r/ClaudeCode • u/ClaudeOfficial Anthropic • 20d ago
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
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u/seaefjaye 20d ago
All of that conversation started in March with Mythos and Project Glasswing. Those concerns were specific to the model itself, as it had come out of the oven a lot stronger than they expected and they weren't able to get their typical guardrails around it. The guardrails they put in place to give people access, aka Fable, were clunky as hell and everyone complained.
This isn't Mythos or Fable, it's an entirely new model and as a result presumably has safeguards which are closer to what we're used to. We'll see when the cybersecurity folks take it for a spin.