Bi-entity Condition Types

A bi-entity condition checks a relationship or a comparison between two entities: an actor and a target. The pair is supplied by whatever data table declares the condition, so the condition itself only describes what to check about the two entities it is given.

Bi-entity conditions are a Java (built-in) registry, so their type ids are fixed and a data pack cannot add new ones. type selects the built-in type and its value is one of the ids tabulated on this page, written with the mxt namespace. A data pack never adds or removes entries in this registry. Only Java code or the KubeJS bridge can introduce custom condition types — see the KubeJS API.

In the table below, a field name followed by ? is optional; every other listed field must be present. The Fields column lists the JSON keys taken directly from the type's codec.

Common Structure

A condition is a JSON object whose type field names the built-in type. All remaining keys are the fields declared by that type.

{
  "type": "mxt:distance",
  "maximum": 8
}

Because conditions are used as values inside other data tables, the same structure usually appears nested under a field such as bientity_condition:

"bientity_condition": {
  "type": "mxt:actor_condition",
  "condition": {
    "type": "mxt:entity_type",
    "entity_type": "minecraft:player"
  }
}

Anywhere a bi-entity condition is expected, an array of conditions is also accepted. The array is shorthand for mxt:and and passes only when every entry passes:

"bientity_condition": [
  { "type": "mxt:can_see" },
  { "type": "mxt:distance", "maximum": 16 }
]

Directed and Undirected Use

Most bi-entity conditions distinguish the actor from the target, so swapping the two entities changes the result. mxt:undirected runs a nested condition in both directions, and mxt:both / mxt:either deliberately apply the same entity condition to both endpoints. Nested entity checks use the entity condition types family.

Datapack Visual Editor

The Datapack Visual Editor shows the field list of every type interactively, which is handy for checking a field name without reading the table here.

Condition Types

Type	Fields	Description
mxt:always_true	—	Always passes.
mxt:js	id, params?	Calls a bi-entity condition handler that was registered through the KubeJS bridge.
mxt:and	conditions	Passes only when every nested bi-entity condition passes.
mxt:or	conditions	Passes when at least one nested bi-entity condition passes.
mxt:not	condition	Negates a nested bi-entity condition.
mxt:chance	chance	Passes randomly with the given probability between 0 and 1.
mxt:constant	value	Always returns the given boolean value.
mxt:distance	maximum	Checks that the distance between the actor and the target is at most maximum.
mxt:team	same_team?	Compares the actor's alliance with the target; with the default same_team of true it requires an alliance, and with false it requires the opposite.
mxt:relation	allied?	Compares the actor's ally relationship with the target; with the default allied of true it requires an ally, and with false it requires a non-ally.
mxt:friend	—	Passes when the actor considers the target a friend.
mxt:element_overcomes	—	Passes when at least one of the actor's spirit root elements overcomes an element of the target's spirit roots. It asks whether the relation exists, not what it is worth — the multiplier of an edge belongs to the damage pipeline, so content that only needs the pairing writes 1.0.
mxt:can_see	shape_type?, fluid_handling?	Checks that the target is within 128 blocks of the actor in the same level and that no block clips the line between their eye positions.
mxt:actor_condition	condition	Tests an entity condition against the actor.
mxt:target_condition	condition	Tests an entity condition against the target.
mxt:both	condition	Passes when the entity condition passes for the actor and for the target.
mxt:either	condition	Passes when the entity condition passes for the actor or for the target.
mxt:riding_recursive	—	Passes when the target appears anywhere in the actor's riding chain, not only as the direct vehicle.
mxt:same_team	—	Passes when the actor is on a scoreboard team and is allied to the target.
mxt:relative_rotation	axis?, actor_rotation?, target_rotation?, comparison, compare_to	Compares the actor's and the target's rotation vectors.
mxt:undirected	condition	Passes when the nested bi-entity condition passes in either direction.

mxt:can_see Values

shape_type uses the vanilla clip shape and defaults to visual, so transparent blocks such as glass do not block the check. fluid_handling defaults to none; the other vanilla fluid modes are source_only, any and water. mxt:relative_rotation restricts the axes with axis, which is an array of x, y and z and defaults to all three, and chooses which rotation each endpoint contributes through actor_rotation (head by default) and target_rotation (body by default).

Similar Types

mxt:team, mxt:same_team and mxt:relation answer almost the same question with slightly different rules: mxt:same_team additionally requires the actor to actually be on a team, mxt:team and mxt:relation only compare the alliance result and can be inverted through their field.