Interface MwlHookDeclaration

What a hook says about the attributes its own [hook] calls carry. A hook's name is checked at compile time already; without this its attributes are not, so a typo in one of a command hook's 18 modes is only discovered at the moment the scenario runs it.

The declaration is the hook's, not the tag's: MWG checks [hook] invocations, where every attribute but name belongs to the hook. A hook= attribute on a condition-bearing tag ([victory] hook=predicate:holds value=3) keeps that tag's own schema and this does not apply, since value there is the condition's to define.