Open class_mappings/BlacklistedFromClasses.txt and add the item's ID on its own line. Save and restart, and that item will never roll a class.

minecraft:netherite_hoe

Open the class file in classes/ and add a sources line. The class will then appear only from the sources you list.

List several to allow more than one. Leave the line out entirely to allow all sources (the default). This is exactly how rare unique classes are kept chest-only.

"sources": ["loot_chest"]

"sources": ["loot_chest", "loot_entity"]

Open the matching file in class_mappings/ (for example minecraft_swords.json) and edit the classes list. Each entry's weight sets how likely it is (higher means more common). Add or remove lines to taste, then restart.

"classes": {
  "berserker": { "weight": 100 },
  "assassin":  { "weight": 100 },
  "paladin":   { "weight": 50 },
  "lichborn":  { "weight": 10 }
}

Open the class file in classes/. rollWeight sets its base chance everywhere (higher means more common), and enabled set to false switches the class off completely without deleting the file.

"rollWeight": 100,
"enabled": true

In the item's class_mappings/ file, add a multiplier applied to every rolled value. 1.3 gives 30% stronger rolls, 0.8 makes them weaker. This is how leather, gold, and iron get their material bonuses.

"attribute_multiplier": 1.3

In the item's class_mappings/ file, exclude_attributes lists stats that will never roll on this item, and attribute_overrides changes a stat's min, max, or weight just for this item.

"exclude_attributes": ["infusedpower:generic.lifesteal"],
"attribute_overrides": {
  "infusedpower:generic.critical_rate": { "min": 0.05, "max": 0.20, "weight": 30 }
}

You can target items two ways, and you often do not need an exact item ID:

• By tag (easiest). The mod reads item tags automatically, so if a modded item already belongs to a tag, one mapping covers every item that shares it.
• By item ID. Use this only when you want to single out one specific item.

Good to know:

• You rarely need item IDs, most modded gear already carries a tag (its own, or a shared one), and tags are tracked automatically.
• If an item is covered by both a tag mapping and an item mapping, the item mapping wins, because it is the more specific match.
• Vanilla-style gear (anything that behaves like a sword, axe, armor piece, and so on) and any accessory from the Accessories API are detected automatically, so they roll classes even without a mapping.

{
  "tag": "farmersdelight:tools/knives",
  "classes": {
    "assassin": { "weight": 100 },
    "rogue":    { "weight": 100 }
  }
}

{
  "item": "supermod:ruby_sword",
  "classes": { "warrior": { "weight": 100 } }
}

In classes/, copy an existing file (for example berserker.json), rename it, and edit it. Then add your new class id to any class_mappings/ file so items can roll it (see the guide above), then restart.

{
  "id": "frostknight",
  "displayName": "Frost Knight",
  "namePrefix": "Frost Knight",
  "color": "#55FFFF",
  "rollWeight": 80,
  "setBonus": true,
  "weaponPool": [
    { "attribute": "infusedpower:generic.freeze_on_hit", "min": 0.05, "max": 0.15, "weight": 10 },
    { "attribute": "infusedpower:generic.critical_damage", "min": 0.05, "max": 0.20, "weight": 10 }
  ],
  "armorPool": [
    { "attribute": "minecraft:generic.max_health", "min": 0.5, "max": 2.0, "weight": 10 }
  ],
  "staticArmorModifiers": [
    { "attribute": "infusedpower:generic.freeze_attacker", "value": 0.05, "setBonusEligible": true }
  ]
}

What the min and max numbers mean

The number you write is not always a percentage. How it shows in-game depends on the stat:

The easy way: do not guess at numbers. Open a class that already uses the stat you want (for example berserker.json has Lifesteal and Crit Damage), copy its min and max, then nudge them. The in-game Attribute Guide explains what every stat does, and the Every attribute ID list further below gives the exact IDs to type.

operation (you can usually ignore this)

Leave it out and the mod picks the right behavior automatically: Attack Damage, Attack Speed, and Movement Speed scale off the item's base value, while everything else adds a flat amount. Only set operation if you specifically want to change that.

Two kinds of weight (rarity)

Weight can appear in two places, doing two different jobs:

• rollWeight in a class file is that class's default rarity everywhere (higher means more common).
• weight inside a mapping overrides rollWeight for that one item or group. If you list a class with no weight (like ["warrior"]), it simply uses the class's own rollWeight.

Weapon pool vs armor pool

A class rolls from weaponPool or armorPool depending on the item:

• Weapon pool: swords, axes, maces, bows, crossbows, tridents, knives, and tools (pickaxe, shovel, hoe, fishing rod).
• Armor pool: helmets, chestplates, leggings, boots, shields, and every accessory (rings, amulets, capes, and so on).

If you want a class to work on both armor and weapons, fill in both pools.

