I’ve found a potentially serious problem with the call to the CLI and have temporarily withdrawn this script until I’ve managed to investigate and revise.
OK, so it doesn’t work for me! 
So I’ll ask a question as to how it is working for you-can you now browse tags in a database with Punakea? If so, can you Quick Look those documents with Punakea, or do you get a DEVONthink icon such as what you get with a Spotlight search of e DT database?
Tried it with Punakea. Mainly use Leap, Spotlight == all OK over here (I use Leap since Punakea crashes a lot 
and Leap is good at looking into packages). Spotlight requires setting up a custom search. Houdah Spot works, but it’s very cranky.
Like I said. It’s experimental; not extensively tested; just a toy; a starting point for someone more adept than me.
With a little more experimenting, I should say that the script is working fine. If I tag a file, reveal it in the Finder, and drag it to Punakea’s drop zone the file does not show any existing tags. If I run the script on the file, then drag it to the drop zone, then the tags applied in DEVONthink are associated with the document.
What I am not getting is the documents to show in a custom Spotlight search or in the Punakea browser. I’ll need to explore further to see what is (not) happening.