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, \texttt{i32::MAX}] 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, component predicates and the handling of changed components, 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, except in the Assembly Machine, Assembly Factory, Precision Assembly Machine, Chemical Plant, Chemical Factory, PUREX, Supercomputer, Rock Mill, Plasma Forge and Fusion Reactor Vessel, which roll each item of the stack separately. 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 \frac{3}{8}, a stick with probability \frac{1}{8}, or nothing with probability \frac{4}{8}. Additional outer-array entries define separate output positions.

Each weight is [0, \texttt{i32::MAX}]; their sum may be [0, \texttt{i32::MAX}]. A positive sum selects an output.

In the machines listed above, a list holding one item and one empty entry rolls like chance, and a position with several possible items outputs only into an empty slot.

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

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