Attributes For Iron's Spells

Attributes For Iron's Spells (ais) is a NeoForge 1.21.1 mod that creates Minecraft attributes for every spell and school registered with Iron's Spells and Spellbooks, including entries supplied by addon mods.

Requirements

• Minecraft 1.21.1
• NeoForge 21.1.226 or newer
• Iron's Spells and Spellbooks 1.21.1-3.15.6 or newer
• Iron's Spells' normal dependencies: Iron's Lib, GeckoLib, Player Animator, and Curios

Attributes

Global attributes:

For every registered spell <namespace>:<path>:

• ais:spell/<namespace>/<path>
• ais:spell_cooldown/<namespace>/<path>
• ais:spell_cast_time/<namespace>/<path>
• ais:spell_cost/<namespace>/<path>

For every registered school <namespace>:<path>:

• ais:school/<namespace>/<path>
• ais:school_cooldown/<namespace>/<path>
• ais:school_cast_time/<namespace>/<path>
• ais:school_cost/<namespace>/<path>

Examples:

attribute @s ais:school/irons_spellbooks/fire base set 3
attribute @s ais:spell/irons_spellbooks/cloud_of_regeneration base set 5
attribute @s ais:spell_cooldown/irons_spellbooks/fireball base set 0.5

All attributes support vanilla operations such as add_value, add_multiplied_base, and add_multiplied_total.

Resolution rules

The effective spell level is:

max(spellbook level, ais:all, school level, spell level)

Fractional levels are floored and the result is clamped to the spell's declared level range.

Cooldown, cast time, and mana cost use:

global factor × school factor × spell factor

For example, a global factor of 0.5 and a spell factor of 0.5 produce a final factor of 0.25. These factors affect spellbook and innate casting. Negative values clamp to zero; non-finite values safely fall back to neutral behavior.

Reset command

Operators with permission level 2 can reset stored base values without removing modifiers supplied by equipment, effects, or other mods:

/ais reset <targets> all
/ais reset <targets> spell [spell_id]
/ais reset <targets> school [school_id]
/ais reset <targets> cooldown [spell_or_school_id]
/ais reset <targets> cast_time [spell_or_school_id]
/ais reset <targets> cost [spell_or_school_id]
/ais reset <targets> keep_scroll

Spell and school IDs support Brigadier autocomplete. Omitting the ID resets the whole selected category.

Spell-specific damage tags

Damage predicates can identify the exact spell that produced an Iron's Spells SpellDamageSource. Every spell automatically exposes a virtual damage-type tag using:

<spell_namespace>:spell/<spell_path>

For example, a minecraft:player_hurt_entity advancement can match only Sacrifice:

{
  "damage": {
    "type": {
      "tags": [
        {
          "id": "irons_spellbooks:spell/sacrifice",
          "expected": true
        }
      ]
    }
  }
}

No damage-type tag JSON file is required. Addon spell IDs follow the same rule, so a spell registered as hazennstuff:shadow/arcane_cards is available as hazennstuff:spell/shadow/arcane_cards. This works for addons that use or subclass Iron's SpellDamageSource, including the standard AbstractSpell#getDamageSource flow. An addon that creates an unrelated damage source does not carry a spell ID and is therefore left untagged.

A minimal development-only Sacrifice test pack is provided at ai/ais-sacrifice-damage-test. Install it in a test world, tag a target with ais_sacrifice_test_target, and that target will say hello when Sacrifice damages it. The ai directory is not part of the built mod jar.

Stability behavior

• Dynamic holders are cached during startup; casting does not scan registries.
• Missing attributes, unknown spells, missing schools, malformed scroll data, and incompatible addon entries safely no-op.
• A spell introduced too late for Minecraft's frozen attribute registry is left unchanged rather than risking a server crash.
• Attribute synchronization refreshes innate client selections only when a relevant level attribute changes.