/**
 * Branded type for books
 */
export type string_book = string & {
    readonly __type: 'book';
};
/**
 * Type guard to check if a string is a valid agent source
 *
 * @public exported from `@promptbook/core`
 */
export declare function isValidBook(value: string): value is string_book;
/**
 * Validates and converts a string to agent source branded type
 * This function should be used when you have a string that you know represents agent source
 * but need to convert it to the branded type for type safety
 *
 * Note: [🔂] This function is idempotent.
 *
 * @public exported from `@promptbook/core`
 */
export declare function validateBook(source: string): string_book;
/**
 * Default book
 *
 * @deprecated Use `$generateBookBoilerplate` instead
 *
 * @public exported from `@promptbook/core`
 */
export declare const DEFAULT_BOOK: string_book;