This mod is for the Fabric mod loader and 
Also works on Quilt!
Supports Cloth Config and Mod Menu for configuration, but neither is required.
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Villager See, Villager Do works server-side and in singleplayer.
Villager See, Villager Do
This mod provides a way to control villagers' trades.
When a villager has a workstation but has not leveled up, they'll puck up items they could potentially trade based on their profession. When they do, their trades will reset. From then on when they gain trades, they'll replace as many as possible of their random trades with trades for items they've been given.
Villagers won't trade anything that they couldn't have traded without the mod installed.
It's easier to explain by example, so...
A toolsmith villager will pickup both a diamond pickaxe with silk touch (a possible vanilla trade) and a diamond pickaxe with mending (not a possible vanilla trade).
When the toolsmith is leveled up to master (the level at which they can trade diamond pickaxes), it will choose one of those pickaxes.
If it chooses the silk touch pickaxe, it will trade that pickaxe.
If it chooses the mending pickaxe, it will reject that trade (it'll shake its head and make angry particles), then it'll try again to find an item it's picked up to trade, this time selecting the silk touch pick, which it will accept and trade.
Some things to note:
- any prior work penalty (increased cost from use in an anvil) will be reset when an item is selected for a trade, so there's no disadvantage to combining two lower-tier enchanted items.
- renamed enchanted items will retain their names when traded
- damaged enchanted items will remain damaged when traded
Lastly, there's one quality-of-life feature: after a villager has picked up some items, throw them an emerald and they'll return all the items (this only works if they haven't been traded with).
This feature can be configured either through Mod Menu or by editing .minecraft/config/villager_see_villager_do.json
Translating
If you'd like to translate Villager See, Villager Do (there are only a few lines of text), follow this link.
New translations will be added once approved without the mod needing an update thanks to CrowdinTranslate.
This mod is only for Fabric (works on Quilt, too!) and I won't be porting it to Forge. The license is MIT, however, so anyone else is free to port it.
I'd appreciate links back to this page if you port or otherwise modify this project, but links aren't required.