Model seems to ignore `.optional()` fields, and instead uses fasly values such as 0, empty strings etc'

[uriva]

Confirm this is a Node library issue and not an underlying OpenAI API issue

• This is an issue with the Node library

Describe the bug

Model seems to ignore .optional() fields, and instead uses nullary values, empty strings etc'

I'm not sure if it's a library issue or chatgpt model issue.

To Reproduce

I suspect this is a KI or an upstream problem, but let me know if not I'll send a repro

Code snippets

No response

OS

ubuntu

Node version

22.7.0

Library version

4.57.0

[uriva]

According to the docs, the model treats all fields as required, but it is recommended to use a union with null to achieve this: https://platform.openai.com/docs/guides/structured-outputs#all-fields-must-be-required

This sounds like zod's .optional should be interperted like that.

[RobertCraigie]

Thanks for reporting!

This sounds like an issue with the underlying OpenAI API and not the SDK, so I'm going to go ahead and close this issue. When you use .optional() we mark the property as required and then update the schema to mark it as nullable.

Would you mind reposting at community.openai.com?

[jovermier]

This may be the line of code that converts an optional property to required.
propDef.isOptional() && !refs.openaiStrictMode ? acc.required : [...acc.required, propName],

I don't see any code for making the property nullable. In my testing I don't see the output schema nullable either.

[uriva]

also just to be compliant with the zod type, undefined is considerably better if possible.
maybe with something that strips the undefined values after, then the user will be oblivious to all this as they should be.

[silasalberti]

As discussed above, the API doesn't allow optional fields and the docs recommend nullable fields as a workaround. The SDK already supports Zod's .nullable() which achieves this purpose. People might be unaware about that nuance, so I propose adding a warning on .optional() that recommends using .nullable() instead: #1214

(I briefly thought about instead making .optional() have the same behavior as .nullable(). However, as mentioned above that would not be compliant with the Zod type, i.e. zod validation fails if it gets null instead of undefined.)