Boris Cherny

“Anthropic deleted 80% of Claude Code's system prompt when Opus 5 shipped — not as a cleanup exercise, but as a deliberate process run at every model release. The result was a smarter-behaving product, not a degraded one.”

“The skill nowadays is less about prompt engineering and more about figuring out how do you give Claude a hard task that seems a little bit too hard. And then how do you make it possible for Claude to verify its work along the way.”

“The dominant mental model in AI product development — accumulate more instructions as models improve — is backwards. The team behind Claude Code discovered that deleting instructions unlocks more capability than adding them.”

“"I don't prompt Claude anymore. I have loops running that prompt Claude and figuring out what to do. My job is to write loops." — Boris Cherny, Head of Claude Code”

“The Claude Code team has formalized a progression of loop types, each one surrendering a different piece of human oversight to the agent: the verification, the stop condition, the trigger, and ultimately the prompt itself.”

“The top patterns (Boris Cherny's verifier loop, 781 likes; build-test-fix pair, 43,587 views) all embed a second model to check output.”

“Claude Code creator Boris Cherny says AI coding is moving from agents that write code to 'loops' in which agents continuously prompt and supervise other agents to improve code bases.”

“Claude Code creator Boris Cherny says AI coding is moving from agents that write code to 'loops' in which agents continuously prompt and supervise other agents to improve code bases, a shift he argues could be as significant as the move from hand-written source code to agentic programming.”

“Boris Cherny - Engineer at Anthropic; creator of Claude Code”

“Every time Boris comes and speaks at YC... one of the things that really stands out is how obsessed he is with simplicity and with just like making the product as small as possible.”