Redesigning source control at Anthropic

Anthropic has published an engineering account describing its decision to build a custom alternative to Git, citing a sharp rise in the rate of code changes across the company. The piece, reported by Simon Willison, states that Anthropic averaged roughly 2,500 code changes merged per day in May 2026. By September, that figure had risen to over 30,000 merges per day.

According to the account, this increase in volume over the preceding six months prompted the redesign of the company’s source control infrastructure. Willison’s summary frames the move as a response to constraints that standard Git tooling could not accommodate at this scale of change.

The original Anthropic engineering post, linked from Willison’s site, is titled “Redesigning source control at Anthropic” and was published to the company’s engineering blog. Willison’s post, dated October 13, 2026, excerpts the merge-rate figures directly from Anthropic’s account and characterizes the broader piece as an explanation of “why and how” the company built its replacement system.

No further technical detail from the underlying Anthropic post is included in the available excerpt beyond the cited merge statistics and the framing of the redesign as a response to increased development velocity. The excerpt does not specify the name of the replacement system or additional architectural details beyond what is quoted above.