/**
 * Snapshot helpers for agent state capture and restoration.
 *
 * These functions provide the shared implementation for {@link LocalAgent.takeSnapshot}
 * and {@link LocalAgent.loadSnapshot}. Since all `LocalAgent` implementations share the
 * same snapshot logic, these helpers avoid duplication. The canonical public API is
 * `agent.takeSnapshot()` / `agent.loadSnapshot()` — prefer calling those directly.
 */
import type { JSONValue } from '../types/json.js';
import type { LocalAgent } from '../types/agent.js';
import type { Snapshot } from '../types/snapshot.js';
/**
 * All available fields that can be included in a snapshot.
 */
export declare const ALL_SNAPSHOT_FIELDS: readonly ["messages", "state", "systemPrompt", "modelState", "interrupts"];
/**
 * Strongly typed preset definitions for snapshot field selection.
 * This object allows easy evolution of presets and type-safe access.
 */
export declare const SNAPSHOT_PRESETS: {
    readonly session: readonly ["messages", "state", "systemPrompt", "modelState", "interrupts"];
};
/**
 * Preset name for snapshot field selection.
 */
export type SnapshotPreset = keyof typeof SNAPSHOT_PRESETS;
/**
 * Valid snapshot field names.
 */
export type SnapshotField = (typeof ALL_SNAPSHOT_FIELDS)[number];
/**
 * Creates an ISO 8601 timestamp string.
 *
 * @returns Current timestamp in ISO 8601 format
 */
export declare function createTimestamp(): string;
/**
 * Options for taking a snapshot of agent state.
 */
export type TakeSnapshotOptions = {
    /**
     * Preset to use as the starting set of fields.
     * If not specified, starts with an empty set (unless include is specified).
     */
    preset?: SnapshotPreset;
    /**
     * Fields to add to the snapshot.
     * These are added to the preset fields (if any).
     */
    include?: SnapshotField[];
    /**
     * Fields to exclude from the snapshot.
     * Applied after preset and include to filter out specific fields.
     */
    exclude?: SnapshotField[];
    /**
     * Application-owned data to store in the snapshot.
     * Strands does not read or modify this data.
     */
    appData?: Record<string, JSONValue>;
};
/**
 * Shared implementation for {@link LocalAgent.takeSnapshot}.
 * Prefer calling `agent.takeSnapshot(options)` directly.
 *
 * @param agent - The agent to snapshot
 * @param options - Snapshot options
 * @returns A snapshot of the agent's state
 */
export declare function takeSnapshot(agent: LocalAgent, options: TakeSnapshotOptions): Snapshot;
/**
 * Shared implementation for {@link LocalAgent.loadSnapshot}.
 * Prefer calling `agent.loadSnapshot(snapshot)` directly.
 *
 * @param agent - The agent to restore state into
 * @param snapshot - The snapshot to load
 */
export declare function loadSnapshot(agent: LocalAgent, snapshot: Snapshot): void;
/**
 * Resolves snapshot fields based on preset/include/exclude parameters.
 *
 * Order of operations:
 * 1. Start with preset fields (if specified)
 * 2. Add include fields
 * 3. Remove exclude fields
 *
 * @param options - Snapshot options containing preset, include, and exclude fields
 * @returns Set of resolved field names
 * @throws Error if no fields would be included
 */
export declare function resolveSnapshotFields(options?: TakeSnapshotOptions): Set<SnapshotField>;
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