import type { DurableSessionState } from "#execution/durable-session-store.js";
import type { HarnessModelMessage } from "#harness/messages.js";
import { type ValueDelta } from "#shared/value-delta.js";
/**
 * The durable values a session workflow threads through its steps. `history`
 * is separate from `sessionState` so that only the steps that read or change
 * it receive it as input.
 */
export interface SessionStateValues {
    readonly serializedContext: Record<string, unknown>;
    readonly sessionState: DurableSessionState;
    readonly history: HarnessModelMessage[];
}
/** How a step changed the session's values; an absent value is unchanged. */
export interface SessionStateDelta {
    readonly serializedContext?: ValueDelta;
    readonly sessionState?: ValueDelta;
    readonly history?: ValueDelta;
}
/** A step result the session workflow adopts through its state cursor. */
export interface SessionStateTransition {
    readonly stateDelta: SessionStateDelta;
}
/** `T` with its session values replaced by the delta that produces them. */
export type WithSessionStateDelta<T> = T extends unknown ? Omit<T, keyof SessionStateValues> & SessionStateTransition : never;
/**
 * Runs a session step's work and returns its result with the session values
 * it produced replaced by their delta from the values the step was given.
 *
 * Workflow replay reads every step's output but no step's input, so a step
 * that returns only what changed keeps both replay and storage from carrying
 * the whole session once per step. The workflow body applies the delta to the
 * values it passed in; see {@link applySessionStateDelta}.
 *
 * The input is snapshotted before `work` runs because step code may edit it
 * in place, as a channel adapter does with its state.
 */
export declare function withSessionStateDelta<I extends Partial<SessionStateValues>, R extends Partial<SessionStateValues>>(input: I, work: (input: I) => Promise<R>): Promise<WithSessionStateDelta<R>>;
/** Applies a step's delta to the values that step was given. */
export declare function applySessionStateDelta(values: SessionStateValues, delta: SessionStateDelta): SessionStateValues;