As you might have noticed, Visual Studio Code's git integration now has a feature where you can generate a commit message based on your staged commits.
It would be very nice to have this feature in Sourcetree as well. It could even be expanded by adding a default prompt, like "start every commit with ADD:, CHANGE: or REMOVE:".
For reference: How to generate commit messages with AI in Visual Studio Code.
I was looking for a way to extend Sourcetree myself, like so many other apps allow for these days (e.g. power-ups on Trello), but unfortunately this doesn't seem to be an option.