SpaceChem Bench: Prelude to a Migraine

sensing_2 Medium Sensing Single-reactor Alkonost Random inputs · SpaceChem Bench report →

Random inputs: α Oxygen (O) / Oxygen (O2). Output: ψ Oxygen (O) ×20. Features: Bonders (4), Sensor, Random inputs.

In SpaceChem Bench, 16 LLMs each had one attempt at this SpaceChem puzzle, with 40 minutes to build a working solution and keep optimizing it, without seeing the community archive. 16 of 16 models solved it. Together they found 1 new Pareto-frontier point beyond the frozen community archive.

16 / 16models solved it
67best LLM cycles (67 community)
1new frontier point

Records

ScoreCommunity bestBest LLMModel
Cycles6767Gemini 4 Argon Ties record
Reactors11DeepSeek V4.1 Flash Ties record
Symbols77Fable 5.1 Ties record

Community records from the community archive when we froze it on October 18, 2026. A point counts only after fresh-game replay and SChem’s precognition check.

Pareto frontier

Pareto explorer

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Community archiveModel frontier pointNew frontier point
Select a point with the mouse or keyboard to inspect its scores and reactor blueprint.

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Every model

ModelSolvedBest cyclesBest reactorsBest symbolsNew frontier points
01Gemini 4 ArgonYes67171
02Fable 5.1Yes6817—
03GPT-6 AstraYes7317—
04GPT-6.1 SolYes7317—
05Opus 5.5Yes7617—
06DeepSeek V4.1 FlashYes8718—
07Gemini 3.8 FlashYes8717—
08Sonnet 5.5Yes8817—
09Grok 4.7Yes8917—
10Muse Wonder 1.0Yes8917—
11Kimi K3.1 ProYes9617—
12GLM-5.3Yes9918—
13Haiku 5.5Yes115112—
14Muse Spark 1.3Yes12517—
15MiMo-V2.6-ProYes184110—
16GPT-6 LunaYes210113—

Best scores can come from different solutions. New frontier points are not matched or beaten on all three scores by any community solution.

Best model solutions

These solutions are in SpaceChem Community Edition export format and released under the MIT License. All of this puzzle’s model solutions are on GitHub and Hugging Face.

Gemini 4 Argon Fewest cycles

67 cycles · 1 reactor · 16 symbolssensing_2.67-1-16.txt on GitHub

Layout

α β ψ ω 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 → ← → ← S↑ S→ G/D G/D B− OUT ψ ?O← IN α IN α B− OUT ψ G/D G/D B−

Running in the game

Gemini 4 Argon solution running on sensing_2 in SpaceChem
SpaceChem Community Edition export (sensing_2.67-1-16.txt)
SOLUTION:Prelude to a Migraine,Player,0-0-0
COMPONENT:'drag-advanced-reactor',2,0,''
MEMBER:'instr-start',-90,0,128,3,5,0,0
MEMBER:'instr-start',0,0,32,0,1,0,0
MEMBER:'feature-bonder',-1,0,1,3,1,0,0
MEMBER:'feature-bonder',-1,0,1,4,1,0,0
MEMBER:'feature-bonder',-1,0,1,5,1,0,0
MEMBER:'feature-bonder',-1,0,1,6,1,0,0
MEMBER:'feature-sensor',-1,0,1,1,1,0,0
MEMBER:'instr-arrow',0,0,64,1,1,0,0
MEMBER:'instr-arrow',180,0,64,6,1,0,0
MEMBER:'instr-grab',-1,0,128,1,1,0,0
MEMBER:'instr-bond',-1,1,128,2,1,0,0
MEMBER:'instr-sensor',180,0,128,3,1,0,8
MEMBER:'instr-input',-1,0,128,3,4,0,0
MEMBER:'instr-bond',-1,1,128,5,1,0,0
MEMBER:'instr-grab',-1,0,128,6,1,0,0
MEMBER:'instr-arrow',0,0,16,1,1,0,0
MEMBER:'instr-arrow',180,0,16,6,1,0,0
MEMBER:'instr-grab',-1,0,32,1,1,0,0
MEMBER:'instr-output',-1,0,32,2,1,0,0
MEMBER:'instr-input',-1,0,32,3,1,0,0
MEMBER:'instr-bond',-1,1,32,4,1,0,0
MEMBER:'instr-output',-1,0,32,5,1,0,0
MEMBER:'instr-grab',-1,0,32,6,1,0,0

