Anthropic built its own git replacement for AI-scale coding. But you can’t have it.

Anthropic has built its own version control system because, at its scale, git started to crack. The new tool, called Scion, was made to keep up with a surge in code merges that jumped from 2,500 a day in May to more than 30,000 a day in September 2026.

The company says Claude helped create the bottleneck and then helped solve it. Anthropic was already using Claude Mythos Preview and Claude Tag internally when the pressure became obvious, and it says the same AI coding speed that made the problem worse also let a small team move fast on the fix.

Scion is now the system behind Anthropic’s monorepo, and the company says the migration took five months. It also claims the new setup cuts CPU and memory use by 200 times compared with its old git-mirroring infrastructure, while CI and research jobs can check out code two orders of magnitude faster.

The reason Anthropic gives for building Scion is blunt: its developer stack was built for human pace, not machine pace. It says Scion avoids some of git’s offline assumptions, offers always-on access and API-based source control, and scales horizontally instead of forcing the company to keep hundreds of mirrors in sync.

But none of that means anyone else gets it. Anthropic says Scion is too tied to its own workflow, too costly in token use for most companies, and too far from git to be an easy drop-in replacement. It does want to work with GitHub, GitLab and the open source community on some of the ideas, though that’s a long way from handing over the actual system.