import { type AgentResponseChunk } from "../agents/agent.js";
import type { ChatModelOutput } from "../agents/chat-model.js";
export declare class ExtractMetadataTransform extends TransformStream<AgentResponseChunk<ChatModelOutput>, AgentResponseChunk<ChatModelOutput & {
    metadata?: string;
}>> {
    private buffer;
    private cursor;
    private state;
    constructor({ start, end, parse, }: {
        start: string;
        end: string;
        parse: (raw: string) => object;
    });
}