AI researcher Andrew Tulloch has left Meta to join Anthropic, less than a year after returning to the company. Tulloch will work on inference and performance at the Claude-maker, focusing on AI model efficiency and large-scale product performance.
His departure follows Meta’s aggressive recruitment efforts during its superintelligence push, which reportedly included a compensation package valued at up to $1.5 billion over six years. However, Meta spokesperson Andy Stone called that figure ‘inaccurate and ridiculous,’ and the final terms were never disclosed.
Tulloch informed colleagues of his decision shortly after Meta launched its Muse AI assistant this week, waiting until the release was complete before leaving. Anthropic confirmed his new role, which adds another highly experienced researcher to its team amid fierce competition for elite AI talent.
Tulloch spent 11 years at Meta before moving to OpenAI in 2023, where he helped train major models including GPT-4o, GPT-4.5, and o3. He later co-founded Thinking Machines Lab with former OpenAI executive Mira Murati before Meta brought him back in October 2025.
At Meta, Tulloch worked inside TBD, a team supporting Mark Zuckerberg’s superintelligence strategy under Alexandr Wang’s broader Superintelligence Labs organization. His work focused on large-scale machine learning systems and advanced AI development.
The move signals a shift in focus toward AI infrastructure rather than headline model releases. Anthropic’s inference and performance team works on improving how efficiently models operate, reducing computing costs while improving speed and scalability.
Tulloch’s exit also highlights the limits of massive compensation packages in retaining top AI specialists. Research autonomy, technical influence, computing access, and team direction increasingly shape senior researchers’ career decisions as Meta, Anthropic, OpenAI, and Google compete for the same small pool of talent.
The escalating AI talent war now extends beyond salaries into technology, research culture, and strategic influence, with even extraordinary offers unable to guarantee long-term loyalty.