Hello,

I want to create a mod, that will add better bookshelves to minecraft. Those will be empty when crafted and player will be able to store books in them. Putting enchanted books into bookshelves around an enchanting table will increase the chance of getting corresponding enchantment upon using it. However, it is going to be a little bit tricky. I wonder if there is a way to change vanilla enchanting method to be able to tweak enchantemnt probabilities. If not, I can stop vanilla enchanting table GUI from appearing and instead open my own when player clicks at an enchanting table. This GUI would look similar to vanilla GUI, but would use my own enchanting method. Do you think it is a good idea?

An event is fired when a GUI is opened: GuiOpenEvent. You can use the GuiOpenEvent#setGui method to open your own GUI instead. However, I don't know if that has any side effects.