Anthropic built its own source control system Scion

Anthropic reportedly moved its monorepo off Git to a custom version control system called Scion. Daily merged changes rose from about 2,500 in May to over 30,000 by September, making Git an infrastructure bottleneck. Scion keeps code server-side, lets clients fetch only needed files and commits directly on the server without a separate push.

• Daily merges grew from ~2,500 in May to 30,000+ by September
• Code stays server-side; clients fetch only the files they need
• Commits are made on the server without a separate push step
• The migration covers the monorepo, not all Anthropic repositories