/**
 * Data validation utilities
 */
import type { ChatType } from "../types/index.js";
/**
 * Validate chat structure
 * @param {unknown} chat - Value to validate as chat
 * @returns {boolean} True if value is a valid chat
 */
export declare function isValidChat(chat: unknown): chat is ChatType;
/**
 * Validate non-empty string
 * @param {unknown} value - Value to validate as non-empty string
 * @returns {boolean} True if value is a non-empty string
 */
export declare function isNonEmptyString(value: unknown): value is string;