useAppFunctions

Source: packages/sdk/src/hardware/useAppFunctions.ts

Bridges Android 16/17 (API 36+) AppFunctions subsystem. AppFunctions allows system AI (Gemini Assistant) and local agentic frameworks to discover, inspect, and invoke on-device actions directly within your application.

Verified on Pixel 11 Pro (grizzly): bound directly to android.app.appfunctions.IAppFunctionManager (system service 133). Nothing is simulated: when the system service is active, source is 'hardware'.

Built-in Hardware Functions

Every installation pre-registers core silicon actions:

1. check_phone_thermals: Queries Tensor G6 silicon thermal headroom, thermal status, and CPU core cluster load via ADPF.
2. purge_memory_cache: Requests an explicit Android Runtime (ART) garbage collection pass and reports freed heap memory.
3. get_device_silicon_info: Returns SoC model, GPU renderer, and confirmed hardware feature flags.

Custom AppFunctions

Developers can declare custom schemas and handlers dynamically with registerFunction(schema, handler). When Gemini or a local workflow invokes that function ID, executeFunction dispatches to your handler and tracks execution latency in milliseconds.

Signature

function useAppFunctions(): {
  isSupported: boolean;
  serviceFound: boolean;
  apiLevel: number | null;
  serviceName: string | null;
  functions: AppFunctionSchema[];
  error: string | null;
  source: TelemetrySource;
  refresh: () => void;
  executeFunction: (functionId: string, params?: Record<string, any>) => Promise<AppFunctionExecutionResult>;
  registerFunction: (schema: AppFunctionSchema, handler: (params: Record<string, any>) => Promise<any> | any) => void;
  unregisterFunction: (functionId: string) => boolean;
};

Outputs

Field	Type	Unit	Description
isSupported	boolean	flag	true if device runs Android 16 QPR / Android 17 (API 36+).
serviceFound	boolean	flag	true if android.app.appfunctions.IAppFunctionManager system service was discovered.
apiLevel	number | null	int	Device Android API level (37 on Pixel 11 Pro).
serviceName	string | null	name	System service name ('app_function').
functions	AppFunctionSchema[]	array	All available AppFunction schemas (built-in hardware + custom registered).
error	string | null	text	Latest execution or query error message.
source	TelemetrySource	enum	'hardware' when backed by real system service, 'unavailable' on older OS or emulators.

Functions

Function	Inputs	Returns	Description
executeFunction(functionId, params?)	functionId: string. params?: Record<string, any>.	Promise<AppFunctionExecutionResult>	Executes a function by ID and measures execution time in ms.
registerFunction(schema, handler)	schema: AppFunctionSchema. handler: (params) => any.	void	Registers a custom function handler callable by Gemini or local agents.
unregisterFunction(functionId)	functionId: string	boolean	Removes a registered custom function handler.
refresh()	none	void	Re-queries the Android app_function system service.

Example

import { View, Text, Button } from 'react-native';
import { useAppFunctions } from '@pixelkit-labs/sdk';

export function GeminiAppFunctionsCard() {
  const { isSupported, serviceFound, functions, executeFunction } = useAppFunctions();

  const runThermals = async () => {
    const result = await executeFunction('check_phone_thermals');
    console.log('Thermal result:', result.data);
  };

  return (
    <View>
      <Text>AppFunctions: {serviceFound ? 'Active (API 37)' : 'Unavailable'}</Text>
      <Text>Registered Tools: {functions.length}</Text>
      <Button title="Check Thermals via Assistant" onPress={runThermals} />
    </View>
  );
}