OptionalAllowedOptional closed set of allowed categories (only meaningful when
Kind === 'category'). When provided, an out-of-set model response is
coerced to null so an unexpected label never silently enters the matrix.
The feature column name produced from the model's output (also the key the model is asked to emit in its structured response).
Whether the emitted value is a categorical label or a numeric scalar.
The structured output contract for a VisionLLMFeatureStep — names the single value the model emits and the shape it takes.