Android 17 AppFunctions & System Gemini Assistant

Exposing structured app capabilities to the system Gemini assistant via useAppFunctions.

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Overview

Starting with Android 17 (API 37), Google introduced the AppFunctions architecture (android.app.appsearch.AppFunctionManager). AppFunctions replaces legacy App Actions and static Shortcuts with a dynamic, schema-driven framework that lets AI agents (such as the system-level Gemini Assistant) discover, invoke, and inspect app functionalities at runtime.

The useAppFunctions hook provides full lifecycle management for registering and executing on-device functions.

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

export function AssistantFunctionsList() {
  const { isSupported, isAvailable, functions, executeFunction } = useAppFunctions();

  return (
    <View>
      <Text>AppFunctions Supported: {isSupported ? 'Yes' : 'No'}</Text>
      <Text>System Service Available: {isAvailable ? 'Yes' : 'No'}</Text>

      {functions.map((fn) => (
        <View key={fn.id}>
          <Text style={{ fontWeight: 'bold' }}>{fn.name} ({fn.category})</Text>
          <Text>{fn.description}</Text>
          <TouchableOpacity
            onPress={async () => {
              const result = await executeFunction(fn.id, {});
              console.log('Execution result:', result);
            }}
          >
            <Text>Test Execute</Text>
          </TouchableOpacity>
        </View>
      ))}
    </View>
  );
}

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AppFunctions Architecture

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Security & Permission Model

1. System Assistant Verification: Only authorized system assistant packages holding the EXECUTE_APP_FUNCTIONS signature permission can invoke registered AppFunctions.
2. Parameter Validation: Input and output arguments are strictly validated against the declared JSON Schema before execution begins.
3. Execution Timeouts: Invocations enforce a default 5-second deadline to ensure assistant responsiveness.