Auto Lectern

Auto Lectern cycles the trades of a librarian villager by breaking and placing its lectern, so the player does not have to do it by hand. A trade mode setting chooses between the cheapest offer, an enchanted book, or no automatic trading. In the cheapest mode the mod trades paper first when enough paper is in the inventory; when there is not enough paper, it falls back to an enchantment instead. An attempt that cannot complete is skipped rather than forced, so the mod will not trade when no suitable offer is available.

Goals are the other half of the mod. A goal names an enchantment, a level and a maximum or minimum emerald price, for example mending at a low price or Unbreaking level 10 within a price range of 10 to 32 emeralds. Added goals are listed with a command, and the cycle keeps running until a goal is met. The break cooldown can be set to the default Minecraft value or turned off, and a log option displays each trade in chat. The mod is client-side only, so servers do not need it, and it is distributed under the Creative Commons Attribution Non Commercial Share Alike 4.0 license, which means the mod is not open source.