Sessions

The Expo layer owns a cross-platform session abstraction. A session keeps conversational state — natively where the provider supports it, emulated where it doesn't.

export type CreateSessionOptions = {
  instructions?: string;
  provider?: ExpoAIProvider;
  fallback?: 'none' | 'cloud' | 'any';
  temperature?: number;
  maxOutputTokens?: number;
  metadata?: Record<string, string>;
};

export type ExpoAISession = {
  id: string;
  provider: ExpoAIProvider;

  generate(options: SessionGenerateOptions): Promise<GenerateResult>;
  stream(options: SessionGenerateOptions): AsyncIterable<GenerateChunk>;
  generateObject<T>(options: SessionGenerateObjectOptions): Promise<T>;

  reset(): Promise<void>;
  dispose(): Promise<void>;
};

const session = await ExpoAI.createSession({
  instructions: 'You are a concise note-taking assistant.',
});
await session.generate({ prompt: 'Capture the action items from this meeting.' });
await session.dispose();

Native mapping

Concept	iOS	Android	Cloud
Session	Native Foundation Models session	Native or emulated session	Conversation / thread
Instructions	Native instructions	Prompt prefix	System message
Streaming	Native if available	Native or emulated	Provider stream
Structured output	Native if available	JSON prompt + validation	JSON mode / tools
Tools	Native if available	Emulated	Provider tools