These flagship models have not been free from their own series of hype, as they are set to be the most advanced models yet capable of advanced coding and elaborate research across all fields.

Now, although they are the same model, they come with their different levels of safeguard. Fable 5.1 is generally available, while Mythos 5.1 is available only through trusted partners, as it claims to be unparalleled in its cybersecurity capabilities and support to life sciences.
Here are the key features worth nothing:
Price 
Fable 5.1 will cost significantly less than Fable 5, as the cost will be an estimated 25% less than its predecessor, whereas for highly agentic work it is set to save approximately 45% more.

Data retention;
With the release of Fable 5.1 comes the unveiling of the new system of Enterprise Frontier Safeguards (EFS), designed to give customers complete privacy as it stores data in cloud infrastructure controlled entirely by customers, not Anthropic. Unlike its predecessor, where organizations kept custody of customer data while still allowing cross-session misuse detection and allowed regulation to be more efficient.

Scientific research;
The new models are also very capable in various scientific areas such as designing various affinity binders necessary for drugs to work at lower doses. It was capable of training a neural network to create a higher-resolution elevation map of a third of Venus, improving detail and accuracy over earlier maps. It is safe to say that this AI has far outpaced its predecessors.

Chemical and biological risks
Anthropic also describes Mythos 5.1 as capable of creating chemical and biological weapons. Though its capabilities far surpass its predecessor Mythos 5, it, however, falls short of the next risk tier stated in their responsible scaling policy. It was also made known that the new model will be deployed with the same safeguards that were applied with Mythos 5, which restricts its access to research biology capabilities.

cyber risks;
It was also noted that Mythos 5.1 demonstrated the strongest cyber capabilities of any model released, as it can be used for defensive security work like identifying software capabilities. It was worth noting, however, that the models still fall within the lower category risk in their Frontier Compliance Framework.

These are the parts worth looking out for from the models. Thank you for reading