If you simply want to change case of tags and filenames, please see the action "Case Conversion" as described here:
If you really want to use a scripting function like $caps2, you'd need to use either an action "Format value" or use it while renaming the file from the tag with the converter "Tag - Filename".
However, you'd need to use $caps2(%title%,'.') so that the dot is treated as separator character.