Andrew Tulloch, a prominent AI researcher who had recently returned to Meta, left the company by September 10, 2026, to join Anthropic. Tulloch had delayed his earlier departure to oversee Meta's launch of its Muse open-source AI models and assistant.
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Tulloch has been delaying his departure until the company successfully launched its new family of open source AI models and AI assistant, Muse.
Andrew Tulloch, a prominent AI researcher who rejoined Meta less than a year ago, is leaving for Anthropic. An Anthropic spokesperson told Business Insider he will work on the startup’s inference and performance team, optimizing model training and how models respond to users [businessinsider.com#1][thenextweb.com#1][cnyes.com#1]. Semafor first reported his departure from Meta, and Business Insider