Anthropic builds Git replacement Scion, already migrated

Anthropic frames the problem as a shift in where software development actually stalls. With AI writing more code, it says coding itself is no longer the bottleneck; the human-oriented infrastructure around it — managing, building and continuously integrating code — now is. The numbers it publishes back that up: its monorepo's main-branch history alone reaches 100GB, over 25GB even compressed for a working copy, roughly 25 million checkouts a day for CI, and Git traffic above 600PB a day.

Scion was designed around that scale. Clients no longer store a full copy and instead download data from the server as needed, and computation such as commits and merges happens server-side, cutting client-side work. Anthropic reports large speed-ups over Git on several operations, and says an early AI-assisted rewrite of the system cut memory use to one-twentieth while raising processing speed 4 times.

Anthropic is candid that this is not a product for everyone. Scion is tuned to its own internal circumstances and may not help other organizations, and moving off Git would also require replacing related systems like code review and code search. Still, it says it expects "Git becoming a bottleneck" to become more common over the next 6 to 12 months and argues it would be inefficient for every company to solve that alone — hence its stated intent to work with the Git community, GitHub and GitLab to carry Scion's best ideas back into Git.