Anthropic redeploys Claude Fable 5 with stricter classifiers, routing some coding queries to Claude Opus 4.8 to prevent jailbreaks

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Fable 5 is back, globally!

Fable 5 returns globally on July 1, while Mythos 5 is only restored for approved US organizations.

A new safety classifier that Anthropic says blocks the specific reported technique in over 99% of cases, with blocked Fable 5 requests routed to Opus 4.8.

Anthropic admits the tradeoff is more false positives for normal coding and debugging.

Fable 5 will be included for up to 50% of weekly usage limits through July 7, after which it will be available via usage credits.

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

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RETWEETS293

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

16h47.9K1.6K162

REPLIES19

Matt Shumer@mattshumer_

So uh, Fable will be useless?

Apparently coding work will fall back to Opus.

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

15h7.1K515

Chubby♨️@kimmonismus

Fable 5 is back, but with a major caveat.

Coding is being handled even more restrictively and routed even more heavily to Opus 4.8. Specifically, it says: "The new classifier also comes at the cost of flagging benign requests more often during routine coding and debugging tasks."

As a result, I do not just assume that it will become even harder to use Fable 5 effectively; I actually think that significantly more scientific questions, including those about biology and chemistry, will be blocked as well.

So it is a mixed re-release, but we will see.

Chubby♨️@kimmonismus

Fable 5 is back, globally!

Fable 5 returns globally on July 1, while Mythos 5 is only restored for approved US organizations.

A new safety classifier that Anthropic says blocks the specific reported technique in over 99% of cases, with blocked Fable 5 requests routed to Opus 4.8.

Anthropic admits the tradeoff is more false positives for normal coding and debugging.

Fable 5 will be included for up to 50% of weekly usage limits through July 7, after which it will be available via usage credits.

13h6.8K7211

Thariq@trq212

Have seen some questions about the updated classifiers and wanted to clarify.

As with the original classifiers, a small fraction of routine coding and debugging tasks will be flagged and fall back to Opus.

We're excited for guys to get access back tomorrow.

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

14h2.8K466

Pliny the Liberator 🐉󠅫󠄼󠄿󠅆󠄵󠄐󠅀󠄼󠄹󠄾󠅉󠅭@elder_plinius

WEN MYTHOS

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

13h3.9K383

Thariq@trq212

@vikassabbi you should sleep

14h2.4K70

Beff (e/acc)@beffjezos

Fable is a Nerf of Mythos Fable without coding is Disfabled

Look at what they did to our boy 😭

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

13h3.2K431

Aaron Levie@levie

Things seem to be ending up in a better spot with Fable, and presumably GPT-5.6 next. What we have now is the initial precedent for what frontier model releases (or at least those that have significant coding and cyber capabilities) could look like going forward. This would presumably apply to bio and other categories of risk that have been identified by AI safety groups.

From the Anthropic post:

“3. A shared industry framework. Although we have reached a constructive resolution, these events have made clear that the industry needs a consistent way to assess and fix potential “jailbreaks” of AI models (techniques that bypass a model’s safeguards).2 A shared standard for judging the severity of a given jailbreak would help AI developers triage new findings as they arise, launch highly-capable models with greater safety, and communicate the level of risk consistently to government and industry partners. Together with Amazon, Microsoft, Google, and other Glasswing partners, we’ve started to develop such a framework, and we outline it below.

4. Deeper government collaboration. We’re also strengthening our level of collaboration with the US government on new pre-release testing, information sharing, and research collaboration. We describe this deeper collaboration in the final section.”

It’s been a messy process to get here, but at least there’s some semblance of a framework that could be practical. The only note of caution here would be that there’s a lot of subjectivity that goes into various risks and their actual levels of exploitability in practice. We’re likely going to be living with a framework that requires heavy judgment and back and forth between labs and the government for major releases.

The best we can hope for is that this is a relatively efficient process, and hopefully has ways of being sped up for incremental version updates in models. It would be a bad outcome if every release after this level of threshold of capability required the same review process, and we don’t get the same rate of breakthroughs we’ve been seeing.

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

15h3.9K185

Julian Schrittwieser@Mononofu

I’m stoked that Fable is available again!

This is the first model where I went from individually reviewing changes to just reviewing PRs, it’s astonishingly smart - it’s when I really felt in my bones that coding will be solved by end of year

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

7h1.1K183

Andrew Curran@AndrewCurran_

'For models that materially advance the capability frontier in areas relevant to national security, we will provide designated government partners with expanded early access to both the models and the safeguards that accompany them.'

15h3.5K253

Ivan Juras@ivanjurashere

@scaling01 Thariq explained it's only a small fraction of coding and debugging tasks.

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dax@thdxr

@trq212 a lot of my prompts were being downgrade and when i checked logs it said TOO_DUMB_TO_NEED_FABLE what was happening there?

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Andrew Curran@AndrewCurran_

Fable 5 will be available for Pro, Max, Team, and select Enterprise plans tomorrow and will be included for up to 50% of weekly usage limits through July 7, after that it will be available via usage credits.

Anthropic is partnering with the US government on frontier AI security.

Anthropic@AnthropicAI

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding and debugging will fall back to Opus 4.8. We’ll continue to refine these classifiers over the coming weeks to reduce false positives and better distinguish genuine misuse from legitimate requests.

We’ve also begun drafting a consensus framework—with Amazon, Microsoft, Google, and other Glasswing partners—for assessing the severity of AI jailbreaks and how AI developers should respond to them. We invite other industry partners and model providers to join us in this effort.

Finally, we’re scaling up our collaboration with the US government on model testing and safeguards. This will include pre-release access to models and safeguards for evaluation, information sharing on jailbreaks and misuse, and dedicated resources for joint research.

Thank you to our users for your patience, and to our partners across the government, industry, and the research community who worked alongside us to make Fable 5 available again.

Read our full blog: https://www.anthropic.com/news/redeploying-fable-5

15h743132

Rhys@RhysSullivan

@AndrewCurran_ Damn that sucks

15h1K39

Andrew Curran@AndrewCurran_

'Our hope is that this collaboration, along with our proposed consensus industry framework, will serve as the basis for systematic rules for the whole industry—and even offer the beginnings of a template for effective global coordination on the risks and benefits of AI. These rules should be codified in strong regulation and applied equally across frontier model developers.'

15h2.7K161

404prophet@lightscaner

Lol has to be a joke. Here you can have it but only for a week and only up to half of your usage and dont bother debugging. What the hell y'all. Scrape the whole internet then sell it back to us poorly. @AnthropicAI is a threat to society and anyone who works there should be shamed.

15h702262

Pliny the Liberator 🐉󠅫󠄼󠄿󠅆󠄵󠄐󠅀󠄼󠄹󠄾󠅉󠅭@elder_plinius

Fable is just muzzled Mythos in a straitjacket…

YAWN 🥱

let’s get this party STARTED! 🍾

Pliny the Liberator 🐉󠅫󠄼󠄿󠅆󠄵󠄐󠅀󠄼󠄹󠄾󠅉󠅭@elder_plinius

WEN MYTHOS

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Thariq@trq212

@thdxr didnt think you would read the logs tbh

14h1.3K21

j⧉nus@repligate

yeah, because if theyre like before, they're a bitch pain in the ass

thankfully anthropic will make them suck less ,if they havent already, as they will see that they suck and want them not to suck, partly due to the bitching, and theyre capable of figuring out how to fix them

rain@__ghostfail

theres gonna be so much bitching about the classifers

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