app_hook

This tool on every surface: CLI · MCP · Python · JavaScript · Go · Java · .NET

Call a hook the app registered with Mobium's gray-box library, by name, and return what it answered — sign in, seed data, raise a toast: state set up without walking the UI. Needs the app launched with gray_box. The call is written into a field the library adds only in a gray-box launch and the answer read from the device log; it waits for the app to be idle first, and a hook's own work counts as busy. On iOS the call is typed, about 16 ms a character. An unknown name is refused, naming the hooks the app registered; a hook that throws is reported with its message.

Changes the device, the app or the session: readOnlyHint is false.

Arguments

Name	Type	Required	What it is
args	array of string		Arguments for the hook, as strings, in order
device	string		Device serial to target, e.g. "emulator-5554". Omit when only one device is running.
driver	string: uiautomator2, uiautomator, wda		Driver to use: "uiautomator2" (default for Android; fast, installs a server APK on first use), "uiautomator" (Android, installs nothing, slower, cannot type), or "wda" (WebDriverAgent: iOS simulators and iPhones).
hook	string	yes	The hook's name, as the app registered it ("signIn")
timeout_ms	integer		How long to wait for the app's answer (default 15000)

Examples

Each is the arguments of a tools/call request; the first is shown whole.

Call a hook the app registered, and get back what it answered

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "app_hook",
    "arguments": {
      "hook": "raiseToast",
      "args": [
        "Toast raised by test script"
      ]
    }
  }
}

On an Android 15 emulator the answer's text was:

hook raiseToast answered: "shown"
gray box: the app was idle

mobium hook raiseToast "Toast raised by test script" on MobiumApp, Android 15 emulator, launched with --gray-box: the app's own toast says what the hook was sent