/**
 * Server-suggested retry delay extraction. Merges the patterns historically used
 * by the OpenAI code provider and Google Gemini retry helpers.
 *
 * Header sources (checked in order):
 *  - `Retry-After` (numeric seconds, or HTTP date)
 *  - `x-ratelimit-reset` (Unix epoch seconds)
 *  - `x-ratelimit-reset-after` (seconds)
 *
 * Body patterns:
 *  - `Your quota will reset after 18h31m10s` / `10m15s` / `39s`
 *  - `Please retry in 250ms` / `Please retry in 12s`
 *  - `"retryDelay": "34.074824224s"` (JSON error detail field)
 *  - `try again in 250ms` / `try again in 12s` / `try again in 12sec`
 *
 * Returns `undefined` if no signal is found.
 */
export declare function extractRetryHint(source: Response | Headers | null | undefined, body?: string): number | undefined;
export interface FetchWithRetryOptions extends RequestInit {
    /** Total fetch attempts (initial + retries). Default `5`. */
    maxAttempts?: number;
    /**
     * Per-delay cap. Server-provided `Retry-After` hints exceeding this return
     * the current response immediately — caller deals with the `!response.ok`.
     * Scheduled values are also capped at the platform timer ceiling. Default
     * `60_000`.
     */
    maxDelayMs?: number;
    /**
     * Fallback delay schedule when no server hint is present. Number, array
     * (indexed by attempt, clamped to last), or function. Default exponential
     * `500ms * 2 ** attempt` capped at `maxDelayMs` and the platform timer
     * ceiling. Values that remain negative or non-finite after capping retry
     * immediately.
     */
    defaultDelayMs?: number | readonly number[] | ((attempt: number) => number);
    /**
     * Optional per-attempt overlay merged into the base `RequestInit` each try.
     * Headers from the overlay shallow-merge over the base. Useful for auth
     * token refresh or user-agent rotation.
     */
    prepareInit?: (attempt: number) => RequestInit | Promise<RequestInit>;
    /**
     * Optional `fetch` implementation override. Defaults to `globalThis.fetch`.
     * Useful for routing requests through a proxy, instrumented transport, or
     * mock during tests.
     */
    fetch?: (input: string | URL | Request, init?: RequestInit) => Promise<Response>;
}
/**
 * Fetch with bounded retries and sensible defaults. Retries on any
 * `isRetryableStatus` (5xx, 408, 429) and on transient network errors. Server
 * `Retry-After`/quota hints are honoured up to `maxDelayMs`; a hint that exceeds
 * the cap returns the current response so the caller can fail fast. Aborts on
 * `init.signal` propagate as `"Request was aborted"`.
 *
 * The caller is responsible for inspecting `!response.ok` once the call returns.
 */
export declare function fetchWithRetry(url: string | URL | ((attempt: number) => string | URL), options?: FetchWithRetryOptions): Promise<Response>;
/**
 * Inspect an arbitrary error value (or its `cause` chain, up to depth 2) for an
 * HTTP status code. Reads `status`, `statusCode`, and `response.status` fields,
 * coerces string values, and falls back to scanning the error message for
 * common patterns like `Error: 401`, `error (429)`, or `HTTP 503`.
 */
export declare function extractHttpStatusFromError(error: unknown): number | undefined;
/**
 * `true` if the given HTTP status code is one we treat as transient: 408
 * (Request Timeout), 429 (Too Many Requests), or any 5xx (server error).
 */
export declare function isRetryableStatus(status: number): boolean;
/**
 * `true` if the message describes an unexpected socket closure — Bun and some
 * proxies surface these for any HTTP/2 stream reset.
 */
export declare function isUnexpectedSocketCloseMessage(message: string): boolean;
/**
 * Identify errors that should be retried: aborts/timeouts in the error name or
 * message, retryable HTTP statuses (see `isRetryableStatus`), unexpected socket
 * closes, and the standard transient phrases. 4xx statuses other than 408/429
 * and validation-shaped messages short-circuit to `false`.
 */
export declare function isRetryableError(error: unknown): boolean;