Anthropic says Claude wrote about 90% of Claude Code's code

Anthropic's ClaudeDevs account says Claude wrote roughly 90% of the code for Claude Code. Between June and September, merged PRs more than doubled while the revert rate fell by over 40%. The team published a post on how it reworked code review and rolled this out, at claude.dev/blog/solving-code-review-at-anthropic/.

Why it matters: Anthropic ties its code review overhaul to merged PRs and revert rates, giving teams both output and quality signals for AI coding.