cartert27/scion is a repository that clean-room reimplements a version control system in Rust, based on the source control redesign article Anthropic published. It proposes a structure that keeps history and heavy operations on the server and checks out only the paths you need. There is no public release.
This design focuses on agentic coding or CI handling only the files it needs instead of downloading the whole repository every time. The README's own benchmarks were measured on an Apple M4 Pro 24GiB on 2026-10-14. Importing a directory of 1k files took 39.7ms in Scion versus 456.6ms in Git, and a full clone was Git 242.2ms versus Scion 170.1ms. Commits, however, went to Git: Git 33.6ms versus Scion 36.8ms. A direct checkout of the full tree of the real repository t3code dropped from 30.43s to 14.49s, while for a freshly imported repository the checkout was Scion 14.96s and Git 2.90s.
The benchmarks ran on a single machine over loopback, excluding CockroachDB and MinIO latency. Even when checking out 1,521 files with 8 operations, Git took 1.01s and Scion 2.43s. So these results are better read as showing what is possible in a specific local CI workload than as evidence of production performance.