/**
 * Parses rate limit headers from HTTP responses
 */
export interface RateLimitHeaders {
    limit: number | null;
    remaining: number | null;
    reset: number | null;
}
/**
 * Parsed rate limit headers plus the request context they came from.
 *
 * Delivered to the `onRateLimitInfo` callback after every successful request
 * so callers can build observability around the rate limit (warn at thresholds,
 * emit metrics, etc.).
 */
export interface RateLimitInfo extends RateLimitHeaders {
    /** HTTP method of the call (GET, POST, ...). */
    method: string;
    /** Request URL. */
    url: string;
}
/**
 * Returns the fraction of the rate limit currently used in [0.0, 1.0],
 * or `null` when the headers aren't usable (missing limit, zero limit,
 * missing remaining).
 */
export declare function rateLimitUsagePct(info: RateLimitHeaders): number | null;
/**
 * Extract rate limit information from response headers
 */
export declare function parseRateLimitHeaders(headers: Headers): RateLimitHeaders;
/**
 * Returns a `RateLimitInfo` (headers + request context), or `null` when no
 * `x-ratelimit-*` headers are present (e.g. self-hosted Lago instance with
 * limits disabled). Useful for skipping observability emission entirely when
 * there's nothing to report.
 */
export declare function parseRateLimitInfo(headers: Headers, method: string, url: string): RateLimitInfo | null;