Hazel doesn't rename based on "Text content" element

I created a .txt file with the content "This is a test". Then tried to get Hazel to Rename the file based on the pattern element Text Content (Pattern > Other > Text content). However, this doesn't work. Should it?
Also, in case that this function is actually supposed to work, it would be good to be able to truncate the content to a variable amount of characters, e.g. keep only the first 20 letters.
Image: https://imgur.com/a/JA168
Unfortunately couldn't paste it to the forum because it got too large for some reason.
Also, in case that this function is actually supposed to work, it would be good to be able to truncate the content to a variable amount of characters, e.g. keep only the first 20 letters.
Image: https://imgur.com/a/JA168
Unfortunately couldn't paste it to the forum because it got too large for some reason.