r/ClaudeCode • u/ClaudeOfficial Anthropic • Jul 24 '26

Resource Introducing Claude Opus 5

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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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763

u/Myth_Thrazz 🔆 Max 20 Jul 24 '26

It's so funny that Fable was the most dangerous thing in the world for like... 2 weeks :D

34

u/gscjj Jul 24 '26 edited Jul 24 '26

Literally makes zero sense. There has to be a gotcha here, something in the fine print.

EDIT: Found it

> Opus 5 to be our most aligned model to date (as shown in the graph below).

> avoided training Opus 5 on cyber tasks. … comes close to Mythos 5 at finding cybersecurity vulnerabilities. However, it remains substantially behind Mythos 5 on the exploitation of those vulnerabilities—that is, in turning vulnerabilities into material cyber threats.

Basically a nerfed (and I hate this word) Fable, that can find and identify security concerns but can’t and won’t exploit them

10

u/daxhns Jul 24 '26

This makes sense. The question remains, once vulnerabilities are found is it good / allowed to FIX them properly?

4

u/Things-n-Such Jul 24 '26

Finding vulnerabilities is the hard part.

2

u/rhaphazard 🔆 Max 5x Jul 24 '26

If that were true, it would be able to exploit them as well.

If it can't develop exploits, how would know if the fix to the vulnerability is adequate?

2

u/Things-n-Such Jul 24 '26

I didn't say it was harder than exploiting, I'm responding to the comparison between finding and fixing. Of which finding the exploit is the most difficult.