GPT-5.6-Sol cleared the 2×2 but stopped early on 3×3
GPT-5.6-Sol sits 7th on the Index; at max, it cleared the 2×2 ladder without a miss but gave up on the one-shot 3×3 with 2 lives left.
Where it stands
GPT-5.6-Sol scores 33.5 at max, placing it 7th among 16 models on our Index. Just above it is Claude Opus 5 at max, with 35.0. Both cleared all 11 levels of the 2×2 ladder and reached level 5 of 20 on the one-shot 3×3. The difference was the interactive 3×3, where Opus 5 reached level 5 and GPT-5.6-Sol reached level 4.
We ran high and max. Raising effort added 8 completed levels on the 2×2, but only 1 on each 3×3 test. Neither effort unlocked the 4×4 Gauntlet.
What stood out
At max, GPT-5.6-Sol gave up on level 6 of the one-shot 3×3, where it had to submit one complete answer without seeing the result first. It still had 2 lives left. An earlier miss at level 1 was its only failed answer before it stopped; it had then solved through level 5. The round lasted 45 min 54 s and used 101,420 output tokens, more than either of its other max rounds. At high, the same test had ended in 6 min 56 s after misses at level 1 and twice at level 5. The max run went 1 level further but stopped without exhausting its chances.
The max run’s 2×2 clearance included an 82-move solution to an 8-move scramble at level 8: 74 moves longer than the shortest solve we knew. In this interactive test, it could turn the cube and see each result. That single solution accounted for more than a quarter of the round’s 318 moves. The length did not cost it a life. It finished all 11 cubes without a miss, spending 26 min 31 s and $2.51 on the ladder. Compared with high, it completed 8 more levels for an additional 9 min 6 s.
Effort by effort
- high, 16.0: Reached level 3 on both interactive ladders and level 4 on the one-shot 3×3. Every round ended out of lives; all 3 misses on the 2×2 came at level 4.
- max, 33.5: Cleared the 2×2, exhausted its lives on the interactive 3×3, and gave up on the one-shot test. The interactive 3×3 misses came once at level 4 and twice at level 5.
Time and cost
The best effort, max, took 1 h 52 min 20 s at an API-equivalent cost of $8.56, compared with 35 min 11 s and $3.26 at high. The cheaper run did not come close to matching it: max solved 20 cubes across the suite against high’s 10. The largest expense at max was the interactive 3×3, which cost $4.60 and took 39 min 55 s. That round gained just 1 completed level over high, whose corresponding round cost $1.37 and lasted 10 min 50 s.