Intel / article

The "think" tool: Enabling Claude to stop and think in complex tool use situations

Source: anthropic.com
Author: Anthropic
Date: Published Mar 20, 2025

Context

Anthropic's think-tool article now recommends extended thinking instead of a dedicated think tool in most cases. That December 15, 2025 update changes how developers should read the earlier examples: they document a technique tested with Claude 3.7, rather than a blanket recommendation for later systems.

The original tool simply records a reasoning step. It gives the space to review newly returned information, identify missing facts and check applicable rules before continuing. It does not fetch evidence or change a database. The enduring design problem is allowing an agent to reconsider its next action after receiving information; the article's update says the model's integrated thinking capability is generally the preferred way to provide that space.

Terms in this piece · Glossary

AI agent — An AI system that doesn't just answer once but works toward a goal in a loop — taking actions, reading the results, and deciding what to do next.
tool use — A model's ability to call external functions — run code, search the web, edit files — instead of only generating text.

Key quotes

“Airline domain : The "think" tool with an optimized prompt achieved 0.570 on the pass^1 metric, compared to just 0.370 for the baseline—a 54% relative improvement;”
Anthropic

“Extended thinking is all about what Claude does before it starts generating a response. With extended thinking, Claude deeply considers and iterates on its plan before taking action. The "think" tool is for Claude, once it starts generating a response, to add a step to stop and think about whether it has all the information it needs to move forward.”
Anthropic

“Our experiments ( n =30 samples with "think" tool, n =144 samples without) showed the isolated effects of including this tool improved performance by 1.6% on average (Welch's t -test: t (38.89) = 6.71, p < .001, d = 1.47).”
Anthropic

“We found that, when they were long and/or complex, including instructions about the "think" tool in the system prompt was more effective than placing them in the tool description itself.”
Anthropic

“Extended thinking capabilities have improved since its initial release, such that we recommend using that feature instead of a dedicated think tool in most cases.”
Anthropic

Read the source www.anthropic.com