Fabric Wiki

To add enchantments to your mod, you'll need to:

• create a class that extends Enchantment or another existing Enchantment (such as DamageEnchantment)
• register your enchantment
• add custom functionality or mechanics if needed
• add translations for your enchantment ¹⁾

Enchantments can either have custom functionality implemented separately (such as smelting ores mined) or can use already existing mechanics (such as DamageEnchantment), which are applied when appropriate. The base Enchantment class also has several methods to create functionality, such as an “on enemy hit” method.

We'll be creating an enchantment called Frost, which slows mobs. The slowness effect durability & potency will grow relative to the level of the enchantment.

public class FrostEnchantment extends Enchantment 
{
    public WrathEnchantment(Weight weight, EnchantmentTarget target, EquipmentSlot[] slots)
    {
        super(weight, target, slots)
    }
}

You'll have to override a few basic methods for basic functionality:

getMinimumPower is the minimum level required to get the enchant in an enchanting table. We'll set it to 1, so you can get it at any level:

@Override
public int getMinimumPower(int int_1)
{
    return 1;
}

getMaximumLevel is the number of tiers the enchantment has. ²⁾

@Override
public int getMaximumLevel()
{
    return 3;
}

Finally, we'll implement our slowness effect in the onTargetDamage method, which is called when you whack an enemy with a tool that has your enchantment.

@Override
public void onTargetDamaged(LivingEntity user, Entity target, int level)
{
    if(target instanceof LivingEntity)
    {
        ((LivingEntity) target).addPotionEffect(new StatusEffectInstance(StatusEffects.SLOWNESS, 20 * 2 * level, level - 1));
    }
 
    super.onTargetDamaged(user, target, level);
}

Pretty simple logic: if the entity we're hitting can have status effects, give it slowness. The time is 2 seconds per level, and the potency is equivalent to the level.

Registering enchantments follows the same process as usual:

private static Enchantment FROST;
 
@Override
public void onInitialize()
{
    FROST = Registry.register(
        Registry.ENCHANTMENT,
	new Identifier("tutorial", "frost"),
	new FrostEnchantment(
	    Enchantment.Weight.VERY_RARE,
	    EnchantmentTarget.WEAPON,
	    new EquipmentSlot[] {
		EquipmentSlot.MAINHAND
	    }
	)
    );
}

This registers our enchantment under the namespace tutorial:frost, sets it as a very rare enchantment, and only allows it on main hand tools.

You'll need to add a translation to your enchantment as well. Head over to your mod lang file and add a new entry:

{
    "enchantment.tutorial.frost": "Frost"
}

If you go in-game, you should be able to enchant main hand weapons with your new enchant: