import type { Api, AssistantMessage, Model } from "../types.js";
/**
 * Create the initial empty assistant message that a streaming response builds
 * upon: no content yet, the model's api/provider/id copied across, zeroed
 * usage counters, a placeholder `stop` reason, and a timestamp of now. Each
 * provider fills it in as events come through.
 */
export declare function createAssistantMessageOutput<TApi extends Api>(model: Model<TApi>): AssistantMessage;
