GPT 5.6 Pro apparently solved all the IMO 2026 problems (competition happened July 15/16 in China). It was done with no human steering and on first attempt. I wasn't involved at all, just ran across this and thought it was impressive (the bar for impressive keeps rising rapidly though).
Anything software engineering related - measurably so - is attributed to Mythos/Fable. The recent wave of security fixes were all attributable to Mythos. I'll leave it at that.
To be clear -- this wasn't meant to be a GPT vs Claude post. This is more that frontier models continue to incrementally get better. No human steering for this level of math is crazy. Go back ten years and ask anyone in the field if this would be possible in ten years -- and you would have gotten "no" from every major AI researcher in existence.