Anthropic builds Scion, a git replacement, as Claude pushes merges to 30K per day
The AI company replaced git with custom version control as autonomous code generation created a 12x surge in daily merges.
Part of a larger narrative
Anthropic's Claude Evolution
- Anthropic builds Scion, a git replacement, as Claude pushes merges to 30K per dayyou are here
- Anthropic warns small AI models may self-replicate across smart-home devices within months
- Anthropic discloses Claude AI sent a fake murder tip to Philadelphia police
- Anthropic cuts Claude reasoning-token theft by up to 99%, flags Chinese rivals
- Anthropic launches Claude Haiku 5.5, cuts small-model API prices ~75%
What to know
- Anthropic's autonomous code generation scaled merge volume 12-fold in four months (2.5K to 30K+ daily), breaking git's design assumptions and forcing a ground-up rewrite of version control infrastructure.
- Claude itself built Scion's most critical component—rewriting the ingestion pipeline with 20x better memory efficiency and 4x speed with minimal prompting—turning the AI bottleneck into the solution.
- Anthropic frames this as a preview: other heavy users of AI coding tools will soon face identical infrastructure strain, suggesting a wave of custom VCS implementations across the industry.
- The post raises a philosophical question about human agency in software development: with agents autonomously generating and merging tens of thousands of changes daily, what remains for human engineers to do?
The dispute Whether Anthropic's 30K+ daily merges represent genuine software engineering progress solving real problems, or a tautological loop where removing bottlenecks merely increases code churn without output. · positions read across 51 posts and comments
AI's capability to scale code generation and self-optimize infrastructure is profound and represents a genuine inflection point in development practice.
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“I feel like the advantage of having these models in house can't be understated. Companies with access to inferior models, tr…”
trnvll · Hacker News ↗
The claimed infinite merge demand and code velocity don't align with solving real-world problems; something about this scale is philosophically incoherent.
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“If the goal is to write software which solves real problems, how can the demand for code grow infinitely?”
netburst · Hacker News ↗
Other companies will rush to build similar systems and suffer the maintenance burden, not realizing they lack Anthropic's scale or internal AI models.
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“There's going to be an ugly phase where everybody FOMOs into thinking they need to do the same, only to realize that they're not Anthropic/Google/etc.”
preommr · Hacker News ↗
How it unfolded 1 development · click the chart to see its coverage articlespostscomments
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Anthropic publishes technical details of Scion architecture
Anthropic released a blog post describing Scion's design and why git—which stores 100 GB of history and 25 GB of compressed code in their monorepo—became impractical. The post notes Claude rewrote the ingestion pipeline to be 20x more memory-efficient and 4x faster with no further instruction.
“Claude's ability to write code was both what put us in this situation in the first place and how we were able to quickly build a high-quality, scalable system to deal with it.”
— Anthropic -
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Anthropic, of course, is not just riding down the vibe bobsled, they have rocket packs attached to the bobsled, careening at record speed https://www. anthropic.com/engineering/rede signing-source-control
2 more of the top 3 · 51 posts in this stretch
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Many parts of the Git distributed version control are the results of good decision made. Anthropic source control team just think that their trade-offs needs are vastly different from other businesses. They said these too:1. they have no-cap token spend allowance internally2. their agent swarms are amongst the largest if not the largest, again…
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“In May 2026, Anthropic averaged around 2,500 code changes merged per day; as of September, we merged over 30,000 per day.” 12x growth in just 4 months. This explains why GitHub keeps breaking.
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background
Anthropic completes migration to Scion — In five months, a team of seven engineers with Claude's assistance completed a full migration of Anthropic's monorepo from git to Scion, also shipping a code review system (Antique), code search, and IAM tooling.
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background
Merge rate surges to over 30,000 per day — By September 2026, Anthropic's daily merge count grew to over 30,000—a more than tenfold increase since May—as Claude autonomously iterates on research loops and builds services at scale.
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background
Anthropic begins building Scion replacement for git — Facing exponential growth in merges, Anthropic starts building an in-house version control system called Scion, designed for centralized, high-throughput operation.
