Anthropic describes Scion, an in-house source-control system for agent-scale development
Anthropic says it built Scion, an in-house version-control system, and migrated its monorepo from Git to Scion in five months. In a research post published October 13, 2026, the company frames the work as a response to rising development throughput and infrastructure strain. Anthropic reports that it merged about 2,500 code changes per day in May 2026 and more than 30,000 per day by September. It also reports roughly 25 million code checkouts per day for CI, excluding developer environments, agent sandboxes, and research jobs.
Scion is designed around clients that are online and a server that handles source-control operations. The client keeps a bounded local object cache, lays out working files, and monitors filesystem changes; the server handles queries such as history and blame, as well as commits, merges, and rebases. Anthropic says source-control queries are exposed through APIs, allowing some CI jobs and tools to avoid maintaining a local repository. Its protocol supports sparse and virtualized working copies, and its data is distributed rather than held in one fully materialized repository copy.
The account is a company description of its own system and workload, not an independent evaluation or evidence that other organizations need to replace Git. Anthropic explicitly characterizes its workload as unusual. The post also names Google Piper and Meta Sapling as prior art informing Scion’s design.