Anthropic's main repository abandons Git: daily merges exceed 30,000, 7 people spent 5 months completing the system migration.

Beating AI News Flash: Claude is writing code so fast that the existing Git system can no longer keep up. In May of this year, Anthropic's main code repository was merging an average of about 2,500 changes per day; by September, that number had exceeded 30,000, more than a 12-fold increase. To address this, seven engineers, with the help of Claude, developed a new version control system called Scion in five months, completed the migration of the main repository, and launched a companion code review tool called Antique.

The history of Anthropic's main branch is now close to 100GB, and the CI system needs to check out about 25 million instances of code per day. The company had deployed hundreds of Git mirror servers, yet still struggled to handle the continuously growing load. Scion switched to on-demand code retrieval, delegating commits, merges, and history queries to the server side, avoiding the need to maintain a massive local repository for every task. Anthropic says the new system requires only 1/200 of the CPU and memory resources of the original Git mirror architecture, reduces code checkout from minutes to seconds, and cuts CI CPU resource requirements by 25%.

Claude also participated in the development of the new system. The team had Claude Mythos Preview rewrite a manually written code migration program, and the result was a reduction in memory usage to 1/20 of the original and a 4-fold increase in running speed. The engineers involved in the project all believe that Claude's coding ability has surpassed their own, but they still handle architectural decisions and reviews, especially to prevent Agents from violating system constraints and over-engineering.

Scion is currently not open source and cannot work offline like Git. Anthropic believes this system is mainly suited for ultra-large repositories with a large number of Agents programming in parallel. If other companies want to adopt it, they would also need to rebuild supporting tools such as code review, search, and CI.

GitLab responded the same day that it is developing a next-generation version management architecture compatible with Git, hoping to preserve existing development workflows while withstanding the pressure brought by large numbers of Agents working in parallel. The project began technical cooperation with Anthropic as early as June of this year and has now entered the private testing phase.