@stewmore/expo-ai-android-aicore

Android Gemini Nano via ML Kit GenAI / AICore (on-device) provider for the Expo AI Runtime.

Install & use

import { ExpoAI } from '@stewmore/expo-ai-core';
import '@stewmore/expo-ai-android-aicore'; // registers the Android adapter (side-effect import)

const caps = await ExpoAI.getCapabilities();
if (caps.available && caps.provider === 'android-aicore-gemini-nano') {
  const result = await ExpoAI.generate({ prompt: 'Write a haiku about Kotlin.' });
  console.log(result.text); // privacy: on-device
}

If the model isn't downloaded yet, the availability reason is model_not_downloaded; trigger a download:

import { downloadGeminiNanoModel } from '@stewmore/expo-ai-android-aicore';
await downloadGeminiNanoModel();

Config plugin

The native module autolinks on its own, but add the config plugin so expo prebuild also raises the project's minSdkVersion to the AICore floor (26) — no manual expo-build-properties editing:

{
  "expo": {
    "plugins": ["@stewmore/expo-ai-android-aicore"]
  }
}

Override the floor if your app already targets a higher API:

{
  "expo": {
    "plugins": [["@stewmore/expo-ai-android-aicore", { "minSdkVersion": 31 }]]
  }
}

Requirements

• A device with AICore / Gemini Nano (e.g. recent Pixel and Galaxy flagships), Android API 26+.
• A development build (custom native code — not Expo Go): npx expo prebuild && npx expo run:android.

AICore is system-managed and may still be initializing — the adapter surfaces model_initializing / aicore_unavailable (retryable) so the runtime can fall back per the app's policy.

What it maps

| Runtime | ML Kit GenAI | | -------------------- | ----------------------------------------------------------------------------- | | generate | Prompt API GenerativeModel.generateContent | | stream | generateContentStream (Flow) → token deltas | | capability detection | checkStatus() → FeatureStatus | | model download | download() (downloadGeminiNanoModel) | | sessions | emulated (transcript replayed as prompt prefix — the Prompt API is stateless) | | errors | GenAiException.errorCode → ExpoAIError |

Structured output and summarize/rewrite/proofread are provided by the core runtime over generate (JSON prompt + validate + repair).

The com.google.mlkit:genai-prompt API is beta; bump the dependency version and confirm symbol names against the installed SDK when building.