import type { ChannelSchema, GraphCheckpoint, GraphCheckpointV1, GraphTask, PendingInterrupt, StoredGraphCheckpoint } from '../types/graph.js';
/**
 * Reads a checkpoint in the current schema from one in either schema. A custom checkpointer whose
 * store still holds 1.x checkpoints can return them as they are, since the graph calls this on every
 * read; a tool that reads a store directly calls it too. A version 2 checkpoint is returned as it is.
 *
 * A version 1 checkpoint gains its id, its tasks spelled out from `next` when it carried none, and its
 * questions moved from the single `interrupt` into `interrupts`.
 */
export declare function migrateCheckpoint<S extends ChannelSchema = ChannelSchema>(checkpoint: StoredGraphCheckpoint<S>): GraphCheckpoint<S>;
/** A checkpoint being assembled, before `toCheckpoint()` fills in its id, tasks, and questions. */
export type CheckpointDraft<S extends ChannelSchema = ChannelSchema> = Omit<GraphCheckpoint<S>, 'version' | 'id' | 'tasks' | 'interrupts'> & {
    version?: 2;
    id?: string;
    tasks?: GraphTask[];
    interrupts?: PendingInterrupt[];
};
/**
 * Turns a draft or a stored checkpoint of either schema into one in the current schema. The id is
 * always derived again, so a checkpoint copied to another thread or step never keeps a stale one.
 */
export declare function toCheckpoint<S extends ChannelSchema = ChannelSchema>(draft: CheckpointDraft<S> | GraphCheckpointV1<S>): GraphCheckpoint<S>;