Rules

Rules

The world

• worldSize = 64. A 64 x 64 grid indexed (x, y), x the column 0..63 west -> east and y the row 0..63 north -> south. (0, 0) is the north-west corner.
• The outermost ring is bedrock — impassable, unmineable, unplaceable — so the cog can never leave the world. The playable interior is 62 x 62 = 3844 cells; results.cellsTotal is the whole grid, 4096.
• The cog spawns at (32, 32) facing down, on a 3 x 3 block of grass the generator forces.
• A cell holds exactly one terrain and at most one creature. The terrain table is in the README.

Generation (seeded, integer only, no floats)

Four integer value-noise fields — mountain, water, tree, cave — each built on a lattice of stride 8 whose corner values are mix64(seed, fieldSalt, gx, gy) mod 1024, bilinearly interpolated in 16-bit fixed point. For each interior cell, first match wins:

1. M > mountainThreshold: cave floor / lava / diamond / iron / coal / stone
2. W > 640 -> water, 3. W > 590 -> sand, 4. T > 700 -> tree,
3. else grass.

A playability post-pass then runs, deterministically and in this order: the 3 x 3 block at spawn is forced to grass; a tree, water and stone are forced within Chebyshev 12 / 12 / 20 if none exists; a connectivity carve joins spawn to the nearest tree, water and stone it cannot walk to; and the global minima (>= 5 coal, >= 3 iron, >= 1 diamond) are filled from the deepest stone.

Every seed is completable, the world is a pure function of (seed, variant) — nothing the policy does can shift a draw — and the seat is never told any of it. See docs/PORTING-CRAFTER.md for the connectivity carve's provenance.

Day, night and the creatures

A tick is day when tick mod dayLength < dayFraction and night otherwise; day = tick div dayLength + 1.

One spawn attempt per kind per tick, never a retry loop, and never within Chebyshev 6 of the cog — so nothing ever pops into the 9 x 9 view.

Zombies burn at dawn. On the first tick of each day every zombie whose cell is not cave floor is removed. That is what makes night, and only night, dangerous.

Fighting. do facing a creature deals 1 damage bare-handed, 2 with a wood sword, 3 with stone, 5 with iron.

Vitals

Each of health, food, drink, energy is an integer 0..9, all starting at 9. Every tick, in this order:

1. food -= 1 when tick mod 40 == 0
2. drink -= 1 when tick mod 30 == 0
3. energy -= 1 when AWAKE and tick mod 50 == 0
4. regenerate: if all three are positive and tick mod 25 == 0, health += 1
5. starve: for each of food, drink, energy that is exactly 0, if tick mod 10 == 0, health -= 1. Three zeroed vitals cost 3 health on the same tick.

9 drink lasts 270 ticks, 9 food 360, 9 energy 450. In a 1344-tick episode the cog must drink about five times, eat about four times and sleep about three times — which is exactly why wake_up, eat_cow, eat_plant and collect_drink are achievements and not distractions.

The turn, and the tick

Per command turn: the observation is built, one LLM request is issued (attempt-1 deadline 6 s), retried once (3 s), and on a second failure the forager scripted plan is computed server-side and a fallback record is written. The reply's actions are validated (invalid entries are dropped, never rewritten), the macros are expanded against the known map as of turn start, and the queue is truncated to 24 primitives. Nothing carries over.

Then, for each of the next turnTicks ticks:

1. tick += 1
2. pop the next primitive; an empty queue is a real noop
3. apply the primitive
4. vitals, the five steps above
5. world tick: saplings ripen, the phase is recomputed, zombies burn at dawn
6. spawns: one bounded attempt each for cow, zombie, skeleton
7. creatures act, in the stable order: arrows, skeletons, zombies, cows
8. achievements: a newly true predicate is recorded and stamped
9. death check
10. visibility: the 9 x 9 window is merged into the known map
11. the tick is mixed into gameHash
12. flinch: damage from a creature, an arrow or lava (or an episode end) breaks out of the tick loop — the rest of the turn is discarded. Starvation damage does not flinch.

Visibility

viewSize = 9. The view is the 9 x 9 square centred on the cog, in world orientation — never rotated to the heading. There is no occlusion: everything in the box is visible, night or day.

The known map is a 64 x 64 array of last-observed terrain plus the tick it was last observed. A cell never in a view stays ? forever. Creatures are never remembered: they appear only in view and in threats, both of which are current.

End conditions

The episode ends at the first of death, all twenty-two unlocked, the turn cap (56), the tick cap (1344), or the wall-clock stop (660 s).

results.reason is a closed enum of exactly three values:

• complete — death, allUnlocked, turnCap or tickCap. A death is complete, not a failure: dying of a zombie bite on night four having unlocked twelve achievements is the game working.
• deadline — the wall-clock stop fired. Everything unlocked so far still scores; the budget guard drops the seat to scripted play two turns before the stop, so this should be unreachable in practice.
• fault — always a defect; CI asserts it never occurs on the fixture seeds.

results.endRule is its own closed enum: death | allUnlocked | turnCap | tickCap | wallClock | fault, and results.deathCause is zombie | skeleton | arrow | lava | starvation | thirst | exhaustion | none.

Scoring

scores[0] = 10000 * achievementsUnlocked + survivalTicks

One more achievement is worth 10 000 and the largest possible survival term is 1344, so achievements always dominate and survival is purely the tie-break. results.win[0] is achievementsUnlocked >= parAchievements (8 in standard, 6 in longnight) — a "did the cog clear the bar" flag, not a duel — and results.winner is 0 when it is true and null otherwise.

The paper's geometric mean, and why it is not this number. Crafter's published score

S = exp( (1/22) * sum_i ln(1 + 100 * p_i) ) - 1

uses p_i, the success rate of achievement i across a run of episodes. A single episode has no success rate — only a boolean per achievement — so S is a cross-episode aggregate and cannot be an episode's score. This coworld therefore reports the integer above per episode, and also reports the raw material S needs: achievementUnlocked[22] and achievementTick[22], in canonical order. tools/crafter_score.py computes S over a directory of results.json files:

python3 tools/crafter_score.py path/to/results/

It needs at least ten episodes to mean anything, and it is NOT what the ladder ranks — the ladder ranks scores[0]. docs/ACHIEVEMENTS.md carries the same statement beside the achievement table.