Sam Blackshear, cofounder and chief technology officer of Mysten Labs, announced on Aug. 6 that he is leaving the Sui developer to join Anthropic for defensive security research involving AI. Evan Cheng will assume Mysten’s technical vision while continuing as the blockchain company’s chief executive. Blackshear plans to remain an adviser to Mysten Labs and developers across the Sui ecosystem. Move’s creator said a foundation is being developed and he intends to remain involved afterward. Anthropic is expanding defensive cyber research as frontier models improve software vulnerability discovery capabilities rapidly. Blackshear announced the move in posts on X, saying the role would let him return to hands-on technical work while studying a new problem area. He did not disclose his starting date, reporting line or specific projects at Anthropic. Blackshear said he was motivated by a period in which the “balance of power between attackers and defenders is shifting.” Anthropic’s recent research supports the broader concern, with the company saying Claude Opus 4.6 could identify high severity software vulnerabilities at scale, while its Frontier Red Team studies how advanced models could strengthen defense and offensive activity. Blackshear credited Cheng with recruiting many of Mysten’s strongest technical employees and noted his previous leadership experience at Apple and Meta. Mysten was founded by former Meta engineers and became the original contributor to the Sui layer one blockchain. Mysten Labs partnered with Google Cloud to use generative AI in code development and auditing