I'm creating this thread as a “tracking issue” for a config GUI. One of the most common questions I get is about how to reduce the disenchantment cost. The mod has had a config file to adjust that for a long time now, but it's not exactly easy to use (especially due to the nested cost function definitions). There should be a GUI for it. A problem that will come up is that the mod works server-side, so the majority of configurable values will only apply in singleplayer. Maybe there could be a thing that displays the current config as JSON though, so that you can copy it when setting up a dedicated server? As for how to make the config screen, I'll probably write it by hand using vanilla classes. I know there are quite a few libraries for this, and I've also been playing around with the idea of making my own (based on the idea that, just as you can define a Codec and PacketCodec for the same class, you could have some kind of ConfigCodec), but I think it wouldn't be expressive enough and the vanilla classes honestly don't seem to be that bad to use directly. Now I'll just have to find the motivation and time to actually do this...