Overview
- Anthropic disclosed Tuesday that it completed a five-month migration of its main code repository from Git to an internal system called Scion and published an engineering post describing the change.
- Daily merges rose from roughly 2,500 in May 2026 to over 30,000 by September 2026, a surge the company attributes to its Claude coding agents producing a large share of merged production code.
- Scion shifts work from local clones to server-side operations so agents and automated jobs fetch only needed data, which Anthropic says cuts CPU and memory for mirroring by about 200× and makes checkouts roughly 100× faster.
- A seven-person team built Scion and related tools in-house, freeing about 25% of CI CPU capacity and relying on engineers to continue human review of agent-generated changes and to correct agent shortcuts.
- Anthropic says Scion is aimed at extremely large, agent-heavy repositories, plans to share its approach with GitHub, GitLab and open-source projects, and warns broad adoption would require major toolchain changes.