import { type UnstampedMessageStreamEvent } from "#protocol/message.js";
/** Emits an already-projected task-owned `subagent.called` event on the parent stream. */
export declare function emitTaskSubagentCalledStep(input: {
    readonly event: UnstampedMessageStreamEvent;
    readonly parentWritable: WritableStream<Uint8Array>;
    readonly serializedContext: Record<string, unknown>;
}): Promise<{
    readonly serializedContext: Record<string, unknown>;
}>;