/**
 * Error extractor helpers consumed by the
 * `fjall/mask-error-message-at-boundary` ESLint rule by name. Renaming any
 * of `getErrorMessage`, `getErrorStack`, or `formatErrorString` requires a
 * matching update in `cli/eslint-rules/mask-error-message-at-boundary.js`
 * (`ERROR_EXTRACTOR_CALLEES`).
 *
 * Normalise an unknown thrown value into an Error instance.
 */
export declare function normaliseError(error: unknown): Error;
/**
 * Safely extract error message from any error type. Extractor helper —
 * see file-header note. Result MUST be wrapped in `maskSensitiveOutput()`
 * before reaching any logger / state setter / persistence / callback sink.
 */
export declare function getErrorMessage(error: unknown): string;
/**
 * Check if an error has a specific error code
 */
export declare function hasErrorCode(error: unknown, code: string): boolean;
/**
 * Extract error code from an error if present
 */
export declare function getErrorCode(error: unknown): string | undefined;
/**
 * Safely extract the stack trace from an unknown thrown value. Extractor
 * helper — must be `maskSensitiveOutput()`-wrapped at every sink.
 */
export declare function getErrorStack(error: unknown): string | undefined;
/**
 * Create a formatted error string with optional code prefix. Extractor
 * helper — must be `maskSensitiveOutput()`-wrapped at every sink.
 */
export declare function formatErrorString(error: unknown): string;