/** `assets` fetches one built file by its path under /admin (`index.html`, `assets/app.js`); a 404 means missing. */
/** `authBasePath`: the Better Auth instance Admin signs in with, when it is not the default `/api/auth` (e.g. a staff instance). */
export declare function adminShell(request: Request, assets: (path: string) => Response | Promise<Response>, options?: {
    readonly authBasePath?: string;
}): Promise<Response | undefined>;