Anthropic has introduced measures requiring preservation of thinking blocks across turns and added features to reduce chain-of-thought extraction, including through multiple accounts.

“And so where we landed with the last couple models is a few incremental changes to have, like, enforce these preserve thinking blocks across turns, and now, like, starting to be more about, like, across, you know, like, if you're using multiple accounts and things like this, right?”

“Like, how do we make sure that We're, um, ensuring that you aren't able to take advantage of this chain of thought e- extraction with the models. And so we shipped a couple additional features to help with that.”