Lesley

Founder| Forward Deployed Engineer | prev: Sr. AI Engineer | Philosophy background | AI Safety & Security

[Lesley @cyberblocked]

https://t.co/EzW83inGTa

[ClaudeDevs @ClaudeDevs]

https://t.co/v694m8Eaj6

[Gael Breton @GaelBreton]

Fable is the first model to go like:

Bro I know what I’m doing. Stay out of it please.

[Burak @xburak]

Unpopular opinion:

Vibe coding only works if you already know how to code.

[Lesley @cyberblocked]

Can confirm this makes a huge difference in your workflows 🔥

[Thariq @trq212]

I’ve found the most important part of working with Fable is discovering my own unknowns so I can prompt it better, heres how I do that.

[Lesley @cyberblocked]

@trq212 This is incredibly useful. Thanks for sharing!

[DROID @droidbuilds]

it’s official, vibe coding done by legend himselff😂

[Thariq @trq212]

I've heard a lot of questions about Fable's availability on subscription plans.

While it will come off subscriptions after July 7th, we aim to restore Fable as a standard part of our subscriptions as soon as capacity allows, as we mentioned in our original blog post.

[David Ondrej @DavidOndrej1]

sorry for not tweeting much

Fable 5 is back

it's time to build

[Sick @sickdotdev]

“Let me talk to my team”

The team:
- Me
- Claude code
- 4 coffees
- Macbook Pro

[Claude @claudeai]

Following conversations with the US government, we’ve updated our cybersecurity safeguards.

The vast majority of coding work is unaffected.

In the near term, the new safeguards will flag a slightly higher fraction of harmless requests than the previous Fable safeguards; we’re working to refine these over the coming weeks. Users will be clearly notified when a request is flagged, and they’ll instead receive a response from Opus 4.8.

Our biology and chemistry classifiers are unchanged from our initial launch. These are still broader than we would like; they trigger fallbacks to Opus 4.8 on basic biology-adjacent questions. Improvements to these classifiers are landing soon.

[uaghazade @uAghazadae]

@claudeai finally!! going to use Fable to center a div

[Lesley @cyberblocked]

@claudeai @AnthropicAI YESS!!! 👏

[Claude @claudeai]

Fable 5 is back.

[Lesley @cyberblocked]

@Polymarket Always wash your produce people!

[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://t.co/VHyum831ri

[Lesley @cyberblocked]

@gregisenberg Agreed.

[Lesley @cyberblocked]

@AnthropicAI I can’t wait!!!

[Anthropic @AnthropicAI]

We’ve received notice that the Department of Commerce has lifted export controls on Claude Fable 5 and Mythos 5.

We'll begin restoring access tomorrow, and will share an update soon.

We’re grateful to our users for their patience, and to everyone who worked with us on redeploying the models.

[Lesley @cyberblocked]

Fable 5!!!!!! @AnthropicAI

[Justine Moore @venturetwins]

Bringing the Fable 5 news to every group chat