Item inputs and outputs

Item inputsCopy Anchor Link

Each shared-format input_items entry is an object containing ingredient, with an optional count of 1 to 2³¹−1 that defaults to 1. The item’s stack limit bounds the usable count.

An exact item:

{"ingredient": "minecraft:iron_ingot", "count": 2}

An item tag:

{"ingredient": "#c:ingots/steel", "count": 2}

The leading # denotes an ingredient tag; a plain string names an item.

An input can also demand component values. For example, this is the form of a cold depleted-uranium requirement:

{
  "ingredient": "hbm:waste_uranium",
  "components": {
    "hbm:decay_heat": false
  }
}

For fluid-container inputs and reusable component predicates, see Ingredients and Components.

Item outputsCopy Anchor Link

The shared output_items field is an array of output positions. Each position can hold a fixed output or, for machines which roll outputs, a weighted choice.

chance rolls once for the entire stack. The shortcut rounds the probability to a weight out of 1000; valid results are 1–999. Omit chance for a guaranteed output.

For multiple alternatives, put a weighted list inside one output position:

{
  "output_items": [
    [
      {"data": {"id": "minecraft:paper", "count": 3}, "weight": 3},
      {"data": {"id": "minecraft:stick"}, "weight": 1},
      {"data": {}, "weight": 4}
    ]
  ]
}

This output position yields paper with probability 3/8, a stick with probability 1/8, or nothing with probability 4/8. Additional outer-array entries define separate output positions.

Each weight is 0 to 2³¹−1; their sum may be 0 to 2³¹−1. A positive sum selects an output.

For crafting outputs selected from an item tag, see Item-tag result.

Custom machines roll weighted choices. Shredder recipes require one fixed output position and exactly one count-1 input; fluids, duration and power stay empty or zero.