/** Original diagnostic error and the library's neutral, state-aware display copy. */
export type ErrorMessageFormatter = (error: unknown, defaultMessage: string) => string | undefined;
export declare const ErrorMessageContext: import("react").Context<ErrorMessageFormatter | undefined>;
/** Keep existing Error-typed state while retaining non-Error rejections privately. */
export declare function normalizeError(cause: unknown): Error;
/** Presentation only: callers retain their errors and delivery/retry state. */
export declare function useErrorMessage(): (error: unknown, defaultMessage?: string) => string;