The Surprise Hit That Made Anthropic Into an AI Juggernaut

Even Anthropic Chief Executive Officer Dario Amodei was surprised by the initial level of enthusiasm for what became the startup’s next breakthrough product. For months, engineers across the company flocked to an internal AI coding tool called Claude Code that was originally developed as a side project by Boris Cherny, then an employee in an experimental division of Anthropic that he compares to Bell Labs.

“I remember Dario asking, like, ‘Hey, are you forcing engineers to use this? Why is everyone using it?’” Cherny recalled in a recent interview. Actually, Cherny explained, all he had to do was give his ...