must be specified when not using one_of - error on structured output using zod on google provider

[cloudycotton]

Description

{
  "error": {
    "code": 400,
    "message": "* GenerateContentRequest.generation_config.response_schema.properties[evening_routines].items.type: must be specified when not using one_of\n",
    "status": "INVALID_ARGUMENT"
  }
}

This is the error I get when I try to stream a structured response using the schema below on google-experimental-1206 model.

Code example

export const Product = z.object({
  name: z.string(),
  category: z.string(),
  description: z.string(),
  key_ingredients: z.string(),
  usage_instructions: z.string(),
  precautions: z.string(),
});

export const Prescription = z.object({
  morning_routines: z.array(Product),
  evening_routines: z.array(Product),
  lifestyle_changes: z.array(z.string()),
  treatment_notes: z.string(),
});

AI provider

^4.0.20 and 1.0.10 for google provider.

const response = await streamObject({
      model: google("gemini-exp-1206"),
      messages: [], // removed for brevity
      schema: Prescription,
    });

|

Additional context

No response

[shaper]

Hi there, we are looking into this, thanks for raising.

In the immediate term as a workaround, it looks like if you define separate schemas for Morning and Evening products (even if the definition is the same) it will fix the issue.

  // Define separate Product schemas for morning and evening routines
  const MorningProduct = z.object({
    name: z.string(),
    category: z.string(),
    description: z.string(),
    key_ingredients: z.string(),
    usage_instructions: z.string(),
    precautions: z.string(),
  });

  const EveningProduct = z.object({
    name: z.string(),
    category: z.string(),
    description: z.string(),
    key_ingredients: z.string(),
    usage_instructions: z.string(),
    precautions: z.string(),
  });

  const Prescription = z.object({
    morning_routines: z.array(MorningProduct),
    evening_routines: z.array(EveningProduct),
    lifestyle_changes: z.array(z.string()),
    treatment_notes: z.string(),
  });

Another workaround is to disable structured outputs:

    model: google('gemini-exp-1206', {
      structuredOutputs: false,
    }),