It was in the announcement, too. I’m 99% sure they edited it after they changed their mind, because I knew about it from reading that, and never opened the model card.
On the earliest web archive snapshot I can find [0], I do not see any mention of the safeguard/sabotage under discussion [1].
And to be clear, this isn't the safeguard where the model is explicitly downgraded to Opus, but rather where the Fable/Mythos model's "effectiveness" is transparently "limited" via "prompt modification, steering vectors, or parameter-efficient fine-tuning (PEFT)".
Indeed. I can’t find it, but I swear I knew after reading the announcement, without opening the model card. It stood out because it was so weird. Maybe they changed it before the first snapshot, maybe something else happened, I don’t know.
And to be clear, this isn't the safeguard where the model is explicitly downgraded to Opus, but rather where the Fable/Mythos model's "effectiveness" is transparently "limited" via "prompt modification, steering vectors, or parameter-efficient fine-tuning (PEFT)".
[0]: https://web.archive.org/web/20260609173222/https://www.anthr...
[1]: https://simonwillison.net/2026/Jun/10/if-claude-fable-stops-...