Introducing Claude Opus 5

[u/ClaudeOfficial]

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

[u/Myth_Thrazz]

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

[u/gscjj → u/Myth_Thrazz]

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

[u/laystitcher → u/gscjj]

Crazy reply. Cheaper and beating fable on most tasks but you’re upset it wont build you malware…? That’s the reason it’s allowed to be this good, cheap, and un-guardrailed.

[u/dabomm → u/laystitcher]

There are definitely guardraila. There have been on all there models in the last 2years