I have been working on enforcing assumptions recently added to the ASDF docs. Specifically, that OPERATION instances only be created by MAKE-OPERATION and SYSTEMs only be parsed inside LOAD-ASD.
I should have a merge request up for review soon, but find that it's more tricky than I expected, because we don't even play by the rules ourselves! Specifically, there are calls to MAKE-INSTANCE on OPERATIONs in the ASDF codebase itself.
Cheers, r