Fill

Where an output field’s value comes from — orthogonal to how it renders. Only user and session fields show a widget.

Every variant shares the keys below. Which further keys are legal depends on kind.

Key	Type	Required	Notes
kind	"user" | "copy" | "session" | "timestamp"	yes	Selects which shape the rest of this object takes. Every other key is validated against the variant named here.

"kind": "user"

The labeler answers this field on every record.

No keys beyond the shared ones.

"kind": "copy"

Carried over from an input column. Renders no widget.

Key	Type	Required	Notes
from	string	no	Input field to copy from. Defaults to this field’s own name; naming one explicitly is how a copied column gets renamed on the way out. Its type must match this field’s type. min length 1, matches ^[A-Za-z0-9_-][A-Za-z0-9_ -]*[A-Za-z0-9_-]$|^[A-Za-z0-9_-]$

"kind": "session"

The labeler answers this once, on the setup step, and the answer is written to every exported row.

No keys beyond the shared ones.

"kind": "timestamp"

Stamped by the app when the record becomes complete, and again on every later edit. Renders no widget.

No keys beyond the shared ones.