Anthropic replaces git as agent-written code overwhelms merging

Claude now writes code so fast that Anthropic had to rip out git, the tool basically every software company on Earth uses to track changes to its code. Back in May, Anthropic was merging about 2,500 code changes a day. By September it was over 30,000. That's one every three seconds, all day and all night, with Claude driving most of the increase. Git was never built for that. It was designed in 2005 so every developer's copy of a project carries the full history and works offline. That's great if you're a person coding on a plane. Anthropic's main code history is now almost 100 GB, their test systems pull a copy of the code 25 million times a day, and nearly all of those requests come from AI agents and automated jobs that are always connected anyway. Done the normal git way, that adds…

New on our Engineering blog: Creating in-house source control. In May, we merged around 2,500 code changes per day. In September, we merged more than 30,000 per day. As a result, we became bottlenecked by developer infrastructure built for human (rather than agent) scale. Here, we share how we built a new version control system—and fully migrated our monorepo from git—in five months:

SITUATION DETECTED: Anthropic says its code merges per day have grown tenfold and Claude is now able to autonomously iterate on research loops at a speed and scale they have not seen before.

anthropic built their own git. Most interesting mental shift here, and if you buy that changing code happens more and more autonomously, faster*, then this will make a ton of sense: Git was designed so that any client could serve the repo. Fully offline, your *build time* dev stack is never in the hot path for your *run time* deployment. Anthropics new version control system (VCS) does not work offline. There’s a central server which must be reachable for clients to function. They found a bunch of benefits to doing it this way. At first this sounds wild. Today if GitHub is down, you can’t pull or push or merge. Imagine if you couldn’t COMMIT if GitHub was offline. But in a (someday, maybe) future where code changes 1000x per day with no human in the loop, then your VCS is basically part…