GPT-5.6 Sol
GPT-5.6 Sol
OpenAI's deepest thinker: the one to hand a problem you cannot solve yourself.
Updated
The read
Sol is the top of the GPT-5.6 line and the strongest model here on mathematics and formal reasoning, with a context window past a million tokens. It thinks for a long time before it answers, which is the point and also the bill. On everyday work it is comprehensively out-earned by the cheaper members of its own family, so treat it as a specialist rather than a default.
Where it shines
- Leads the field on mathematics and formal reasoning
- Context window past a million tokens, so whole corpora fit
- Thinking budget is exposed, so you can pay for depth only when you need it
Worth knowing first
- Slow, because the reasoning it is sold on takes real time
- Priced far above its own siblings for work they handle equally well
Index score
88.6
Provisional. This score is read from the product's public capability, not from the one-prompt rebuild the fully reviewed entries went through, so treat it as a placing rather than a verdict.
- Rank
- 02 of 53
- Builds
- LLMs
- Category
- Reasoning
- Output
- Text, code and tool calls over an API
- Pricing
- Paid only
- Best for
- Hard mathematics, proofs and research-grade analysis
Scores are our own editorial judgement, weighted craft 55, speed 10, control 15 and value 20.
Compare it with
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