I always have the docs open when I’m developing extensions. It’s kind of a long page and it’s not that straightforward to find the API you need if you don’t know it exists already, but give it a quick read and you’ll soon get familiar with it, overall I’m pretty satisfied with the available APIs.
Why I wrote 33 VSCode extensions and how I manage them
Fabio Spampinato

I use it directly in VSCode from Typescript, don’t you find it more convenient that way?