SpaceChem Bench: Suspicious Behavior

organic_2 Hard Sensing Single-reactor Flidais · SpaceChem Bench report →

Inputs: α Carbon (C), β Δ-Dihydrogen (ΔH2). Output: ψ Δ-Pseudopolyethylene ((Δ2C2H4)n) ×10. Features: Bonders (4), Sensor, Large output (4×8).

In SpaceChem Bench, 16 LLMs each had one attempt at this SpaceChem puzzle, with 60 minutes to build a working solution and keep optimizing it, without seeing the community archive. 3 of 16 models solved it. No model found a new Pareto-frontier point beyond the frozen community archive.

3 / 16models solved it
2,415best LLM cycles (1,101 community)
0new frontier points

Records

ScoreCommunity bestBest LLMModel
Cycles1,1012,415GPT-6.1 Sol · +119%
Reactors11GPT-6 Astra Ties record
Symbols2745GPT-6.1 Sol · +67%

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

Lower is better ↙
Loading interactive Pareto explorer…
Community archiveModel frontier pointNew frontier point
Select a point with the mouse or keyboard to inspect its scores and reactor blueprint.

Search over time

Loading puzzle trajectories…

Every model

ModelSolvedBest cyclesBest reactorsBest symbolsNew frontier points
01GPT-6.1 SolYes2,415145—
02Gemini 4 ArgonYes2,698151—
03GPT-6 AstraYes3,275161—
04DeepSeek V4.1 FlashNo————
05Fable 5.1No————
06GLM-5.3No————
07GPT-6 LunaNo————
08Gemini 3.8 FlashNo————
09Grok 4.7No————
10Haiku 5.5No————
11Kimi K3.1 ProNo————
12MiMo-V2.6-ProNo————
13Muse Spark 1.3No————
14Muse Wonder 1.0No————
15Opus 5.5No————
16Sonnet 5.5No————

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.

GPT-6.1 Sol Fewest cyclesFewest reactors

2,415 cycles · 1 reactor · 46 symbolsorganic_2.2415-1-46.txt on GitHub

Layout

α β ψ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 ↓ → → ↑ → ↑ ↓ ← ↓ ← ↓ ↑ → ↑ ← ↑ ↓ → ↓ ← S← DROP S← GRAB IN β SYNC FLIP→ B− B+ B+ G/D FLIP→ SYNC CCW CCW IN α SYNC GRAB DROP ?H→ OUT ψ SYNC CW SYNC B+ B+ FLIP← DROP

Running in the game

GPT-6.1 Sol solution running on organic_2 in SpaceChem
SpaceChem Community Edition export (organic_2.2415-1-46.txt)
SOLUTION:Suspicious Behavior,Player,0-0-0
COMPONENT:'drag-largeoutput-reactor',2,0,''
MEMBER:'instr-start',180,0,128,5,1,0,0
MEMBER:'instr-start',180,0,32,2,1,0,0
MEMBER:'feature-bonder',-1,0,1,1,5,0,0
MEMBER:'feature-bonder',-1,0,1,2,5,0,0
MEMBER:'feature-bonder',-1,0,1,7,0,0,0
MEMBER:'feature-bonder',-1,0,1,7,1,0,0
MEMBER:'feature-sensor',-1,0,1,6,7,0,0
MEMBER:'instr-arrow',90,0,64,1,1,0,0
MEMBER:'instr-arrow',0,0,64,1,5,0,0
MEMBER:'instr-arrow',0,0,64,2,0,0,0
MEMBER:'instr-arrow',-90,0,64,2,5,0,0
MEMBER:'instr-arrow',0,0,64,3,0,0,0
MEMBER:'instr-arrow',-90,0,64,3,3,0,0
MEMBER:'instr-arrow',90,0,64,8,0,0,0
MEMBER:'instr-arrow',180,0,64,8,1,0,0
MEMBER:'instr-arrow',90,0,64,9,0,0,0
MEMBER:'instr-arrow',180,0,64,9,1,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-sync',-1,0,128,1,2,0,0
MEMBER:'instr-bond',-1,1,128,1,4,0,0
MEMBER:'instr-bond',-1,0,128,1,5,0,0
MEMBER:'instr-toggle',0,0,128,2,3,0,0
MEMBER:'instr-sync',-1,0,128,2,5,0,0
MEMBER:'instr-rotate',-1,1,128,3,2,0,0
MEMBER:'instr-rotate',-1,1,128,3,3,0,0
MEMBER:'instr-input',-1,0,128,4,1,0,0
MEMBER:'instr-sync',-1,0,128,6,0,0,0
MEMBER:'instr-grab',-1,2,128,7,0,0,0
MEMBER:'instr-sensor',0,0,128,8,0,0,1
MEMBER:'instr-output',-1,0,128,9,0,0,0
MEMBER:'instr-arrow',90,0,16,1,1,0,0
MEMBER:'instr-arrow',-90,0,16,1,6,0,0
MEMBER:'instr-arrow',0,0,16,3,0,0,0
MEMBER:'instr-arrow',-90,0,16,3,2,0,0
MEMBER:'instr-arrow',180,0,16,5,1,0,0
MEMBER:'instr-arrow',-90,0,16,5,2,0,0
MEMBER:'instr-arrow',90,0,16,6,0,0,0
MEMBER:'instr-arrow',0,0,16,6,1,0,0
MEMBER:'instr-arrow',90,0,16,7,1,0,0
MEMBER:'instr-arrow',180,0,16,7,2,0,0
MEMBER:'instr-input',-1,1,32,1,1,0,0
MEMBER:'instr-toggle',0,0,32,1,2,0,0
MEMBER:'instr-sync',-1,0,32,1,3,0,0
MEMBER:'instr-bond',-1,0,32,1,4,0,0
MEMBER:'instr-grab',-1,0,32,1,5,0,0
MEMBER:'instr-rotate',-1,0,32,1,6,0,0
MEMBER:'instr-sync',-1,0,32,3,0,0,0
MEMBER:'instr-bond',-1,0,32,4,0,0,0
MEMBER:'instr-bond',-1,0,32,5,0,0,0
MEMBER:'instr-grab',-1,2,32,5,1,0,0
MEMBER:'instr-grab',-1,1,32,6,0,0,0
MEMBER:'instr-toggle',180,0,32,6,1,0,0
MEMBER:'instr-grab',-1,2,32,7,1,0,0

GPT-6.1 Sol Fewest symbols

2,457 cycles · 1 reactor · 45 symbolsorganic_2.2457-1-45.txt on GitHub

Layout

α β ψ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 ↓ → → ↑ → ↑ ← ↓ ← ↓ ↑ → ↑ ← ↑ ↓ → ↓ ← S← DROP S← GRAB IN β SYNC FLIP→ B− B+ B+ G/D FLIP→ SYNC CCW CCW IN α SYNC GRAB DROP ?H↓ OUT ψ SYNC CW SYNC B+ B+ FLIP← DROP

Running in the game

GPT-6.1 Sol solution running on organic_2 in SpaceChem
SpaceChem Community Edition export (organic_2.2457-1-45.txt)
SOLUTION:Suspicious Behavior,Player,0-0-0
COMPONENT:'drag-largeoutput-reactor',2,0,''
MEMBER:'instr-start',180,0,128,5,1,0,0
MEMBER:'instr-start',180,0,32,2,1,0,0
MEMBER:'feature-bonder',-1,0,1,1,5,0,0
MEMBER:'feature-bonder',-1,0,1,2,5,0,0
MEMBER:'feature-bonder',-1,0,1,7,0,0,0
MEMBER:'feature-bonder',-1,0,1,7,1,0,0
MEMBER:'feature-sensor',-1,0,1,6,7,0,0
MEMBER:'instr-arrow',90,0,64,1,1,0,0
MEMBER:'instr-arrow',0,0,64,1,5,0,0
MEMBER:'instr-arrow',0,0,64,2,0,0,0
MEMBER:'instr-arrow',-90,0,64,2,5,0,0
MEMBER:'instr-arrow',0,0,64,3,0,0,0
MEMBER:'instr-arrow',-90,0,64,3,3,0,0
MEMBER:'instr-arrow',180,0,64,8,1,0,0
MEMBER:'instr-arrow',90,0,64,9,0,0,0
MEMBER:'instr-arrow',180,0,64,9,1,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-sync',-1,0,128,1,2,0,0
MEMBER:'instr-bond',-1,1,128,1,4,0,0
MEMBER:'instr-bond',-1,0,128,1,5,0,0
MEMBER:'instr-toggle',0,0,128,2,3,0,0
MEMBER:'instr-sync',-1,0,128,2,5,0,0
MEMBER:'instr-rotate',-1,1,128,3,2,0,0
MEMBER:'instr-rotate',-1,1,128,3,3,0,0
MEMBER:'instr-input',-1,0,128,4,1,0,0
MEMBER:'instr-sync',-1,0,128,6,0,0,0
MEMBER:'instr-grab',-1,2,128,7,0,0,0
MEMBER:'instr-sensor',90,0,128,8,0,0,1
MEMBER:'instr-output',-1,0,128,8,1,0,0
MEMBER:'instr-arrow',90,0,16,1,1,0,0
MEMBER:'instr-arrow',-90,0,16,1,6,0,0
MEMBER:'instr-arrow',0,0,16,3,0,0,0
MEMBER:'instr-arrow',-90,0,16,3,2,0,0
MEMBER:'instr-arrow',180,0,16,5,1,0,0
MEMBER:'instr-arrow',-90,0,16,5,2,0,0
MEMBER:'instr-arrow',90,0,16,6,0,0,0
MEMBER:'instr-arrow',0,0,16,6,1,0,0
MEMBER:'instr-arrow',90,0,16,7,1,0,0
MEMBER:'instr-arrow',180,0,16,7,2,0,0
MEMBER:'instr-input',-1,1,32,1,1,0,0
MEMBER:'instr-toggle',0,0,32,1,2,0,0
MEMBER:'instr-sync',-1,0,32,1,3,0,0
MEMBER:'instr-bond',-1,0,32,1,4,0,0
MEMBER:'instr-grab',-1,0,32,1,5,0,0
MEMBER:'instr-rotate',-1,0,32,1,6,0,0
MEMBER:'instr-sync',-1,0,32,3,0,0,0
MEMBER:'instr-bond',-1,0,32,4,0,0,0
MEMBER:'instr-bond',-1,0,32,5,0,0,0
MEMBER:'instr-grab',-1,2,32,5,1,0,0
MEMBER:'instr-grab',-1,1,32,6,0,0,0
MEMBER:'instr-toggle',180,0,32,6,1,0,0
MEMBER:'instr-grab',-1,2,32,7,1,0,0