Claude’s extended thinking

Some things come to us nearly instantly: “what day is it today?” Others take much more mental stamina, like solving a cryptic crossword or debugging a complex piece of code. We can choose to apply more or less cognitive effort depending on the task at hand.

Now, Claude has that same flexibility. With the new Claude 3.7 Sonnet , users can toggle “extended thinking mode” on or off, directing the model to think more deeply about trickier questions 1 . And developers can even set a “thinking budget” to control precisely how long Claude spends on a problem.

Extended thinking mode isn’t an option that switches to a different model with a separate strategy. Instead, it’s allowing the very same model to give itself more time, and expend more effort, in coming to an answer.

Pokémon is a fun way to appreciate Claude 3.7 Sonnet’s capabilities, but we expect these capabilities to have a real-world impact far beyond playing games. The model's ability to maintain focus and accomplish open-ended goals will help developers build a wide range of state-of-the-art AI agents.

Claude's new extended thinking capability gives it an impressive boost in intelligence. But it also raises many important questions for those interested in how AI models work, how to evaluate them, and how to improve their safety. In this post, we share some of the insights we've gained.

As well as giving Claude the ability to think for longer and thus answer tougher questions, we’ve decided to make its thought process visible in raw form. This has several benefits:

But a visible thought process also has several downsides. First, users might notice that the revealed thinking is more detached and less personal-sounding than Claude’s default outputs. That’s because we didn’t perform our standard character training on the model’s thought process. We wanted to give Claude maximum leeway in thinking whatever thoughts were necessary to get to the answer—and as with human thinking, Claude sometimes finds itself thinking some incorrect, misleading, or half-baked thoughts along the way. Many users will find this useful; others might find it (and the less characterful content in the thought process) frustrating.