/**
 * Sends delegated task results to their parent and conversation results to
 * the caller of each turn.
 */
import type { TurnCaller } from "#channel/types.js";
import type { RuntimeSubagentChildResult } from "#runtime/actions/types.js";
import type { AgentTurnOutcome } from "#shared/agent-turn-outcome.js";
import type { TokenUsage } from "#shared/token-usage.js";
/**
 * Resumes the parent driver's hook with a delegated subagent result.
 * No-op for root sessions.
 *
 * `usage` — the completed child's session-total token spend — is
 * attached to success results so the caller can attribute the
 * subagent's tokens. Error results never carry usage.
 */
export declare function notifyDelegatedParentStep(input: {
    readonly result: RuntimeSubagentChildResult | undefined;
    readonly serializedContext: Record<string, unknown>;
    readonly usage?: TokenUsage;
}): Promise<void>;
/** Settled turn payload forwarded from the driver to the caller. */
export interface SettledTurnNotification {
    readonly output: unknown;
    readonly isError?: boolean;
    /** Usage this turn added; omitted (zero) on crash and expiry paths. */
    readonly usage?: TokenUsage;
}
/**
 * Sends a settled conversation turn to the caller that started it.
 *
 * `lifecycle` is the child engine's explicit verdict — `parked` when the
 * child session survived the turn and can accept another delivery,
 * `terminal` when it ended with this turn. It is carried on the result as
 * an {@link AgentTurnOutcome} so the caller never infers lifecycle from
 * success or error codes.
 */
export declare function notifyTurnCallerStep(input: {
    readonly caller: TurnCaller | undefined;
    readonly lifecycle: AgentTurnOutcome["kind"];
    readonly sessionId: string;
    readonly settled: SettledTurnNotification;
}): Promise<void>;
/** Resolves the caller that created a delegated conversation session. */
export declare function resolveInitialTurnCallerStep(input: {
    readonly serializedContext: Record<string, unknown>;
}): Promise<TurnCaller | undefined>;