{
    "criteria": {
      "item": {
        "trigger": "minecraft:item_durability_changed",
        "conditions": {
          "item": {
            "predicates": {
              "minecraft:custom_data": {
                "mt.legendary_spawn": 1
              }
            }
          }
        }
      }
    },
    "rewards": {
      "function": "mt:items/utility/tier_spawn/legendary/spawn"
    }
  }