Metadata for the data model / json schema

[ym-han]

The issues to think about / experiment with:

1. How exactly to bundle metadata for each of the fields in the data model that we need from user, in L4? What kind of syntax would be ergonomic and extensible for this?
2. How important is it to have few shot examples for the data model in the prompt?
   We probably want to give users a way to inject few shot examples that should apply regardless of the specific field.
   But how important would it be to, e.g., allow users to also associate few shot examples with specific fields (though admittedly this shouldn't be hard to implement --- could put it into an 'examples' property for the field in the schema --- so maybe it doesn't matter). .
3. It'd be interesting, though, to see whether even a 7b base model would be good enough at the constrained decoding when there are richer descriptions but no few shot examples. It would at least improve my intuition for these models perform with constrained decoding.