Craftax

An open-ended 2D survival benchmark

Description

Craftax is a reimplementation of Crafter — an open-ended 2D survival environment inspired by Minecraft. The agent navigates a procedurally generated world, gathers resources, crafts tools, fights enemies, and unlocks a hierarchy of achievements. The full Craftax version extends Crafter with floors, dungeons, magic, ranged combat, and additional creatures; Craftax-Classic is a faithful port of the original Crafter rules.

Both versions ship in a Pixels variant (rendered RGB tiles) and a Symbolic variant (flat feature vector). Episodes terminate on player death.

import stable_worldmodel as swm

# Pixel-art observation — use 'nearest' resample to keep it crisp.
world = swm.World(
    'swm/CraftaxClassicPixels-v1',
    num_envs=4,
    image_shape=(224, 224),
    image_resample='nearest',
)

# Flat symbolic observation
world = swm.World('swm/CraftaxSymbolic-v1', num_envs=4, image_shape=(64, 64))

Available Environments

Environment	Environment ID	Observation	Actions
Craftax-Classic Pixels	`swm/CraftaxClassicPixels-v1`	RGB `(63, 63, 3)`	`Discrete(17)`
Craftax-Classic Symbolic	`swm/CraftaxClassicSymbolic-v1`	Flat `(1345,)`	`Discrete(17)`
Craftax Pixels	`swm/CraftaxPixels-v1`	RGB `(130, 110, 3)`	`Discrete(43)`
Craftax Symbolic	`swm/CraftaxSymbolic-v1`	Flat `(8268,)`	`Discrete(43)`

Craftax-Classic

craftax_classic

Faithful JAX port of the original Crafter benchmark: a single overworld map with 22 achievements (gather wood/stone/iron/diamond, craft pickaxes/swords, defeat zombies/skeletons, etc.). Player perception is a 9×7 tile window plus an inventory strip; observation is rendered at the agent's tile resolution.

world = swm.World(
    'swm/CraftaxClassicPixels-v1',
    num_envs=4,
    image_shape=(224, 224),
    image_resample='nearest',
)

Environment Specs

Property	Value
Action Space	`Discrete(17)` — movement, place, craft, sleep, do
Observation Space (Pixels)	`Box(0, 1, shape=(63, 63, 3), float32)`
Observation Space (Symbolic)	`Box(0, 1, shape=(1345,), float32)`
Episode Termination	Player death
Auto-reset	Disabled (use `gym.wrappers.TimeLimit` to cap rollout length)
Environment ID	`swm/CraftaxClassicPixels-v1`, `swm/CraftaxClassicSymbolic-v1`

Info Dictionary

Key	Description
`Achievements/<name>`	0/1 indicator per Crafter achievement (22 keys, e.g. `collect_wood`, `make_iron_pickaxe`)
`discount`	0 if terminal, else 1
`env_name`	Environment label

Craftax (Full)

craftax

The full version extends Crafter with multi-floor dungeons, ranged combat (bows, fireballs, iceballs), magic, and additional creatures. Observation includes a wider tile window and a richer inventory panel; the achievement set grows to 69+ entries.

world = swm.World(
    'swm/CraftaxPixels-v1',
    num_envs=4,
    image_shape=(224, 224),
    image_resample='nearest',
)

Environment Specs

Property	Value
Action Space	`Discrete(43)` — movement, attack, cast, place, craft, level transitions
Observation Space (Pixels)	`Box(0, 1, shape=(130, 110, 3), float32)`
Observation Space (Symbolic)	`Box(0, 1, shape=(8268,), float32)`
Episode Termination	Player death
Auto-reset	Disabled (use `gym.wrappers.TimeLimit` to cap rollout length)
Environment ID	`swm/CraftaxPixels-v1`, `swm/CraftaxSymbolic-v1`

Info Dictionary

Key	Description
`Achievements/<name>`	0/1 indicator per achievement (69+ keys, including `cast_fireball`, `cast_iceball`, dungeon traversal, ...)
`discount`	0 if terminal, else 1
`env_name`	Environment label

Tips

For the Pixels variants, pass image_resample='nearest' to swm.World so pixel-art tiles stay crisp when upscaled — the default bilinear resampling blurs them.
The wrapper does not distinguish terminated from truncated: every episode end is reported as terminated=True. Wrap with gymnasium.wrappers.TimeLimit if you need a step budget.