This would mean it doesn't work with your custom command

Originally posted by @L1ving in #2063 (comment)

It doesn't work for me as well. I tried it with "emerald_ore" and it won't work. Is there any way to solve this?

BaritoneAPI.getProvider().getPrimaryBaritone().getMineProcess().mineByName(1, "emerald_ore");

What do you mean by "it didn't work" what actually happened?

And what did you do?
I'll just assume you did the same, which is registering a normal Minecraft command. As far as I know those are handled server side, so accessing Baritone from them can't work because Baritone is client only.