/**
 * Record that a memory was retrieved. Bumps `count` and `lastUsedMs`. Cheap
 * enough to call on every recall hit.
 */
export declare function bumpMemoryAccess(memoryId: string): Promise<void>;
/**
 * Compute retention in [MIN_RETENTION, 1] for a memory given its capture
 * time. Memories with more recorded accesses decay slower (longer effective
 * half-life). Memories never accessed start at 1 and decay normally.
 */
export declare function computeRetention(params: {
    memoryId: string;
    capturedAtMs: number;
    nowMs?: number;
}): Promise<number>;
/**
 * Score a list of memory candidates by retention. Lower retention =
 * more likely to be filtered out by recall. The caller decides the
 * cutoff; this just computes the scores.
 */
export declare function scoreMemoriesByRetention(candidates: ReadonlyArray<{
    id: string;
    capturedAtMs: number;
}>, nowMs?: number): Promise<Array<{
    id: string;
    retention: number;
}>>;
/** Test helper: clear the cache + remove the file. */
export declare function __resetAccessStats(): Promise<void>;