/**
 * Structured ACME protocol error with RFC 8555 fields.
 * Provides type URN, subproblems, Retry-After, and retryability classification.
 */
export declare class AcmeError extends Error {
    readonly status: number;
    readonly type: string;
    readonly detail: string;
    readonly subproblems: Array<{
        type: string;
        detail: string;
        identifier?: {
            type: string;
            value: string;
        };
    }>;
    readonly url: string;
    readonly retryAfter: number;
    constructor(options: {
        message?: string;
        status: number;
        type?: string;
        detail?: string;
        subproblems?: Array<{
            type: string;
            detail: string;
            identifier?: {
                type: string;
                value: string;
            };
        }>;
        url?: string;
        retryAfter?: number;
    });
    /**
     * True for HTTP 429 or ACME rateLimited type URN
     */
    get isRateLimited(): boolean;
    /**
     * True for transient/retryable errors: 429, 503, 5xx, badNonce.
     * False for definitive client errors: 400 (non-badNonce), 403, 404, 409.
     */
    get isRetryable(): boolean;
}