a single tool call. Only one screenshot is returned — after all steps complete. Use cases: scrolling multiple times, typing and submitting automatically, known sequence of multiple taps, rotating device back and forth.

Do not use run-sequence when any step depends on observing the result of a previous step

Use cases

Use the sequencing when:

• Knowing that some action needs multiple steps without necessarily immediate insight of screenshot
• "scroll to bottom", "scroll to top", "scroll to do X" -> sequence scroll 3-5 times
• form interactions, "clear and retype field" -> you may use triple-tap to select all, type new value
• "submit form" → fill all fields in sequence, tap submit
• "go back to X" → defined tap sequence for the navigation

Allowed tools inside run-sequence

gesture-tap, gesture-swipe, gesture-custom, gesture-pinch, gesture-rotate, button, keyboard, rotate

The udid is shared — do not include it in each step's args. Optional delayMs per step (default 100ms).

Examples

Scroll down three times:

{
  "udid": "<UDID>",
  "steps": [
    { "tool": "gesture-swipe", "args": { "fromX": 0.5, "fromY": 0.7, "toX": 0.5, "toY": 0.3 } },
    { "tool": "gesture-swipe", "args": { "fromX": 0.5, "fromY": 0.7, "toX": 0.5, "toY": 0.3 } },
    { "tool": "gesture-swipe", "args": { "fromX": 0.5, "fromY": 0.7, "toX": 0.5, "toY": 0.3 } }
  ]
}

Type into a focused field and submit:

{
  "udid": "<UDID>",
  "steps": [
    { "tool": "keyboard", "args": { "text": "hello world" } },
    { "tool": "keyboard", "args": { "key": "enter" } }
  ]
}

Tap a known button, then scroll down:

{
  "udid": "<UDID>",
  "steps": [
    { "tool": "gesture-tap", "args": { "x": 0.5, "y": 0.15 } },
    {
      "tool": "gesture-swipe",
      "args": { "fromX": 0.5, "fromY": 0.7, "toX": 0.5, "toY": 0.3 },
      "delayMs": 300
    }
  ]
}

Stops on the first error and returns partial results.

9. Platform-specific notes

Android

• Metro reachability: run adb reverse tcp:8081 tcp:8081 on the device before the RN app starts, or Metro won't be reachable from the device. See argent-metro-debugger for the full workflow. Re-run if the device restarts.
• First-launch permission prompts: reinstall-app on Android always installs with -g so runtime permissions are pre-granted on first launch — no flag to pass.
• Locked screen / secure surfaces: describe throws a clear error if it can't capture (keyguard, DRM, Play Integrity). Unlock the device or fall back to screenshot.
• APK vs .app in reinstall-app: pass .apk absolute path on Android; .app directory on iOS.

iOS

(no iOS-only gotchas collected here yet — add them as they come up)