Congratulations on publishing this. I use `git add -p` quite a lot, and this project looks interesting!
I knew that you could place a `git-xyz` executable and you can call it as `git xyz`. I didn't know you could do it with flags !?!
A small video or some screenshots would help a lot. If you can record interactivity with ascii-cinema, that will be even better.
Since the OP is familiar with the Go ecosystem, they could probably use vhs[1] easily to programmatically create an interactive demo GIF. That has worked very well for me in the past.