Expand schema DSL to support optional fields

[simonw]

I omitted optional field support in the original design - but that forces the model to hallucinate if a value is unavailable.

[simonw]

One option could be to support a ? at the end of the field name:

name: their name
age? (Int)

Would that mean that the value in the key can be null, or would it mean the key can be omitted entirely?

I prefer nulls and consistently shaped objects, but in JSON schema I believe not having something in the required field means the key can be missing - a nullable property (is that widely supported?) indicates it can be null.

[simonw]

I got ChatGPT Deep Research to research how different providers support JSON Schema: https://chatgpt.com/share/67c690de-d114-8006-9fad-d61122ac9b26

Here's the key information it dug up in a Gist: https://gist.github.com/simonw/bb0a8c24eb110e6ff9878a784356659a