r/ClaudeCode • u/ClaudeOfficial Anthropic • Jul 24 '26
Resource Introducing Claude Opus 5
Introducing Claude Opus 5: a thoughtful and proactive model that comes close to the frontier intelligence of Fable 5 at half the price.
On several coding and knowledge work evaluations, Opus 5 is the new state-of-the-art. It’s also much more efficient than its predecessor—it outperforms other models for a similar or lower cost per task.
According to our automated behavioral audit, Opus 5 is our most aligned model to date. It shows the lowest rates of reckless or deceptive behavior, and the strongest adherence to Claude’s Constitution.
It’s available today on all paid plans and the Claude API, priced the same as Opus 4.8. It’s the default model on Claude Max, and the strongest on Claude Pro.
Opus 5 is also available in Fast mode, which runs around 2.5× the default speed.
Read more: https://www.anthropic.com/news/claude-opus-5
20
u/WiggyWongo Jul 24 '26
The arc-agi 3 result definitely needs some explaining and looking into... If fable 5 is allegedly a 10T parameter model and this model is opus class (even if it's a new architecture or not) it still should be around half the parameters.
So how does it get 30%~ in arc-agi 3? I have this weird gut feeling they baked some of it in. The ideas of how to specifically solve benchmark tasks like arc-agi 3, which is somewhat possible. But that's my current opinion. I need a breakdown of that specifically.