Anthropic Daily Code Merges Exceed 30,000 by September

Anthropic’s engineers increased their daily code merges from about 2,500 in May 2026 to more than 30,000 by September, as Claude authored most of the code entering the company’s codebase.

The figures represent growth of more than 12 times in four months. More than 80% of merged code was authored by Claude as of May, compared with a low-single-digit share before Claude Code entered research preview in February 2025.

That increase shifted the main challenge from writing software to processing the volume of machine-generated changes. Source control, builds and continuous integration became infrastructure bottlenecks as engineers reviewed, merged, tested and deployed code at a faster pace.

Anthropic built Scion, an in-house version-control system, and completed the migration of its monorepo from Git in five months. The system was developed as the company’s existing development infrastructure struggled to handle the higher volume of activity.

The typical Anthropic engineer merged eight times as much code per day in the second quarter of 2026 as in 2024. Lines of code measure output volume, however, and do not establish whether the resulting software is better.

Claude also reviews proposed changes for bugs, security flaws and other defects before they are merged. A retrospective analysis found that applying automated review to every code change would have caught roughly one-third of bugs associated with earlier incidents.

The development process now places engineers in a supervisory role: They set objectives, assess results and direct revisions while AI agents write and execute code. One anonymous Anthropic employee described the change by saying, “I started leaning hard into Claudifying about a year ago. I’m now been ~5 months since I last wrote any code myself.”

The rapid increase in machine-generated changes makes the capacity of source control, build systems and testing pipelines a central part of Anthropic’s software strategy.