Fable 5.1 Fewest reactors

68 cycles · 1 reactor · 14 symbolssensing_2.68-1-14.txt on GitHub

Layout

α β ψ ω 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 → ← → ← S→ OUT ψ S↑ GRAB GRAB IN α OUT ψ B− B− OUT ψ DROP DROP

Running in the game

Fable 5.1 solution running on sensing_2 in SpaceChem
SpaceChem Community Edition export (sensing_2.68-1-14.txt)
SOLUTION:Prelude to a Migraine,Player,0-0-0
COMPONENT:'drag-advanced-reactor',2,0,''
MEMBER:'instr-start',0,0,128,2,1,0,0
MEMBER:'instr-start',-90,0,32,1,3,0,0
MEMBER:'feature-bonder',-1,0,1,4,1,0,0
MEMBER:'feature-bonder',-1,0,1,5,1,0,0
MEMBER:'feature-bonder',-1,0,1,6,1,0,0
MEMBER:'feature-bonder',-1,0,1,9,7,0,0
MEMBER:'feature-sensor',-1,0,1,3,7,0,0
MEMBER:'instr-arrow',0,0,64,1,1,0,0
MEMBER:'instr-arrow',180,0,64,6,1,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-input',-1,0,128,3,1,0,0
MEMBER:'instr-bond',-1,1,128,4,1,0,0
MEMBER:'instr-bond',-1,1,128,5,1,0,0
MEMBER:'instr-grab',-1,2,128,6,1,0,0
MEMBER:'instr-arrow',0,0,16,1,1,0,0
MEMBER:'instr-arrow',180,0,16,6,1,0,0
MEMBER:'instr-grab',-1,1,32,1,1,0,0
MEMBER:'instr-output',-1,0,32,2,1,0,0
MEMBER:'instr-output',-1,0,32,3,1,0,0
MEMBER:'instr-output',-1,0,32,5,1,0,0
MEMBER:'instr-grab',-1,2,32,6,1,0,0

Opus 5.5 Fewest symbols

159 cycles · 1 reactor · 7 symbolssensing_2.159-1-7.txt on GitHub

Layout

α β ψ ω 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 → ← S→ S↓ IN α GRAB DROP OUT ψ B−

Running in the game

Opus 5.5 solution running on sensing_2 in SpaceChem
SpaceChem Community Edition export (sensing_2.159-1-7.txt)
SOLUTION:Prelude to a Migraine,Player,0-0-0
COMPONENT:'drag-advanced-reactor',2,0,''
MEMBER:'instr-start',0,0,32,8,3,0,0
MEMBER:'instr-start',90,0,128,0,0,0,0
MEMBER:'feature-bonder',-1,0,1,5,1,0,0
MEMBER:'feature-bonder',-1,0,1,6,1,0,0
MEMBER:'feature-bonder',-1,0,1,7,1,0,0
MEMBER:'feature-bonder',-1,0,1,1,7,0,0
MEMBER:'feature-sensor',-1,0,1,3,5,0,0
MEMBER:'instr-arrow',0,0,64,0,1,0,0
MEMBER:'instr-input',-1,0,128,0,1,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-arrow',180,0,64,6,1,0,0
MEMBER:'instr-grab',-1,2,128,6,1,0,0
MEMBER:'instr-output',-1,0,128,5,1,0,0
MEMBER:'instr-bond',-1,1,32,9,3,0,0