Let’s tell you What’s new about Claude Fable 5Anthropic’s new public model for its artificial intelligence chat, It is the first model of the new Mythos class, which already when it launched its preview version two months ago did so saying that it was so powerful that they would limit its power.
Anthropic has launched two new models, the Claude Mythos 5 which will be available only to “a small group of cyber defenders and infrastructure providers”, and a Claude Fable 5 more adapted for mainstream users. It is a model with all the capabilities of Mythos Preview, but with security measures so that it is not used for bad things.
And precisely because it is the model that is reaching users, it will be precisely Claude Fable 5 that we are going to focus on. we will give you a list with everything that changes so you know what it’s like to use compared to the previous version.
Claude Fable 5 news
- Mythos-level capabilities for everyone: Fable 5, along with Mythos 5, is the most powerful AI model in history. Their capabilities are enormous, with performance that makes them lead the test benches. It is the first that allows you to use the capabilities of Mythos 5, and the jump from Claude Opus 4.8 is truly surprising, leaving GPT-5.5 and Gemini 3.1 Pro far behind.
- Longer freelance work: Fable 5 can work autonomously for longer than their predecessors. This makes it possible to tackle longer and more complex tasks that could not be sustained before.
- A big leap in programming: Programming is another aspect where this model has improved the most. Anthropic highlights the case of Stripe, which during initial tests performed a complete migration of a 50 million line code base in Ruby in one day, a job that would have taken a human team more than two months.
- More efficiency: Fable 5 is also more efficient in token consumption than previous Claude models, good news for teams who want to get the most out of it.
- Improvements in knowledge work: Fable 5 shows solid performance on complex analytical tasks. Anthropic claims to outperform the competition in senior-level reasoning, with notable improvements in reasoning about documents, interpreting graphs and tables, and problem solving.
- Great improvement in vision tasks: This new model can extract concrete figures from detailed scientific figures and reconstruct the source code of a website based solely on screenshots. For example, he was even able to beat Pokémon FireRed based on vision alone, while previous models had trouble playing even with assistive tools.
- Better memory and long context: The model is able to not get lost over millions of tokens, maintaining focus on the context, and improving memory. Something perfect for longer and more complex tasks.
- Maintains its barriers against misuse: Anthropic also says its new model keeps the level of misaligned behavior. This means that deceiving him or trying to get him to cooperate in misuse is still just as difficult.
- Safeguards with forwarding to Opus 4.8: Fable 5 is based on Mythos 5, which Anthropic said was so powerful it was scary. That is why it comes quite well-equipped and with many security measures. For example, if it detects that we are asking something “dangerous”, it avoids the question and even forces the use of an inferior model, Claude Opus 4.8.
- New data retention policy: For Mythos-class models, including Fable 5, Anthropic requires 30-day data retention for security monitoring purposes, both on its own and third-party surfaces. Of course, they say that they will not use that data to train new models or for anything that is not related to security. After 30 days, it will delete all data from our conversations in almost all cases.
- Price and availability: Fable 5 costs $10 per million tokens in and $50 per million tokens out, less than half of what Claude Mythos Preview cost. Developers can use it in the Claude API with the identifier claude-fable-5. Plus, it’s included at no extra cost until June 22 for Pro, Max, Team, and Enterprise subscribers. Of course, starting June 23, it will require usage credits until the capabilities of the company’s servers allow it to be incorporated as standard in payment plans in the future.
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