> Extended thinking with tool use (beta): Both models can use tools—like web search—during extended thinking, allowing Claude to alternate between reasoning and tool use to improve responses.

I'm happy that tool use during extended thinking is now a thing in Claude as well, from my experience with CoT models that was the one trick(tm) that massively improves on issues like hallucination/outdated libraries/useless thinking before tool use, e.g.

o3 with search actually returned solid results, browsing the web as like how i'd do it, and i was thoroughly impressed – will see how Claude goes.