The "think" tool: Enabling Claude to stop and think

Introduced the "think" tool, a mechanism for AI agents to pause during response generation to analyze new information (especially tool outputs) and improve decision-making in complex, policy-heavy, or sequential task environments. Demonstrated significant performance improvements (e.g., 54% relative improvement in pass^1 on the τ-bench airline domain) compared to baseline and extended thinking alone, particularly when combined with domain-specific optimized prompting. The "think" tool is distinct from extended thinking, focusing on in-progress analysis rather than pre-response planning. Implemented and evaluated using τ-bench and SWE-bench benchmarks, showing benefits for tool output analysis, policy adherence, and sequential decision-making, with minimal implementation overhead but increased token usage.