/**
 * The subagent id this event came from, or undefined on the main thread. A
 * value the server would reject is hashed rather than dropped, so a surprising
 * host id still yields a stable per-agent identity and never fails the request.
 */
export declare function subagentId(input: {
    agent_id?: unknown;
}): string | undefined;
/** Local state key: the session id, or `${session_id}:agent:${agentId}` in a subagent. */
export declare function hookStateSessionId(input: {
    session_id: string;
    agent_id?: unknown;
}): string;