It's possible the Description and Comments configured for MARC validation display somewhere else already, but it would be nice if there were a couple of buttons to display that data in the MARC tooltips. The Description would be helpful for any tags that aren't used regularly or for staff with limited familiarity with MARC formats while the Comments could be useful in communicating local cataloging policies. Bonus points if we could allow staff with the appropriate permissions to edit the Description and Comments directly in the tooltip. It's not a particularly good example, but you could include something like "Please remove all $2fast headings." in a comment on the 655 validation if that was part of local cataloging policies.

Additionally, I feel like the Tag Name should display somewhere in the tooltip. Probably near the top or to the left of the tooltip. Seems a little odd that isn't there already.