OpenAI's GPT-5.6-Sol is finally here, along with the cheaper Terra and Luna.

We’ve seen the early hype as reported on Thursday, but as always that is biased.

As usual, the bulk of this is collecting a gestalt based on reactions. I included everything up to a point, but I got a lot of feedback, so after a while I only took the interesting ones.

Sol and Fable are both excellent models, sir. They both represent big moves forward. There is room in your workflow for both of them.

Sol and Fable are very different, especially when considered as part of their respective packages. I’m considering Sol + Codex (or Work) versus Fable + Claude Code (or Cowork), throughout, in places where you wouldn’t use the chat interface.

In terms of raw intelligence and ‘big model smell,’ and ability to do the hardest things that are intelligence-loaded, Fable still looks like it has a substantial edge. It also seems to be better aligned, or at least more trustworthy as an agent, with less tail risk. I still consider Fable ‘the best’ model, and the one that will require the most aggressive controls.

I enjoy [...]

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Outline:

(02:54) The Official Pitch

(10:06) Sol Proposes A Proof Of The Double Cover Conjecture

(10:49) The Official Benchmarks

(14:26) Vend That Bench

(16:37) Thinking Fast and Slow

(18:35) Other People's Benchmarks

(23:20) Have Robust Backups

(26:33) That's Not What You Were Thinking

(26:59) Helping Hands