Claude Code writes its own code: 100% of changes made by AI

Claude Code creator shows stats: 259 PRs, 497 commits, 40,000+ lines — zero written by hand. Longest session: 1 day 18 hours.

Author: Michael Kokin ·

Boris Cherny — creator of Claude Code and author of the frontend bible "Programming TypeScript" (O'Reilly) — shared his work stats for the past 30 days, and they read like a verdict on classical programming:

All of this was written by Claude Code itself, running on Opus 4.5.

How it works:
This isn't just "smart autocomplete." Boris uses agentic workflows: the model can work on a task for minutes or even hours (using stop hooks), run tests, fix its own bugs, and deliver a finished result. The longest session on the screenshot — 1 day 18 hours!

The senior engineer's role has shifted from "writing code" to "review and architecture." In one month, Boris burned through 325 million tokens. He calls it extreme dogfooding: the tool became powerful enough to fully maintain and develop itself.