Tag grammar

The ovrin struct tag: a description the model reads, then a closed vocabulary of rules — required, min, max, format and enum — that get validated.

The upstream Ovrin docs describe schema tags as a structured grammar attached to Go struct fields. This defines how extraction should read, interpret, and validate each value.

Example

type Invoice struct {
    Number string `ovrin:"invoice number,required"`
    Total  float64 `ovrin:"total amount including tax,required,min=0"`
}

Why tags matter

They connect the document semantics to the Go type in a way that can be enforced at extraction time.