Mp3tag has no dedicated method or option to put remarks or descriptions into actionsgroup scripts.
But within an action "Format value" you may misuse the "square bracket clamb" to store descriptive text.
Example ... see there ...
CD´s einer Compilation zusammenfügen
Example see there ...
Tracknummer 3-stellig mit führenden Nullen
https://forums.mp3tag.de/index.php?act=atta...ost&id=5682
DD.20160309.1713.CET