import { z } from 'zod';
import type { PlanItem } from '../schemas/plan';
declare const ImagePromptResponseSchema: z.ZodObject<{
    prompt: z.ZodString;
}, "strip", z.ZodTypeAny, {
    prompt: string;
}, {
    prompt: string;
}>;
type ImagePromptResponse = z.infer<typeof ImagePromptResponseSchema>;
/**
 * Calls the Gemini API to refine a PlanItem into a detailed image prompt.
 *
 * @param item - The PlanItem containing asset name, bucket, size, context.
 * @param theme - The overall theme.
 * @param apiKey - The Google Generative AI API key (optional).
 * @returns A Promise resolving to an object containing only the prompt string.
 */
export declare function generateImagePrompt(item: PlanItem, theme: string, apiKey?: string): Promise<ImagePromptResponse>;
export {};