/** Maximum accepted operations in a sliding duration. */
export interface RateWindowPolicy {
    windowMs: number;
    max: number;
}
/** Admission result, next stored timestamps, and wait before retrying. */
export interface RateWindowDecision {
    allowed: boolean;
    timestamps: number[];
    retryAfterMs: number;
}
/**
 * A sliding rate window; persist timestamps only alongside the accepted operation.
 * @capability rate-window-policy Evaluate deterministic request windows with retry timing.
 */
export declare function decideRateWindow(timestamps: readonly number[], nowMs: number, policy: RateWindowPolicy): RateWindowDecision;