This isn't quite what you're asking, but I just want to make sure that you (and/or newcomers who find this thread) are aware of the existing way of getting something more descriptive (or concise, etc.) into tabs and lists (etc.) — namely, the caption field:
By default, if the caption field for a tiddler has a value, your tab set will use that field to label the tabs; if there is no such field, it will show the title.
Are you using the caption field for some other purpose, so that you cannot use it for what you're calling "description"?
If you already have put work into populating a "description" field, there's also a utility here somewhere in this group for renaming fields. Follow up if that would be useful.
-Springer