export interface EnsureVercelJsonResult {
    readonly servicePrefix: string;
}
/**
 * Ensure `vercel.json` declares the Nuxt web service and the eve agent
 * service so a Vercel deployment ships both from one project.
 *
 * Existing services are preserved untouched; an already-configured eve
 * service's `routePrefix` wins over {@link input.servicePrefix}. The file is
 * only rewritten when the resulting config differs from what is on disk.
 */
export declare function ensureEveVercelJson(input: {
    readonly appRoot: string;
    readonly eveBuildCommand: string;
    readonly nuxtRoot: string;
    readonly servicePrefix: string;
}): Promise<EnsureVercelJsonResult>;