/**
 * Utility to extract OAuth error details from oauth4webapi errors.
 *
 * oauth4webapi's `parseOAuthResponseErrorBody()` only parses error bodies for
 * HTTP 4xx responses (producing `ResponseBodyError` with `.error` and
 * `.error_description`). For 5xx responses (e.g., when Auth0 Actions use
 * `api.access.deny()`), it throws `OperationProcessingError` with the raw
 * `Response` as `.cause`, losing the structured error information.
 *
 * This helper recovers those details by checking:
 * 1. If the error already has `.error` (ResponseBodyError from 4xx) → use directly
 * 2. If `.cause` is a `Response` (OperationProcessingError from 5xx) → parse JSON body
 * 3. Otherwise → return empty object
 *
 * See: https://github.com/auth0/nextjs-auth0/issues/2512
 */
export interface OAuthErrorDetails {
    error?: string;
    error_description?: string;
}
/**
 * Extract `error` and `error_description` from an oauth4webapi error,
 * handling both 4xx `ResponseBodyError` and 5xx `OperationProcessingError`.
 *
 * Returns `{}` (empty `OAuthErrorDetails`) when the error structure is
 * unrecognized or the 5xx response body is not JSON / lacks error fields.
 * Callers should guard with `if (oauthErr.error)` before using the result.
 */
export declare function extractOAuthErrorDetails(err: unknown): Promise<OAuthErrorDetails>;