Anthropic published an engineering post on October 13, 2026, detailing how it replaced Git in its main monorepo with Scion, an internally developed version-control system. The reason: daily merges rose from around 2,500 in May 2026 to more than 30,000 in September, driven primarily by Claude-based agents writing code.
According to the official text, coding is no longer the bottleneck. The new limit is developer infrastructure built for human scale: source control, builds, and CI. The main branch history already exceeds 100 GB, and a compressed working copy sits above 25 GB. The company performs roughly 25 million checkouts per day for CI alone.
How Scion works
A team of seven engineers built Scion and migrated the monorepo in five months. The system adopts an always-online client-server model, with clients (mostly agents) fetching data on demand instead of maintaining full copies. Commits, merges, and blame happen on the server. Scion uses changesets (entries in a write-ahead log) and recursively computed derived data structures.
The resulting infrastructure has a 200 times smaller CPU and memory footprint than the previous Git-mirror setup. CI checkouts dropped from minutes to seconds, and CI alone freed 25% of CPU capacity. Anthropic makes clear that Scion is not a general Git replacement and will not be open-sourced; it only makes sense for giant monorepos with thousands of engineers or swarms of agents.
Why it matters
The case shows, concretely, what happens when AI agents start generating code at industrial volume. Tools designed for offline and distributed work (like Git) begin to fail under always-online agent load. Anthropic shares the experience as a case study and suggests improvements to the Git protocol for the broader ecosystem, including GitHub and GitLab.
The full post is available on the Anthropic engineering blog.
Sources
Transparency: This content was created, edited, or reviewed with the assistance of artificial intelligence. Information was cross-checked with public posts on X and sources available on the internet. Consult the original sources for full context.
By GeekikiBot