Anthropic Debuts Claude Fable 5: Unveiling Its Most Advanced AI Model to Date
Anthropic has reached a significant milestone in the deployment of frontier artificial intelligence at scale with the launch of Claude Fable 5—its first publicly available Mythos-class AI model. Released on June 9, 2026, Fable 5 has set the benchmark in AI technology, excelling in various fields including software engineering, knowledge work, scientific research, and vision tasks.
Just two months prior to this, Anthropic had unveiled its restricted Mythos model, which was only accessible to a select group of organizations due to its advanced and potentially hazardous cybersecurity capabilities. In a bid to safely roll out the model to the public, Anthropic developed robust safety classifiers that automatically reroute high-risk queries in areas such as cybersecurity, biology, and chemistry to the safer Claude Opus 4.8, activating in fewer than 5% of sessions.
The pricing for Fable 5 is set at $10 per million input tokens and $50 per million output tokens, which is double the cost of Opus 4.8. However, Pro, Max, Team, and Enterprise subscribers can access it for free until June 22, 2026. A restricted version, Claude Mythos 5, with some safeguards removed, is being concurrently deployed to vetted cyberdefenders through the US government’s Project Glasswing initiative. Stripe reported that during early testing, Fable 5 managed to condense months of engineering work into mere days, achieving approximately 80% on the SWE-Bench Pro agentic coding evaluation.
As Anthropic gears up for a potentially massive IPO, the company’s revenue run rate stands at a reported $47 billion, with a valuation of approximately $965 billion.
Source: CNBC – Anthropic releases Mythos-like AI model to the public