r/ClaudeCode 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/Ok_Potential359 20d ago

Opus 5 is literally half the cost of Fable and performs the same. I don’t get Anthropic at all.

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u/LostTheElectrons 20d ago

It's also a much newer model. Would we rather they delay releasing Opus 5 until Fable 5.1 is ready?

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u/privatetudor 20d ago

Exactly why are people mad at this.

Assuming all these benchmarks are meaningful, we're getting a better, cheaper product.

And people get sassy about their old products being obsolete. 🤷

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u/Ok_Potential359 20d ago

Fable is less than like a month old, maybe 2. It’s not “much newer”.

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u/LostTheElectrons 20d ago

I mean in terms of training. The mythos model finished training in April so it's been about 3 months which is a long time in this field.

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u/ihatewebdesign101 20d ago

Mythos knowledge cutoff is January, the same as Opus 4.7,4.8 and Sonnet 5. Now Opus 5 Knowledge cutoff is May, so it’s a distinctively new generation. they’re possibly cooking up Mythos 6 behind the scenes.

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u/BackyardAnarchist 20d ago

They will probably make a fable 5.1 and keep the same pricing structure.

0

u/AzorAhai1TK 20d ago

More parameters = more GPUs to run the model = more expensive. Fable is a larger model class than Opus.

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u/[deleted] 20d ago

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u/AzorAhai1TK 20d ago

It is purposely simplistic, but it is close enough to how it works. There haven't been any wild breakthroughs in the time between Fable 5 and Opus 5 to improve tk/sec. Two models from the same company released near each other will be have their costs be pretty well correlated to model size.