Rules

Rules

One cog stands in the middle of a green field with nothing in its hands. Underneath it are three more floors of the world it cannot see: stone, then iron depth, then diamond depth. There is nothing alive down there, nothing hunting it, nothing to eat and nowhere to sleep. There are eleven things it has never done, in a fixed order, and each one needs the one before it:

log → planks → crafting table → wooden pickaxe → cobblestone → stone pickaxe → iron ore → furnace → iron ingot → iron pickaxe → diamond.

That is MineRL's ObtainDiamond ladder, rung for rung. The cog has 960 ticks. When they are gone the run stops wherever it stands, and the only thing the league reads is how far up the ladder it got, and how fast.

The world

levelCount = 4, levelSize = 32. Four 32 × 32 grids stacked in z, each indexed (x, y) with x the column 0 … 31 (west → east) and y the row 0 … 31 (north → south); (0, 0) is the north-west corner of every level.

The outermost ring of every level is bedrock — impassable, unmineable, unplaceable — so the cog can never leave the world. cellsTotal is 4096.

A cell holds exactly one block. tier is the lowest pickaxe tier that can mine it (0 = bare hands, 1 = wooden, 2 = stone, 3 = iron, — = never).

Two more glyphs are overlays: v means a shaft goes DOWN from this cell, ^ means one goes UP. @ is the cog and ? is a cell it has never seen. Those seventeen glyphs are the whole vocabulary.

Shafts are the only vertical connection. There is no free falling, no ladders, no climbing a wall. You go down where you cut a hole and you come up the same hole.

Sight

The view is the (2r+1)² square centred on the cog on its current level, world-oriented, no occlusion and no line of sight. r = 5 at the surface (an 11 × 11 window: the sky is open) and r = 2 underground (5 × 5: it is dark down there). A level the cog has never descended to is entirely ? — the diamonds are under a floor you cannot see through.

Recipes

Tools never break. Inventory stacks cap at 64. Crafting an already-owned pickaxe is a free no-op.

Lava

Walking into lava kills the cog instantly and ends the run. Digging down ONTO lava does NOT kill — the floor breaks, the cog stays put, and the cell below becomes permanently known. That asymmetry is deliberate: the seat cannot see through the floor, so a blind descent must never be an instant loss, while a step into a cell it can see is a policy error. Lava becoming newly known within one cell of the cog ends the turn and throws the rest of the plan away — the game's only reactivity, and the only thing worth being reactive to.

Scoring

milestoneScore    = sum over unlocked rungs i of 2^i        (0 .. 2047)
milestonesReached = popcount(milestoneUnlocked)             (0 .. 11)
deepestTick       = the tick the DEEPEST unlocked rung lit
speedBonus        = 0 if nothing unlocked else (maxTicks - deepestTick)
scores[0]         = 1000 * milestoneScore + speedBonus

Higher is better and every term only ever adds: the minimum is 0, the maximum 1000 × 2047 + 959 = 2 047 959. milestoneScore is literally the eleven-bit milestone mask read as an integer, so reaching one rung higher beats every possible combination of the rungs below it — an integer identity, not a convention. maxTicks is always below 1000, so speedBonus can never reach one rung's worth and is purely the tie-break.

results.win[0] is milestonesReached >= parMilestones (6 in standard, 5 in deepcut) and results.winner is 0 when that is true, null otherwise.

Measured but never scored: blocks mined, blocks placed, items crafted, iron smelted, shafts dug, bridges placed, cells seen, deepest level, ticks per level, ore counters, interrupts, primitives executed, actions dropped, macros unreachable, replies repaired. Paying for any of them would let a policy farm the metric by mining and re-placing the same stone forever.

Ending

The episode ends at the first of: the diamond (rung 11 — the run stops in triumph, which also maximises the speed bonus), death in lava, the turn cap (48 turns — the normal way a run ends), the tick cap (960, an independent guard), or the engine's wall-clock stop.

results.endRule is diamond | death | turnCap | tickCap | wallClock | fault. results.reason is the platform's closed enum: complete for the first four (running out of ticks is the game working exactly as designed), deadline for the wall-clock stop, and fault for an unrecoverable server error, which is always a defect.

Variants

Nothing else differs: the ladder, the recipes, the tiers, the action set and the level structure are identical, so milestoneScore means the same thing in both.

A worked results document

{
  "names": ["daveey"], "aliases": ["Alpha"], "scores": [255648],
  "win": [true], "winner": 0, "reason": "complete", "endRule": "turnCap",
  "variant": "standard", "seed": 1734029581,
  "milestoneIds": ["log","planks","crafting_table","wooden_pickaxe",
                   "cobblestone","stone_pickaxe","iron_ore","furnace",
                   "iron_ingot","iron_pickaxe","diamond"],
  "milestonePoints": [1,2,4,8,16,32,64,128,256,512,1024],
  "milestoneUnlocked": [true,true,true,true,true,true,true,true,false,false,false],
  "milestoneTick": [14,17,19,20,21,96,288,312,-1,-1,-1],
  "milestonesReached": 8, "milestonesOf": 11, "milestoneScore": 255,
  "parMilestones": 6, "deepestMilestone": "furnace", "deepestTick": 312,
  "speedBonus": 648, "deathCause": "none", "deepestLevel": 2,
  "ticksPerLevel": [21, 75, 864, 0], "cellsSeen": 412, "cellsTotal": 4096,
  "blocksMined": 184, "blocksPlaced": 2, "itemsCrafted": 9, "ironSmelted": 0,
  "shaftsDug": 2, "bridgesPlaced": 1, "coalMined": 4, "ironOreMined": 2,
  "diamondsMined": 0, "invLog": 0, "invPlanks": 1, "invStick": 2,
  "invCobblestone": 6, "invCoal": 4, "invRawIron": 2, "invIronIngot": 0,
  "invDiamond": 0, "toolsOwned": ["wooden_pickaxe","stone_pickaxe"],
  "interrupts": 3, "primitivesExecuted": 951, "actionsDropped": 2,
  "macrosUnreachable": 1, "repliesRepaired": 0, "finalTick": 960,
  "turnsPlayed": 48, "policyKinds": ["llm"], "llmTurns": [47],
  "fallbackTurns": [1], "deadSeats": [false], "stopDetail": ""
}

Eight unlocked rungs give 1+2+4+8+16+32+64+128 = 255; the deepest is furnace (index 7) at tick 312, so speedBonus = 960 − 312 = 648 and scores[0] = 1000 × 255 + 648 = 255 648; 8 ≥ 6 so win[0] is true and winner is 0; and ticksPerLevel sums to 960 = finalTick. tests/test_minecraft_engine.nim asserts all seven of those identities on every episode it runs.