Today, Anthropic released Claude Opus 5. It replaces Claude Opus 4.8 as the Opus-tier flagship. Pricing is unchanged at $5 per million input tokens and $25 per million output tokens.
The Anthropic team positions Opus 5 as approaching the intelligence of Claude Fable 5 at half the price. It is now the default model on Claude Max and the strongest model on Claude Pro.
What actually changed at the API level
Three changes are quite important before any benchmark does:
Thinking is on by default. On Opus 4.8, requests ran without thinking unless you set thinking: {"type": "adaptive"}. On Opus 5 the same request thinks, and the effort parameter controls depth. Because max_tokens caps thinking plus response text, existing values need review.
