Anthropic today announced the launch of Claude Fable 5, a Mythos-class model that it says is safe for general use.
According to Anthropic, Fable 5’s capabilities exceed those of any model it has made generally available, and Fable has demonstrated “outstanding performance” in software engineering, knowledge work, vision, scientific research, and more. It outperforms Opus models on longer and more complex tasks. Fable 5 can operate autonomously longer than any previous Claude model.
Fable 5 is released with conservative safeguards to prevent it from being misused in areas like cybersecurity. Questions on certain topics will instead be answered in Opus 4.8, with protections expected to trigger in less than five percent of sessions on average. Most queries related to cybersecurity, chemistry, and biology will get answers from Opus 4.8 instead of Fable 5.
Anthropic is also releasing Claude Mythos 5 for a small group of cyber defenders and infrastructure providers. It uses the same underlying model as Fable 5, but with some safeguards removed. Mythos 5 is rolling out through the Glasswing project as an upgrade to Claude Mythos Preview. Anthropic says Mythos 5 has the most powerful cybersecurity capabilities of any model in the world, with access set to expand through a broader Trusted Access program.
Fable 5 and Mythos 5 are available at $10 per million input tokens and $50 per million output tokens, less than half the price of the Claude Mythos preview. Mythos 5 is available to those who have access to Mythos Preview, and that includes Apple. Apple is one of the partners of Anthropic’s Glasswing project.
Claude Fable 5 is included in the Pro, Max, Team and Enterprise per seat packages from today until June 22. On June 23, the model will be removed from these plans and its use will require usage credits. When Fable 5 capacity is sufficient, Anthropic plans to add it back to subscription plans.
