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Spawn Rules Documentation - minecraft:spawn_biomeconditions

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Defines the conditions under which an entity can spawn, including biome filters, brightness, height, and herd settings.

Spawn Biome Conditions Properties

Name Default Value Type Description
minecraft:biome_filter (Biome Filter) {"AND":null,"NOT":null,"OR":null,"all":null,"all_of":null,"any":null,"any_of":null,"none_of":null} Biome Filter item Filters allow data objects to specify test criteria which allows their use.
minecraft:biome_filter (as Array of objects) not set Array of objects Array of filter objects.
minecraft:brightness_filter not set Brightness Filter item
minecraft:delay_filter not set Delay Filter item
minecraft:density_limit not set Density Limit item
minecraft:difficulty_filter not set Difficulty Filter item
minecraft:disallow_spawns_in_bubble not set Object Prevents spawning inside bubble columns.
minecraft:distance_filter not set Distance Filter item
minecraft:height_filter not set Height Filter item
minecraft:herd [] Object Specifies herd spawning configuration. Can be a single herd object or an array of herd objects.
minecraft:herd (as Array of objects) not set Array of objects Array of herd configurations.
minecraft:is_experimental not set Object
minecraft:is_persistent not set Object
minecraft:mob_event_filter not set Mob Event Filter item
minecraft:permute_type [] Object Specifies permutation types for spawning. Can be a single object or an array of permutation objects.
minecraft:permute_type (as Array of objects) not set Array of objects Array of permutation configurations.
minecraft:player_in_village_filter not set Player In Village Filter item
minecraft:spawn_event {"event":""} Spawn Event item
minecraft:spawns_above_block_filter {"blocks":[],"distance":1} Spawns Above Block Filter item
minecraft:spawns_lava not set Object Indicates the entity can spawn in lava.
minecraft:spawns_on_block_filter [] Array of objects Specifies blocks on which this entity can spawn. Can be a single block name string, an array of block objects with name property, or an array of strings representing block names.
minecraft:spawns_on_block_filter (as String) not set String A single block name string
minecraft:spawns_on_block_filter (as Array of strings) not set Array of strings An array of block name strings
minecraft:spawns_on_block_prevented_filter [] Array of strings Specifies blocks on which this entity cannot spawn. Can be an array of block name strings.
minecraft:spawns_on_surface not set Object
minecraft:spawns_underground not set Object
minecraft:spawns_underwater not set Object
minecraft:weight not set Weight item
minecraft:world_age_filter not set World Age Filter item

minecraft:biome_filter

Filters allow data objects to specify test criteria which allows their use. Filters can be defined by a single object of type (Filter Test), an array of tests, collection groups, or a combination of these objects. This uses the Minecraft filter dataType (20) which properly handles the complex filter structure including string operators and values.

Biome Filter

Biome Filter Properties

JSON path: minecraft:biome_filter

Name Default Value Type Description
all_of not set Array of objects All of these tests must pass.
any_of not set Array of objects Any of these tests must pass.
domain not set String The domain the test should be performed in.
none_of not set Array of objects None of these tests must pass.
operator not set String The comparison to apply with 'value'.
subject not set String The subject of this filter test.
test not set String The name of the test to apply.
value not set Integer number The value being compared with the test.

Spawn BrightnessFilter

Restricts mob spawning based on light level at the spawn location. Hostile mobs typically spawn in darkness (light level 0-7), while passive mobs spawn in brighter areas. Allows setting min/max brightness thresholds and whether to adjust for spawning on a block surface.

Spawn BrightnessFilter Properties

JSON path: minecraft:brightness_filter

Name Default Value Type Description
adjust_for_weather false Boolean true/false
max 15 Integer number
min 0 Integer number

Spawn DelayFilter

Delays entity spawning by a configurable amount of time after spawn conditions are met. Useful for preventing immediate respawning after mob deaths or creating spawn cooldowns for rare creatures.

Spawn DelayFilter Properties

JSON path: minecraft:delay_filter

Name Default Value Type Description
identifier String
max 0 Integer number
min 0 Integer number
spawn_chance 100 Integer number

Spawn DensityLimit

Limits how many of this entity type can exist in an area, with separate caps for surface and underground spawning. This prevents overpopulation and controls mob density for performance and gameplay balance.

Spawn DensityLimit Properties

JSON path: minecraft:density_limit

Name Default Value Type Description
surface -1 Integer number
underground -1 Integer number

Spawn DifficultyFilter

Restricts mob spawning to specific difficulty levels (Peaceful, Easy, Normal, Hard). For example, hostile mobs don't spawn on Peaceful, and some dangerous variants only appear on Hard difficulty.

Spawn DifficultyFilter Properties

JSON path: minecraft:difficulty_filter

Name Default Value Type Description
max hard Max choices
min peaceful Min choices

Max choices

Value Title Description
easy Easy
hard Hard
normal Normal
peaceful Peaceful

Spawn DistanceFilter

Controls spawning based on distance from the nearest player. Mobs typically spawn within a certain radius around players (24-128 blocks) and despawn when players move too far away.

Spawn DistanceFilter Properties

JSON path: minecraft:distance_filter

Name Default Value Type Description
max 128 Integer number
min 24 Integer number

Spawn HeightFilter

Same structure as Spawn DistanceFilter.

Spawn MobEventFilter

Controls spawning based on whether a specific mob event is active. Mob events are world-level toggles (like raids or wandering traders) that can enable or disable certain spawn behaviors.

Spawn MobEventFilter Properties

JSON path: minecraft:mob_event_filter

Name Default Value Type Description
event String

Spawn PlayerInVillageFilter

Restricts spawning based on whether a player is within village boundaries. Used for village-specific spawns like iron golems, cats, and raid mobs that should only appear when players are near villages.

Spawn PlayerInVillageFilter Properties

JSON path: minecraft:player_in_village_filter

Name Default Value Type Description
distance not set Integer number
village_border_tolerance 10 Integer number

Spawns Above Block Filter

Filters spawning based on blocks above the spawn location. This component appears to have been deprecated or changed in versions after 1.17.20.

Note

This spawn condition was used in versions 1.17.20 and earlier but appears to have been removed or replaced in newer versions.

Note

This item no longer works after format versions of at least 1.18.0.

Spawns Above Block Filter Properties

JSON path: minecraft:spawns_above_block_filter

Name Default Value Type Description
blocks [] Object
distance 1 Integer number

Spawn Weight

Defines the relative probability of this entity spawning compared to other entities in the same biome and spawn pool. Higher weight values mean more frequent spawns. A weight of 100 is typical for common mobs.

Spawn Weight Properties

JSON path: minecraft:weight

Name Default Value Type Description
default not set Integer number
rarity 0 Integer number

Spawn WorldAgeFilter

Same structure as Spawn DistanceFilter.

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