Describe the effort parameter in Claude Opus 5?

The effort parameter controls how much computational work Claude Opus 5 puts into a request - governing thinking depth as well as the depth of tool calls and arguments, not just visible response length - across levels typically described as low, medium, high, xhigh, and max.

Claude Opus 5 defaults to high effort on the API, and the specific amount of work each level represents was recalibrated relative to Opus 4.8, so a setting carried over unchanged from the prior model won't necessarily produce the same cost or behavior.

Because effort mainly governs thinking and tool-call depth rather than visible answer length, lowering it to save cost won't reliably make responses shorter - controlling response length requires an explicit instruction in the prompt instead.

Invest now in Acorns!!! 🚀
Join Acorns and get your $5 bonus!

Acorns is a micro-investing app that automatically invests your "spare change" from daily purchases into diversified, expert-built portfolios of ETFs. It is designed for beginners, allowing you to start investing with as little as $5. The service automates saving and investing. Disclosure: I may receive a referral bonus.

Invest now!!! Get Free equity stock (US, UK only)!

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.

Webull! Receive free stock by signing up using the link: Webull signup.