export declare class RateLimitNotifier {
    private lastKey;
    /**
     * Returns the message to post for this turn's rate-limit status, or null to
     * stay silent (already announced for this window, or status is allowed/none).
     */
    decide(userId: string, rateLimit: {
        status: "warning" | "exceeded";
        resetsAt?: number;
    } | undefined): string | null;
}