Boris Cherny, head of Claude Code at Anthropic, said at Y Combinator’s Startup School 2026 last week that he had asked Claude to rewrite Anthropic’s Electron-based Claude desktop app in Swift and verify the result by comparing screenshots pixel by pixel. In an on-stage interview with Diana Hu, Cherny said the task began through Claude Tag, a new Anthropic product that runs Claude in Slack, after he connected a Mac OS runner on GitHub and gave Claude access to an empty Swift code base for a Claude desktop app.

Cherny said the experiment was meant to test what a native version of the Claude desktop app would feel like. His prompt told Claude to run the Electron app in a Mac virtual machine, take screenshots, compare them with the Swift version pixel by pixel, and continue until finished. When Hu asked how long the run had taken, Cherny answered that it was still running and had been going for “a little over two weeks,” or “14 days, 15 days.”

Daring Fireball’s John Gruber argued on August 2, 2026, that the experiment was not a serious way to create a native Mac client for Claude, because copying the current app’s interface would address only implementation issues, not what he described as design problems. Gruber wrote that the Claude Mac app’s issue was not merely that it used Electron (a framework for desktop apps using web technologies), but that its design ignored many Mac UI idioms and was weak on the web, Windows, and Mac.

Gruber said a Swift, AppKit, or SwiftUI version that exactly reproduced the current design would still be less appealing than a better-designed Electron app. He also challenged Cherny’s claim that the current Claude Mac app had become “pretty awesome” after being sluggish and unreliable six months ago, saying his own launch took 30 seconds, including 15 seconds with the spinning beach ball cursor.

Boris Cherny, head of Claude Code at Anthropic, said at Y Combinator’s Startup School 2026 last week that he had asked Claude to rewrite Anthropic’s Electron-based Claude desktop app in Swift and verify the result by comparing screenshots pixel by pixel. In an on-stage interview with Diana Hu, Cherny said the task began through Claude Tag, a new Anthropic product that runs Claude in Slack, after he connected a Mac OS runner on GitHub and gave Claude access to an empty Swift code base for a Claude desktop app.

Cherny said the experiment was meant to test what a native version of the Claude desktop app would feel like. His prompt told Claude to run the Electron app in a Mac virtual machine, take screenshots, compare them with the Swift version pixel by pixel, and continue until finished. When Hu asked how long the run had taken, Cherny answered that it was still running and had been going for “a little over two weeks,” or “14 days, 15 days.”

Daring Fireball’s John Gruber argued on August 2, 2026, that the experiment was not a serious way to create a native Mac client for Claude, because copying the current app’s interface would address only implementation issues, not what he described as design problems. Gruber wrote that the Claude Mac app’s issue was not merely that it used Electron (a framework for desktop apps using web technologies), but that its design ignored many Mac UI idioms and was weak on the web, Windows, and Mac.

Gruber said a Swift, AppKit, or SwiftUI version that exactly reproduced the current design would still be less appealing than a better-designed Electron app. He also challenged Cherny’s claim that the current Claude Mac app had become “pretty awesome” after being sluggish and unreliable six months ago, saying his own launch took 30 seconds, including 15 seconds with the spinning beach ball cursor.