Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding General Probable workaround to add abilities?

It is not possible to add custom abilities, unfortunately.

That list of APIs is mostly up-to-date. Very few APIs have been modified (gotten an extra parameter) and a couple have been added, but in general that list is still quite comprehensive.