Anthropic Releases Claude Fable 5: The First Publicly Available Mythos Model

Anthropic today officially announced the launch of Claude Fable 5, its first Mythos-level model made available to the general public. According to the company, Fable 5 demonstrates "exceptional performance" across software engineering, knowledge work, visual recognition, and scientific research, with overall capabilities surpassing any previously released public model. Anthropic emphasizes that the model has passed safety evaluations and is suitable for a broad range of general-purpose use cases. However, most queries related to cybersecurity, chemistry, and biology will be handled by the more cautious Opus 4.8 model, rather than directly by Fable 5.

Alongside Fable 5, Anthropic also released Mythos 5, an upgraded model deployed through the "Project Glasswing" initiative, replacing the previous Claude Mythos preview. Anthropic claims that Mythos 5 possesses the world's strongest cybersecurity capabilities, with access gradually expanding through a broader "Trusted Access Program." Currently, Mythos 5 is available to all users with Mythos preview access, including Apple. Additionally, Anthropic has rolled out a regular upgrade model, Claude Opus 4.8.

Industry analysts note that by launching two new models simultaneously—the public-facing Fable 5 and the high-end security-focused Mythos 5—Anthropic aims to strike a balance between "general capabilities" and "risk control." The release of Fable 5 marks the first time Mythos-class technology has moved beyond closed testing, while Mythos 5's dedicated security strategy reflects the industry-wide consensus on strict oversight of high-risk domains. With major players like Apple gaining access, the ecosystem impact of this model family warrants continued attention.