Why Anthropic Had to Build Scion (And You Might Too)!

Anthropic Scion is the in-house source control system Anthropic built after git stopped keeping up with Claude: 30,401 code changes merged into one monorepo on September 9, against about 2,500 a day in May. A team of seven built Scion and moved the monorepo off git in five months, with Claude writing much of the code. ---- Higgsfield AI — Create AI Videos & Visuals Get 10% OFF here: https://higgsfield.ai?fpr=thomas-dccf7e 🚀 DYNAMOUS AI COMMUNITY Want to learn agentic coding with live daily events and workshops? Check out Dynamous AI: https://dynamous.ai/?code=646a60 Get 10% off here 👉 https://shorturl.smartcode.diy/dynamous_ai_10_percent_discount ⚡ HOSTINGER — RELIABLE HOSTING FOR YOUR PROJECTS (10% OFF) Whether you're shipping a portfolio, a side project, n8n flows, or AI agents — I use Hostinger for fast, affordable VPS + web hosting. Get 10% off here 👉 https://hostinger.com/DIYSMARTCODE n8n: https://n8n.partnerlinks.io/diysmartcode (Affiliate links — costs you nothing, supports the channel.) ---- Chapters 0:00 Anthropic Scion: 30,401 Merges in One Day Broke Git 0:30 Git Monorepo at Scale: Nearly 100 GB of History, 600+ PB of Traffic a Day 0:52 Shallow Clones, Sparse Checkouts and Git Mirrors: The Standard Fixes 1:12 Why Git Is Decentralized, and Why AI Agents Are Always Online 1:40 How Scion Works: History, Blame and Merges Move to the Server 2:14 Scion Changesets vs Git Commits (Write-Ahead Log + Spanner) 2:49 Three Cache Tiers: 99% Hit Rate, 200x Smaller Than Git Mirrors 3:56 Scion Benchmarks: git status 3.9 s vs 19 ms, Worktree 7.1 min vs 5.1 s 4:33 Built With Claude Mythos Preview: 20x Less Memory, 4x Faster 5:11 Engineers Telling Claude No: Reviewing Intent, Not Every Line 5:51 Claude Superfans in Slack and a Merge Queue Without a Global Lock 6:28 Is Scion a Git Replacement? Anthropic Says No (Google Piper, Meta Sapling) 7:09 My Test: Blobless Sparse Clone of git/git, 19 s vs 9 s 7:46 Verdict: What to Change in Your Own Git Repo Today What you will see in this 8-minute breakdown: → Why Anthropic's merge rate jumped from about 2,500 a day to 30,401 in one day → The git scaling fixes Anthropic tried first, including several hundred git mirrors → How Scion moves history, blame, commits and merges to the server, with every query exposed as an API → Changesets, three cache tiers and the published median times for git status, worktrees and agent change requests → How Claude Mythos Preview rewrote the git-to-Scion history pipeline → Why Anthropic says Scion is not for general use, and the 6 to 12 month warning for git platforms → My own measurement on git 2.53: full clone vs git clone --filter=blob:none --sparse, and what git blame costs on a lean clone Anthropic Engineering — Redesigning source control for agent scale: https://www.anthropic.com/engineering/redesigning-source-control Git docs — partial clone (blobless clones): https://git-scm.com/docs/partial-clone Git docs — git sparse-checkout: https://git-scm.com/docs/git-sparse-checkout Meta Sapling source control: https://sapling-scm.com/ Test repo used in my measurement (git/git): https://github.com/git/git Will git adapt to agents, or will every big model lab end up building its own Scion? Pick a side below. #Anthropic #Scion #Git #Monorepo #SourceControl #Claude #ClaudeCode #ClaudeMythos #AIAgents #AgenticCoding #AICoding #GitAlternative #SparseCheckout #PartialClone #DevOps #DeveloperTools #SoftwareEngineering #CI #Spanner #Sapling #Piper #VersionControl