Get latest commit description by script the easiest way

Hi, i’m new at GitHub, and now making my first “programming” project. I read about the api and it’s a huge bunch for me of things to do to set up a GitHub app…
So what I’m asking about now is, if i even need one.
The only thing I want is to get the description of the newest commit of my repository in my node.js script (as string).
I think the easiest way to do this is to use a webhook, but i’m not sure, and i don’t know how i set this up.
I can read me into it, but i don’t want to if it would be the wrong way, so i hope someone with more experience could tell me what’s the easiest way of setting up that very simple task.