AttributeModify / NeoAttributeModify

Customize item attributes, mining behavior, durability, and item progression with JSON datapacks. No Java required.

AttributeModify is the Forge edition for Minecraft 1.20.1. NeoAttributeModify is the NeoForge edition for Minecraft 1.21.1.

Both projects use the same datapack folder layout and the same general JSON style. The main difference is how item data is read internally:

1.20.1 evaluates NBT-style data
1.21.1 evaluates data components
For cross-version packs, component-like paths such as component:apotheosis:rarity can be used to keep configs easier to maintain

What You Can Do

Add, modify, or remove attributes on vanilla and modded items
Target standard equipment slots, body, and optional Curios slots
Use shorthand syntax with automatic slot detection
Apply rules to single items or whole item tags
Make rules conditional with NBT or component matching
Override mining speed and mining tier
Override durability and optional durability triggers
Roll randomized quality tiers on item creation
Mark items as decorative
Split configs across multiple files and hot-reload them with /reload
Sync everything automatically in multiplayer

Datapack Location

Place your files in:

data/<namespace>/item_attributes/<file>.json

Entries from multiple files are merged, so you can organize your datapack however you want.

Examples

1. Single shorthand attribute with automatic slot detection

{
  "minecraft:diamond_chestplate": {
    "attribute": "minecraft:generic.luck",
    "action": "add",
    "amount": 1.0,
    "operation": "add_value"
  }
}

Useful for quick changes. Armor and common tools can infer the correct slot automatically.

2. Multiple shorthand attributes on the same item

{
  "minecraft:diamond_boots": {
    "attributes": [
      {
        "attribute": "minecraft:generic.armor",
        "action": "add",
        "amount": 1.0,
        "operation": "add_value"
      },
      {
        "attribute": "minecraft:generic.movement_speed",
        "action": "add",
        "amount": 0.03,
        "operation": "add_multiplied_total"
      }
    ]
  }
}

3. Explicit equipment slots with `add`, `modify`, and `remove`

{
  "minecraft:diamond_sword": {
    "equipment_slots": {
      "mainhand": [
        {
          "attribute": "minecraft:generic.attack_damage",
          "action": "modify",
          "amount": 10.0,
          "operation": "add_value"
        },
        {
          "attribute": "minecraft:generic.attack_speed",
          "action": "remove"
        }
      ]
    }
  }
}

4. Curios slot example

Requires Curios to be installed.

{
  "mymod:magic_ring": {
    "curios_slots": {
      "ring": [
        {
          "attribute": "minecraft:generic.max_health",
          "action": "add",
          "amount": 4.0,
          "operation": "add_value"
        }
      ]
    }
  }
}

5. Apply one rule to a whole item tag

{
  "#minecraft:swords": {
    "equipment_slots": {
      "mainhand": [
        {
          "attribute": "minecraft:generic.attack_knockback",
          "action": "add",
          "amount": 0.5,
          "operation": "add_value"
        }
      ]
    }
  }
}

6. Conditional attributes with NBT or component matching

{
  "minecraft:diamond_sword": {
    "equipment_slots": {
      "mainhand": [
        {
          "attribute": "minecraft:generic.attack_damage",
          "action": "add",
          "amount": 5.0,
          "operation": "add_value",
          "nbt": {
            "path": "component:apotheosis:rarity",
            "operator": "equals",
            "value": "apotheosis:mythic"
          }
        }
      ]
    }
  }
}

You can use path or key inside the nbt block.

7. Quality system

{
  "minecraft:iron_sword": {
    "quality_system": {
      "tag_path": "quality",
      "triggers": ["craft", "loot", "villager_trade", "apotheosis_sync"],
      "levels": [
        { "value": "common", "weight": 60 },
        { "value": "rare", "weight": 30 },
        { "value": "mythic", "weight": 10 }
      ]
    }
  }
}

8. Mining speed and tier overrides

{
  "minecraft:iron_pickaxe": {
    "mining": [
      {
        "speed": 12.0,
        "tier": "diamond",
        "nbt": {
          "path": "quality",
          "operator": "equals",
          "value": "mythic"
        }
      },
      {
        "speed": 8.0,
        "tier": "iron"
      }
    ]
  }
}

9. Durability override and custom durability triggers

{
  "minecraft:diamond_pickaxe": {
    "durability": 3000,
    "durability_triggers": ["block_break", "right_click"]
  }
}

Supported custom durability triggers:

melee_hit
block_break
right_click

10. Decorative items

{
  "minecraft:carved_pumpkin": {
    "decorative": true
  }
}

Quick Reference

Top-level blocks

attribute: single shorthand attribute entry
attributes: shorthand array of attribute entries
equipment_slots: explicit vanilla equipment slots
curios_slots: explicit Curios slots
quality_system: weighted quality roll rules
mining: mining speed and tier overrides
durability: max durability override
durability_triggers: optional triggers for custom durability
decorative: marks an item as decorative

Standard equipment slots

mainhand, offhand, head, chest, legs, feet, body

Actions

add: add modifiers on top of existing stats
modify: replace the base modifiers for that attribute
remove: remove that attribute from the item for the target slot

Operations

add_value
add_multiplied_base
add_multiplied_total

Accepted aliases:

addition
multiply_base
multiply_total

NBT or component operators

equals
not_equals
greater
greater_or_equal
less
less_or_equal
exists
not_exists
contains
starts_with
ends_with
matches_regex

Quality triggers

craft
loot
villager_trade
apotheosis_sync

Multiplayer and Reloading

/reload re-reads datapack files without restarting the game
Servers sync attribute, mining, durability, and decorative data to clients
The logic is designed for multiplayer use

Compatibility Notes

Works with vanilla items and modded items
Curios support is optional
Apotheosis-style data checks are supported through conditional matching
Use modifier_id if you want a fixed custom modifier identity for compatibility with other mods

Attribute Modify