Sui blockchain co-creator and Mysten Labs chief technology officer Sam Blackshear announced on August 6 that he is leaving the company to join Anthropic, where he will work on defensive security research. Blackshear shared the news in a post on X, saying the move lets him return to hands-on technical work while exploring a new problem area. He did not share a start date, reporting structure, or specific project details.
From Mysten Labs to Anthropic
Blackshear co-founded Mysten Labs in 2021 alongside a team of former Meta engineers who had worked on the Diem blockchain project. Mysten Labs went on to build Sui, a Layer 1 blockchain that launched its mainnet in 2023 and has since grown into one of the more actively used networks in the space.
| Date | What happened |
|---|---|
| Before 2021 | Blackshear is an engineer at Novi, Meta’s crypto unit, where the future Mysten Labs founders worked on the Diem blockchain and the Move programming language |
| 2021 | He co-founds Mysten Labs with other former Novi staff, including CEO Evan Cheng, and becomes its CTO |
| 6 December 2021 | Andreessen Horowitz (a16z) announces its investment in Mysten Labs, reported at $36 million |
| 3 May 2023 | Sui mainnet launches, supported by more than 100 validators |
| 4 January 2025 | SUI reaches its all-time high of $5.35 |
| 6 August 2026 | Blackshear announces on X that he is leaving Mysten Labs to work on defensive security research at Anthropic |
| 16 October 2026 | About 4.12 billion of the 10 billion maximum SUI supply is in circulation |
As CTO, Blackshear was one of the most visible technical figures behind Sui’s architecture and development direction. His exit marks a departure from one of the more prominent technical leadership roles in the Layer 1 blockchain space.
In his announcement, Blackshear said the shift in the “balance of power between attackers and defenders” influenced his decision to move into security research. That framing reflects his own assessment rather than a measured industry finding.
Anthropic has published research suggesting its Claude Opus 4.6 model can identify high-severity software vulnerabilities at scale, an area the company has flagged as increasingly relevant to cybersecurity. Anthropic’s Frontier Red Team studies how advanced AI models could affect both defensive and offensive security work, tracking how the same capabilities that help find vulnerabilities could also be used to exploit them.
What This Means for Sui Users and Developers
Blackshear’s departure leaves a leadership gap at Mysten Labs during a period when AI-driven security research is becoming a bigger focus across the tech industry. As CTO, he was closely involved in decisions around Sui’s core protocol upgrades, developer tooling, and technical roadmap, so his exit raises questions about who takes over that responsibility in the near term. Sui developers and holders will want to watch for any statement from Mysten Labs on succession plans or changes to technical direction.
Mysten Labs Yet to Name a New CTO
Mysten Labs has not yet named a replacement CTO or commented publicly on the transition. The company has multiple senior technical leaders who could step into an expanded role, but no succession plan has been announced. How quickly Mysten Labs addresses the leadership change, and whether it names an interim or permanent replacement, will signal how much disruption the departure causes to Sui’s development roadmap.
We’ll continue tracking this story as it develops, along with other breaking crypto news our readers are following this week.
What this means for you: If you hold or follow Sui, here’s the bottom line: Blackshear helped build the technology behind the network, so his exit does not touch the coins or tokens you already hold, but it is worth watching since it could shape how fast Sui rolls out new features or fixes issues going forward.
