Summary
Theo of t3.gg digs into an Anthropic article describing a new in-house source control system built for the age of coding agents. Anthropic reports growing from about 2,500 merged changes per day in May to more than 30,000 per day in September, and says its developer infrastructure, designed for humans, had become the bottleneck.
The video explains why Git’s assumptions, such as expensive code, human review, and careful control over merges, strain under heavy parallel work by many people and many agents. Theo also criticizes GitHub’s reliability, citing external estimates of as much as 7 percent downtime, and recalls his own experiments with the Jujutsu (JJ) version control system.
The core of the walkthrough is the architecture of Anthropic’s system, called Scion. It uses append-only change sets that point to full file contents in blob storage, with no pack files, locking, or refs to move. Features like blame, path history, and commit graph skip lists are computed as derived data through a recursive mechanism that can be eager or deferred and changed without touching the client. Theo also discusses when it makes sense to build custom tooling instead of using vendored products.
📺 Source: Theo – t3․gg · Published October 16, 2026
🏷️ Format: News Analysis