Names: namePrefix, nameSuffix, and namingMode

A class can define a prefix, a suffix, or both. The mapping's namingMode decides which actually appear:

• "prefix" uses only the prefix, like Berserker Iron Sword
• "suffix" uses only the suffix, like Iron Sword of the Guardian
• "both" (the default) allows both

Set bonuses

A set bonus needs two things to be true: the class has "setBonus": true, and the specific guaranteed stats are marked "setBonusEligible": true. Then each matching piece you wear past the first adds 20% to those stats: 2 pieces give x1.2, 3 pieces give x1.4, and so on with no cap. The tooltip shows the count, like Paladin Set: 2.

Class file (classes/*.json)

Mapping file (class_mappings/*.json)

Attribute IDs look like infusedpower:generic.lifesteal (this mod's stats) or minecraft:generic.attack_damage (vanilla stats). The in-game Attribute Guide explains what each one does; for the exact IDs to type, see Every attribute ID below.

Every stat from this mod is written as infusedpower:generic.NAME, using one of the names below. Vanilla stats use minecraft:generic.NAME instead.

Combat and damage critical_rate critical_damage super_crit double_hit combo_damage fury lifesteal backstab_damage execution_damage low_hp_damage armor_penetration magic_resist

On-hit effects poison_on_hit wither_on_hit slowness_on_hit weakness_on_hit freeze_on_hit fire_on_hit disorient_on_hit bleed_on_hit spellsurge

Damage vs creature type undead_damage arthropod_damage aquatic_damage illager_damage airborne_damage

Defense dodge barrier block_chance poison_immunity cleanse_on_hurt

When you are hurt regen_on_hurt resist_on_hurt speed_on_hurt heal_on_hurt percent_heal_on_hurt

Reactive armor (hurts attackers) thorns freeze_attacker fire_attacker wither_attacker poison_attacker

Healing and utility life_on_hit life_on_execute bonus_xp bonus_xp_mining_ore bonus_durability pack_leader dig_speed

Ranged draw_speed accuracy arrow_velocity arrow_damage explosive_arrow lightning_arrow gravity_arrow pierce

Movement and water swim_speed water_gravity

Common vanilla stats (use the minecraft:generic. prefix) attack_damage attack_speed max_health armor armor_toughness movement_speed knockback_resistance attack_knockback luck max_absorption

Complete reference files using every field at once. You only ever use the fields you need. A couple of notes: for affix counts you normally pick either minPositiveAffixes/maxPositiveAffixes or affixCountWeights (not both), and operation on a stat is optional (defaults are sensible).

{
  "id": "example_class",
  "displayName": "Example Class",
  "namePrefix": "Example",
  "nameSuffix": "of Power",
  "color": "#55FFFF",
  "enabled": true,
  "rollWeight": 100,
  "sources": ["loot_chest", "loot_entity", "loot_equipment", "craft", "inventory"],
  "validItems": ["minecraft:diamond_sword", "minecraft:netherite_sword"],
  "setBonus": true,
  "minPositiveAffixes": 1,
  "maxPositiveAffixes": 3,
  "affixCountWeights": [0, 65, 30, 5],
  "negativeAffixChance": 0.25,
  "maxNegativeAffixes": 2,
  "weaponPool": [
    { "attribute": "minecraft:generic.attack_damage", "min": 0.04, "max": 0.12, "weight": 10, "operation": "add_multiplied_base" },
    { "attribute": "infusedpower:generic.lifesteal", "min": 0.02, "max": 0.09, "weight": 10 }
  ],
  "armorPool": [
    { "attribute": "minecraft:generic.max_health", "min": 0.5, "max": 2.0, "weight": 10 }
  ],
  "negativeWeaponPool": [
    { "attribute": "minecraft:generic.attack_speed", "min": -0.06, "max": -0.02, "weight": 10 }
  ],
  "negativeArmorPool": [
    { "attribute": "minecraft:generic.armor", "min": -0.6, "max": -0.2, "weight": 10 }
  ],
  "staticWeaponModifiers": [
    { "attribute": "infusedpower:generic.fury", "value": 0.0135, "setBonusEligible": true }
  ],
  "staticArmorModifiers": [
    { "attribute": "infusedpower:generic.fury", "min": 0.005, "max": 0.01, "operation": "add_value", "setBonusEligible": true }
  ]
}

{
  "tag": "minecraft:swords",
  "item": "minecraft:diamond_sword",
  "namingMode": "both",
  "classes": {
    "berserker": { "weight": 100 },
    "lichborn":  { "weight": 10 }
  },
  "exclude_attributes": ["infusedpower:generic.draw_speed"],
  "attribute_overrides": {
    "infusedpower:generic.critical_rate": { "min": 0.05, "max": 0.20, "weight": 30 }
  },
  "attribute_multiplier": 1.3
}

Tune everything to taste, then ship your edited config/infusedpower/ folder with your pack. Players get your classes, mappings, item support, and balance automatically, with no extra setup on their end.