There is the template for element scripting in lua:

Assign elem

elem properties

create function

update function

graphic function.

This creates a script that will work at the element/ particles level.

Now, what template is there if I wanted to code a Tool that is not element-bound?

Like another tool to fit in the Tools menu?

I know there are functions that are screen space based (.partPosition, .partID, etc) I know how to call them from the console, but how can I call them from a menu icon, link them to a user selection, without having to create particles, and without working at the global scope.

Hoping this is sufficiently clear