Magic text:String variable length
You can use the string variable length magic text with the magic text [strlen=NAME] where NAME is the name of the desired variable to obtain the length of a specific string variable. You can use this to for example determine if a string is too large to show to the user without having much lag and instead write it to a file, or use it in a text manipulation with substring option. There are tons of things you can do with magic texts other than that of course.