It does look like that came close to a solution here with @Aciid's suggestion of adding a restricted: true parameter that would indicate that unless something is specifically enumerated or not known by the current tools version, it is not supported.
However, it didn't land in the final version of the proposal, and it's not addressed in SE-236 or in that thread why it wasn't. Is there any clarifying information you can share as to why, or was it just too late in the discussion?