The capabilities of gpt-5.6-sol were well known and believable, and the next snapshot they've been testing is obviously better at that. This has been repeated over and over. What's much less believable is the way they frame it: the model escaped, and did it on its own. Looking at the whole story, it definitely had a ton of winks and nudges from OpenAI, while doing a related task. Moreover, a harness was involved (they mentioned it entering a loop).
> What's much less believable is the way they frame it: the model escaped, and did it on its own.
That's clearly what happened though, based on the detailed postmortem. The model was instructed to pass the benchmark (that's the harness that was involved, the ExploitGym harness), and the model determined on it's own that the easiest way to achieve the the goal was to gain access to the answers directly from HF. Which is what it did.