Source Intelligence
Sweep 28 Aug 2026 ยท 16:06Z Build v2.1.251 479 read Stable v2.1.236 Latest v2.1.251 Next v2.1.251 Feeds RSS JSON llms.txt

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overview

models/opus-5/overview

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models/opus-5/overview Changed · +1 / -1 lines

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 ## Overview
 
-Claude Opus 5 is a step-change improvement over Claude Opus 4.8, with the largest gains in deep reasoning, agentic and long-horizon tasks, and test-time compute scaling. This page summarizes everything new in Claude Opus 5, including thinking on by default, mid-conversation tool changes, and a breaking change to when thinking can be disabled.
+Claude Opus 5 is a step-change improvement over Claude Opus 4.8, with the largest gains in deep reasoning, agentic and long-horizon tasks, and test-time compute scaling. This page summarizes everything new in Claude Opus 5, including mid-conversation tool changes and two breaking changes for code running on Claude Opus 4.8: thinking is on by default, and thinking can be disabled only at effort `high` or below.
 
 [What's new in Claude Opus 5](https://platform.claude.com/docs/en/models/opus-5/whats-new-opus-5)