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

Links