/**
 * Shared HTTP for engine adapters (M6): POST JSON with exponential backoff on
 * 429/5xx and a timeout. Injectable `httpPost` and `sleep` so retry/backoff
 * paths test without network or real delays.
 */
export interface HttpJsonResponse {
    status: number;
    json(): Promise<unknown>;
    text(): Promise<string>;
}
export type HttpPost = (url: string, init: {
    headers: Record<string, string>;
    body: string;
    signal?: AbortSignal;
}) => Promise<HttpJsonResponse>;
/** A non-2xx HTTP response that is not (or no longer) retryable. */
export declare class HttpError extends Error {
    readonly status: number;
    constructor(status: number, message: string);
}
export interface RetryOptions {
    retries?: number;
    baseDelayMs?: number;
    timeoutMs?: number;
    sleep?: (ms: number) => Promise<void>;
}
/** Real HTTP POST over the global fetch; the default for production use. */
export declare const defaultHttpPost: HttpPost;
export declare function postJsonWithRetry(httpPost: HttpPost, url: string, init: {
    headers: Record<string, string>;
    body: string;
}, opts?: RetryOptions): Promise<unknown>;