Commands

All require permission level 2 (gamemaster) — the same tier as /reload.

Species

/ancientcreature species list

Every loaded species with its movement category and size.

6 species loaded:
  ancientcreature:ankylosaurus  [land]  1.9x1.45
  ancientcreature:deinonychus  [land]  0.95x1.45
  ancientcreature:megalodon  [aquatic]  2.8x1.6
  ancientcreature:pteranodon  [flying]  1.5x1.4
  ancientcreature:triceratops  [land]  1.8x2.2
  ancientcreature:tyrannosaurus_rex  [land]  1.2x2.0

If nothing is listed, the datapack half is not loaded. The message tells you where the files belong.

/ancientcreature species get <id>

Everything resolved for one species — including the behaviour list after the profile has been expanded and your overrides applied, which is the quickest way to check a profile did what you meant.

Species ancientcreature:triceratops
  category: land
  size: 1.8 x 2.2, eye 1.4
  growth: adult_age 24000, baby_scale 0.5
  incubation: 1000 ticks, biomes #minecraft:is_overworld
  hunger: max 20.0, hunts at 10.0, full at 18.0, -1 every 1200 ticks
  attribute minecraft:max_health = 45.0
  ...
  behavior ancientcreature:charge_attack (priority 1, goal)
  behavior ancientcreature:territorial (priority 2, target)
  ...

Tab-completes loaded species ids.

/ancientcreature species validate

Re-runs validation over everything loaded and reports what fails. Useful after editing a pack by hand.

/ancientcreature species reload

Reloads datapacks, picking up species changes. Equivalent to /reload, and provided so you do not have to remember which one refreshes species.

Behaviour

/ancientcreature behaviors

Every registered component type with its default priority, and every profile — including any added by other mods. The authoritative list for the version you are running.

Hunger

/ancientcreature hunger <targets>

Reports how fed the selected creatures are, and whether that is enough to make them hunt.

ancientcreature:tyrannosaurus_rex: 14.0/20.0 (hunts at 10.0, full at 18.0) - not hunting

Hunger is otherwise invisible and moves on the order of minutes, so this is the way to tell a predator that is ignoring prey because it is full from one that is failing to target at all.

/ancientcreature hunger <targets> <value>

Sets hunger directly, so you can cross the hunting threshold without waiting out the decay.

/ancientcreature hunger @e[type=ancientcreature:ancient_creature,limit=1] 0

That is the quickest way to confirm a predator does start hunting — drop it to zero and watch it pick a target. Set it back to 20 and it should lose interest once it climbs past full_threshold.

See hunger for what the numbers mean.

Actions

/ancientcreature action <targets> [<action>] [<ticks>|loop [<period>]]

Forces the synchronised action that the client's animation controller keys off, so a clip can be watched on demand instead of waiting for the AI to trigger it. With no action, it reports the current one.

/ancientcreature action @e[limit=1] roar
/ancientcreature action @e[limit=1] eat 40
/ancientcreature action @e[limit=1] roar loop
/ancientcreature action @e[limit=1] none

With ticks omitted the action is held until something clears it; none always stops a loop. Note that a non-looping clip plays once and then leaves the model in its rest pose for as long as the action stays set — that is the animation's own loop mode, not a bug.

Spawning

/ancientcreature summon <species> [<pos>] [<baby>] [<variant>]

/ancientcreature summon mypack:stegosaurus
/ancientcreature summon mypack:stegosaurus ~ ~ ~
/ancientcreature summon mypack:stegosaurus ~ ~ ~ true
/ancientcreature summon mypack:stegosaurus ~ ~ ~ false albino

Tab-completes loaded species ids, and fails with a clear message if the id has no definition rather than spawning an inert creature. Without a variant, one is rolled from the species' variants list, as it would be for a hatched creature.

The species is applied before the creature is placed, so it is positioned using its own bounding box and spawns at its own maximum health — not the generic 20.

Why not /summon

Every species shares one entity type, so /summon ancientcreature:ancient_creature gives you the default species unless you hand-write the NBT:

/summon ancientcreature:ancient_creature ~ ~ ~ {Species:"mypack:stegosaurus",Variant:"albino",Age:-24000}

That still works — Age follows vanilla, negative is a baby — but it does not tab-complete and it does not tell you when the id is wrong.

Log lines worth knowing

On a successful load you should see:

Loaded 6 Ancient Creature species definitions (server side)
Loaded 6 Ancient Creature client species definitions
Loaded 6 Bedrock geometries
Loaded 32 Bedrock animations from 6 files
Loaded 6 Ancient Creature animation controllers

Problems are logged with the file path and the reason:

Invalid Ancient Creature species definition mypack:stegosaurus (...): unknown attribute(s): minecraft:speed
Client species 'mypack:stegosaurus' references missing geometry 'mypack:stego'
Animation 'animation.stego.walk' targets bone 'leg1', which the geometry does not have
No species definition for 'mypack:stegosaurus'. Creatures of this species will stay inert ...