Rat Upgrade: Crafting[]
The Crafting Upgrade allows a rat to automatically craft items for you.
Like all Rat Upgrades, it can be applied to a rat by placing it in the upgrade slot in the Rat Menu. Once applied, the rat then has to be standing on top of a Rat Crafting Table. This can be easily achieved by the player standing atop of the table with a rat on their shoulder, and dropping the rat by crouching and punching in the air.
Once the rat is on top of the Rat Crafting Table, right-clicking the rat will open the table's crafting interface. Note that the crafting table will not activate unless there is a rat with the upgrade equipped on top; a regular rat will not activate the table.
The upper left-most box is where will you put the item you want the rat to craft. The upper right-most box is where the crafted item will be placed once created. The Required Items row is where you will see what materials are required for crafting, though note that the amount is not specified. The Input row is where the required items are to actually be placed.
Automation[]
Automation is fairly simple.
Have one rat bring materials from one chest to the crafting table, and another rat taking the then-produced item out of the table, and store it in a different chest.
If there is more than one type of material needed to craft something, then you can have even more rats bring the necessary materials from other chests.