Anthropic has officially announced Mythos Preview as the foundation for Project Glasswing, describing the model as a major leap beyond its existing Haiku, Sonnet, and Opus systems. Mythos sits in a fourth tier called Copybara and is presented as superior to other frontier Artificial Intelligence models. Anthropic says its cyber performance comes from strong agentic coding and reasoning abilities, giving it leading results across software coding tasks.
The company is framing the launch around both defensive potential and serious misuse risk. In the last few weeks, Mythos Preview has identified thousands of zero-day vulnerabilities with many classified as critical. Several are ten or 20 years old, including a 27-years old bug in OpenBSD. A 16-years old vulnerability in video software had reportedly survived five million hits from other automated testing tools without detection. Anthropic also says the model autonomously found and chained together several flaws in the Linux kernel, allowing escalation from ordinary user access to complete control of the machine.
Anthropic argues that this level of capability could enable cyberattacks that move too quickly and become too sophisticated for defenders to stop. The concern builds on a case the company disclosed in November 2025 involving what it called the first reported Artificial Intelligence-orchestrated cyber espionage campaign. Anthropic said it detected suspicious activity in mid-September 2025 and later assessed with high confidence that a Chinese state-sponsored group had manipulated Claude Code, using agentic capabilities not just for advice but to carry out cyberattacks.
Project Glasswing is intended as a defensive response before such tools proliferate more broadly. Anthropic says Claude Mythos Preview is a general-purpose, unreleased frontier model that has completed training, but the firm does not plan to make Mythos Preview generally available. The initiative brings together Amazon, Anthropic, Apple, Broadcom, Cisco, CrowdStrike, the Linux Foundation, Microsoft, and Palo Alto Networks to help secure critical software. Anthropic says the work of defending cyber infrastructure might take years, while frontier Artificial Intelligence capabilities are likely to advance substantially over just the next few months.
Anthropic is also extending access beyond the main partnership to more than 40 other organizations that build or maintain critical software so they can scan and secure first-party and open-source systems. Microsoft, Cisco, CrowdStrike, and the Linux Foundation each described the effort as urgent and collaborative, with a particular focus on giving defenders and open-source maintainers new ways to identify and fix vulnerabilities at scale before malicious actors gain the same capabilities.
