“This morning I was managing maybe a few hundred,” he said during the opening session of the 25th annual Fortune Brainstorm Tech conference in Aspen on Monday. “Some days it’s … thousands, or tens of thousands.” This is a big change from even just a year and a half ago, he explained, when developers were running one instance of Claude Code in one terminal window. 

“Fast-forward to today, it looks very different,” he said. “You have a Claude Code, but it has subagents that are other Claudes.” The user is no longer prompting Claude, he added: “It’s actually another Claude that does the prompting.” 

This massive speedup in coding will be as consequential as the printing press, he explained, which was developed by Johannes Gutenberg around 1440 and dramatically lowered the cost of producing books and expanded literacy. Just as the printing press ultimately enabled transformative societal changes such as the Renaissance and Industrial Revolution, Cherny said he believes AI coding assistants are lowering the barriers to software creation and could unlock a similarly profound wave of innovation whose full implications we are only beginning to understand. 

Last week, Anthropic published a blog post titled “When AI Builds Itself,” outlining how it is increasingly using AI systems to help develop future AI models. Taken far enough, and with enough compute, the blog post said such an approach could lead to recursive self-improvement—an AI system capable of autonomously designing, building, and improving its own successors.

Cherny said that with Claude Code writing all the code for Anthropic—leading to an 8x increase in the amount of code written at the company since the beginning of the year—“I think this might be the first product that actually just takes off.” Claude Code is fully writing itself, he said, and is also doing its own security review. 

“We’re starting to get to the point where it has ideas,” he said. “It’s looking at GitHub, it’s looking at [X]; it’s figuring out, ‘What should I build next?’” 

Often, he added, he wakes up in the morning, and Claude has already taken action on a variety of ideas. “It’s quite exciting, because to me it means I can do much more, and the role of a builder is just totally changing,” he said. 

But there are also risks, which Anthropic is taking very seriously, he said. When asked if he was worried about recursive self-improvement, Cherny said yes: “It’s one of the big risks for AI.” 

More from the 25th annual Fortune Brainstorm Tech conference:

Tesla cofounder: ‘We should be really worried’ about the U.S. grid as China speeds ahead in the power race

‘Not an Allbirds Moment’: Xbox’s new CEO says she is grounding the console in gaming roots, not AI

Anduril CEO Brian Schimpf says economic warfare is the ‘new normal’ for military conflicts—and the U.S. needs to get serious