Hi James,
All of the functions and the list of the built-in Python libraries for NAE are listed in the ArubaOS-CX Network Analytics Engine Guide for 10.03, linked here.
From what I understand, you're looking for the condition to continuously change values whenever it is hit, correct? Due to the architecture of how an agent is created, I'm unsure if the running instance would re-evaluate the variables for the conditional check, so I'm unsure how you would be able to do that without the use of Baselining or another feature improvement.
As for debugging NAE-script development, unfortunately there is not yet an alternative to uploading the script and running. I'm hoping there is a development IDE or tool out soon that will help with script development going forward!