Although we never had a Claude Opus 5.1. Fable went 5 → 5.1 and Opus went 5 → 5.5.
I assume Fable 5.1 is the first re-tuned (is there a better term for this?) version of Fable 5 and Opus 5.5 is the first re-tuned version of Opus 5, and maybe the Opus one just came out better for some reason?
> If they had 6, don't you think they'd be serving it?
No I do not. OpenAI has some hidden model that's apparently 5x or so better at certain benchmarks than GPT 6 but they're not and have no plans to release it. It is increasingly likely that these AI companies keep the best models for themselves and then release smaller, cheaper distilled models for everyone else, especially since the AI companies are vertically integrating into many fields.
You’re assuming the goal of the big AI companies is to serve models for money. That is not the goal. They have a lot of incentives not to share their best models.
I assume Fable 5.1 is the first re-tuned (is there a better term for this?) version of Fable 5 and Opus 5.5 is the first re-tuned version of Opus 5, and maybe the Opus one just came out better for some reason?