Boris Cherny on Trying to Get Claude Code to Rewrite the Claude App

Boris Cherny, head of Claude Code at Anthropic, was interviewed by Diana Hu on stage at Y Combinator’s Startup School 2026 last week. Starting around 20:30 in the video , he briefly discussed directing Claude to perform difficult tasks: Cherny: I think 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. Then how do you make it possible for Claude to verify its work along the way? The verification is probably the single most important thing that people do not get right, largely. One example of this is people were — we have this desktop app for Claude and it’s built using Electron. We’ve made it quite fast. Now it’s a pretty awesome experience. Six months ago it was sluggish and it wasn’t very reliable. Now it’s pretty awesome. It’s the thing that most of the team uses. As an experiment, I wanted to see what it would feel like if it was native. So what I did is I started a Claude Tag session. Claude Tag is a new product we have. It’s just Claude running in Slack. My first question was, “Hey Tag, do you have access to a Mac OS runner on GitHub?” It said no. Then I hooked up a runner. So it was able to start a Mac virtual machine using GitHub. My second question was, I created this empty code base that was a Claude desktop app rewritten in Swift. I asked, “Can you access this code base?” It said no. Then I gave it access and it was like, “Okay, great. Now I have access.” Then I said, “Okay, now what I want you to do is I want you to rewrite the Electron app in Swift.

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