generateVNext with structured output results in undefined object

const result = await agent.generateVNext(inputData.prompt, {
  structuredOutput: {
    schema: z
      .object({
        text: z.string().min(1)
      })
      .array(),
  },
});

const result = await agent.generateVNext(inputData.prompt, {
  structuredOutput: {
    schema: z
      .object({
        text: z.string().min(1)
      })
      .array(),
  },
});