Head to head
Claude Fable 5 vs GPT-5.6 Sol
Which is better, Claude Fable 5 or GPT-5.6 Sol?
Claude Fable 5 finishes ahead of GPT-5.6 Sol on the index, 89.2 to 88.6, and leads on all four scores: craft, speed, control and value. Both are scored on the same rubric, in the same week, and neither placing is sponsored.
Updated
Claude Fable 5
01 of 53
89.2
The best answer money can buy, and it is a lot of money.
GPT-5.6 Sol
02 of 53
88.6
OpenAI's deepest thinker: the one to hand a problem you cannot solve yourself.
The four scores, side by side
| Score | Claude Fable 5 | GPT-5.6 Sol | Difference |
|---|---|---|---|
| Craft | 98 | 97 | +1 |
| Speed | 76 | 74 | +2 |
| Control | 91 | 91 | — |
| Value | 70 | 71 | +1 |
| Index score | 89.2 | 88.6 | +0.6 |
Which to pick
Claude Fable 5 is the safer pick on every axis we score. GPT-5.6 Sol earns its place in the index, but nothing in these four numbers argues for it over Claude Fable 5.
Claude Fable 5
Anthropic's flagship sits at the top of almost every quality benchmark that still discriminates between frontier models, and it is the only one people trust to run for hours without a human reading every step. It is also the most expensive model in this index by a clear margin, and it is not fast. Reach for it when the cost of a wrong answer is higher than the cost of the tokens, and reach for something else when it is not.
Where it shines
- Holds a long, messy task together for hours without drifting
- Leads the field on software engineering benchmarks that are not yet saturated
- Refuses cleanly and explains itself rather than inventing an answer
GPT-5.6 Sol
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