import type { ONICheckpoint, ONICheckpointer, CheckpointListOptions } from "./types.js";
export declare class MemoryCheckpointer<S> implements ONICheckpointer<S> {
    private store;
    get(threadId: string): Promise<ONICheckpoint<S> | null>;
    put(checkpoint: ONICheckpoint<S>): Promise<void>;
    list(threadId: string, opts?: CheckpointListOptions): Promise<ONICheckpoint<S>[]>;
    delete(threadId: string): Promise<void>;
    getAt(threadId: string, step: number): Promise<ONICheckpoint<S> | null>;
    /** Clone a thread's history up to `step` under a new threadId */
    fork(sourceThreadId: string, step: number, newThreadId: string): Promise<boolean>;
    clear(): void;
}
export declare class NoopCheckpointer<S> implements ONICheckpointer<S> {
    get(_: string): Promise<null>;
    put(_: ONICheckpoint<S>): Promise<void>;
    list(_: string): Promise<ONICheckpoint<S>[]>;
    delete(_: string): Promise<void>;
}
export declare abstract class PersistentCheckpointer<S> implements ONICheckpointer<S> {
    abstract get(threadId: string): Promise<ONICheckpoint<S> | null>;
    abstract put(checkpoint: ONICheckpoint<S>): Promise<void>;
    abstract list(threadId: string, opts?: CheckpointListOptions): Promise<ONICheckpoint<S>[]>;
    abstract delete(threadId: string): Promise<void>;
    getAt(threadId: string, step: number): Promise<ONICheckpoint<S> | null>;
    fork(source: string, step: number, dest: string): Promise<boolean>;
}
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