What a validating middleware checks, branded onto the middleware function so a documentation generator can describe the route without importing the plugin that produced it.

This is a description, not a mechanism: the middleware still performs the validation, and removing the metadata changes no runtime behaviour.

The schema is carried verbatim — the same object the caller passed — so a reader transforms it with whatever schema support it already has. It is typed unknown rather than a Zod type because @setu-ts/common depends on nothing and the validation contract accepts any object exposing safeParse.