30,000 code changes a day: Anthropic replaces Git with its own system, Scion
As AI agents write more and more code, the Git version control system hit its limits at Anthropic. A seven-person team built a replacement in five months – with help from Claude.
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AI developer Anthropic has replaced the widely used Git version control system in its own software development with a home-built system called Scion. The reason is the flood of code generated by AI agents: according to the company, an average of around 2,500 code changes a day were merged in May 2026, and more than 30,000 in September. Automated testing alone checks out around 25 million copies of the code every day; the main branch's history is almost 100 gigabytes.
Git is decentralised – every copy contains the complete archive. At Anthropic's scale, that would mean more than 600 petabytes of traffic a day, according to the company's blog. Scion instead runs commits, merges and version history on the server; machines and agents download only what they need. Its CPU and memory footprint is around 200 times smaller than the previous infrastructure, and code checkouts for tests and research jobs take seconds instead of minutes.
A team of seven built Scion along with a code review tool and completed the switch in five months, with Claude writing large parts of it. Very often, the engineers' role was to tell Claude "no", the blog says. Anthropic does not plan to release Scion as open source – it is not a general replacement for Git, the company says.