import { type NotebookCheckpointIdentity } from "./checkpoint-format.ts";
export interface NotebookCheckpointActivity {
    touch(): void;
    release(): void;
}
export declare function activateNotebookCheckpoint(identity: NotebookCheckpointIdentity): Promise<NotebookCheckpointActivity>;
export declare function expireNotebookSessionCheckpoints(agentDir: string, retentionAge: () => number | undefined, now?: number): Promise<void>;