Mysten Labs co-founder and chief technology officer Sam Blackshear is leaving the Sui developer to join Anthropic, where he will work on defensive security research.
Blackshear announced the move in posts on X on 6 August, saying the position would allow him to return to hands-on technical work while exploring a new area of research. He did not say when he will start, who he will report to or which specific projects he will join at Anthropic.
He said his decision was influenced by a period when the “balance of power between attackers and defenders is shifting.” That is Blackshear’s assessment rather than a measured industry finding, although recent work published by Anthropic reflects similar concerns.
Anthropic has said its Claude Opus 4.6 model was able to identify high-severity software vulnerabilities at scale. The company’s Frontier Red Team programme is also examining how advanced artificial intelligence models could be used to improve both defensive and offensive cyber capabilities.
Blackshear said he would remain a close adviser to Mysten Labs and would continue responding to Sui ecosystem developers who ask for his help. Mysten’s leadership page listed him as co-founder and CTO before the announcement, alongside co-founder and chief executive Evan Cheng.
According to Blackshear, Cheng will now define Mysten’s technical vision. The company, however, has not issued a separate statement outlining a succession plan, and it has not confirmed whether it will appoint a new CTO or divide Blackshear’s responsibilities among existing executives.
The departing executive praised Cheng for recruiting many of Mysten’s leading technical employees and highlighted his previous leadership roles at Apple and Meta. Blackshear also thanked Mysten Labs employees and the wider Sui community.
Mysten Labs was established by former Meta engineers and became the original contributor to Sui, a layer one blockchain.
The company has already explored the use of artificial intelligence in blockchain development and security. A partnership with Google Cloud involved generative AI tools trained on Move, as well as an automated auditing system intended to find weaknesses in Move, Rust, TypeScript and Solidity code.
That work placed AI-assisted development and blockchain security at the centre of Mysten’s strategy before Blackshear’s move to Anthropic.
Move creator to remain involved
Blackshear created Move while working at Meta and has spent more than eight years developing the programming language. Sui Foundation materials describe Move as a smart contract language built around ownership, scarcity and safer management of digital assets.
Its resource model is designed to prevent certain categories of programming error. Sui’s implementation adds an object-focused structure and programmable transaction blocks.
Blackshear also said a Move Foundation is “in the works” and that he hopes to continue contributing to it. He gave no launch date and provided no details about its governance model, leadership, funding or intended scope.
It is not yet clear whether the proposed foundation would oversee Move’s development across multiple blockchains or concentrate on a narrower set of technical standards. A separate organisation could offer a neutral forum for language development, documentation and governance, but no formal body or timetable has been announced.
The need for broader security measures was highlighted by the $260m Cetus Protocol exploit. Researchers said the affected contracts carried out permitted instructions, while the underlying failure involved pricing and liquidity controls operating above the programming-language layer.
The incident demonstrated that smart contract security depends not only on the language used, but also on protocol design, monitoring and the ability to respond operationally to attacks.
Anthropic expands cyber security research
Blackshear joins Anthropic as the company increases its work on AI-enabled cyber threats. In June, Anthropic said it had examined 832 accounts connected to malicious activity and mapped their behaviour using the MITRE ATT&CK framework.
The company said it had banned the accounts and identified AI assistance at several stages of the attack process, including reconnaissance, malware development and evasion.
Anthropic is also investigating how its models can support defenders. Its Project Glasswing brought together about 50 partners to search critical software for vulnerabilities. In separate research with Pacific Northwest National Laboratory, Anthropic used Claude during simulated attacks on a water treatment system.
Those results were reported by the company and do not establish that defenders will consistently remain ahead of attackers. They do, however, indicate the research environment Blackshear is entering.
His experience in programming languages, static analysis and automated bug detection is closely aligned with that work. Before joining Mysten Labs, he worked on Move and associated security tools at Meta. Sui’s official archive identifies Blackshear as Move’s creator and a former principal engineer at the company.
Anthropic has not yet explained which team Blackshear will join or detailed his research agenda. Mysten Labs has not confirmed a replacement CTO. Developers will also be watching to see whether the proposed Move Foundation receives formal leadership, funding and a launch timetable.
