Extended Thinking
Also: extended thinking mode, Claude thinking mode
Extended thinking is a mode where Claude works through a problem step-by-step before giving its final answer. You see its reasoning process — including the parts where it changes its mind or catches an error. It takes longer and costs more tokens, but produces meaningfully better results on hard problems: complex analysis, multi-step planning, tricky reasoning tasks. Turn it on when accuracy matters more than speed.
Articles
When to use extended thinking — and when it's a waste
Extended thinking makes Claude noticeably better on hard problems. But most tasks don't need it, and using it everywhere will slow you down and cost more.
When to use Extended Thinking — and when not to
Extended Thinking gives Claude time to reason through hard problems before answering. Here is what it is actually good for, and what it adds over standard Claude.