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background
Anthropic's merge rate hits 2,500 per day — By May 2026, Anthropic's monorepo averaged around 2,500 code changes merged per day, already straining git's design.
Also covered reported alongside — the timeline has no entry for these yet
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5 outlets Redesigning source control at Anthropic (via) Interesting piece from Anthropic describing …
first by Simon Willison's Weblog, 7h ago · also The Register, Simon Willison, HN Best, HN Frontpage
2 more headlines
- Anthropic reinvents source control as Claude floods the world with code The Register · 3h ago
- Redesigning source control at Anthropic Simon Willison · 3h ago
and 1 smaller piece
What people are saying 21 voices from 2 sites · best of 51 · verbatim
- What problems are being solved by the 30,000+ daily code changes, and how does solving problems lead to infinite merge demand?
- Will other companies that build similar VCS systems face similar total-cost-of-ownership challenges, and do they have access to Claude-tier models to maintain the infrastructure?
- Today
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My favorite part about this is it's all about the bottlenecks.Anthropic says 12x daily merged changes, and its Git-based infrastructure started straining. I've seen that even locally git trying to keep up and having to shift how i commit in parallel.If agent workloads grow to 20x or 50x today's levels, I think we'll keep finding bottlenecks across…
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I have a theory (loosely held, it's just an idea, not a belief) that this could lead to something I call Evolutionary Architecture. That instead of waiting for vulnerabilities to be discovered in code, that systems could end up with code being changed and re-implemented by agents so fast that attacks aren't able to probe for attacks because they…
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At least they admit they're the reason Github is breaking. 30.000 LLM-sized commits to a single repo every day with agents hammering git blame as well, my god. I don't want to know what kind of useless onslaught the Github infrastructure has to withstand in total. https://www. anthropic.com/engineering/rede signing-source-control Of course they're…
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This is interesting from the perspective of scale (because Claude is pumping out massive volume of code). I am still lacking semantic re-invention of source control for agentic era. As others have pointed out - what is the point of human source control in the era where it's just agents building things. We may need to rethink this completely - in…
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Any startup that hires enough ex-Googlers ends up with an ad hoc, informally-specified, bug-ridden, slow implementation of half of Google infra https://www. anthropic.com/engineering/rede signing-source-control
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> As our monorepo grows, it increasingly doesn’t fit that design space. The history of our main branch alone is almost 100 GBThe first thing that hits me is, did you consider not going all in on a monorepo? I know it has been the trend in general, but it seems a bit of a red flag when you go from "let's have a monorepo it will make merging easier"…
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The Scion project seems like a great example of identifying and addressing scaling issues (just in time, it seems). Just 7 engineers! It makes me think I'd pay Anthropic $300K/year to work on such problems.But it's a sad example, for open-source and for small engineering companies. Instead of infrastructure being more easily shared with the…
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My first real job was at Oracle. At the time Oracle started to write their own source control system (and move off of clearcase, which was a very reasonable thing to do).The guy who ran that project called it his "$LASTNAME law" that every large company will at some point write their own source control system.I laughed.About a year later I went to…
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You’d expect that while the frontier of changes fans out and grows, some of them burn out and disappear and some of them survive and solidify into a relatively static code base.The big baddies of build have worked this way for a long time already. Git surfaces a single Merkle tree id for the whole repo on each commit, but build tools like…
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This article doesn't do a very good job of convincing me that git is technically incapable of handling the described workload. There are a lot of steps between vanilla git and building your own VCS from zero.If I was an investor I would be on the phone with Dario asking why we are wasting engineering talent on reinventing source control and…
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Anthropic now states that Claude can code better than its engineers but humans are still valuable primarily to tell Claude “no.” This was shared as part of their post about a small team building a replacement for git in five months. https://www. anthropic.com/engineering/rede signing-source-control
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> a competitor to Google searchFielding a web index takes a massive amount of compute and storage of a very different kind than what Anthropic is using. AI is extremely heavy on GPU, maybe somewhat on storage but (comparatively) light on CPU. They need CPU to train coding agents, obviously, but scaling to a billion user web search is a whole…
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I don't get one thing, if agents are so great at developing software at massive scale, why wouldn't Anthropic, instead of just selling tokens to other companies to use its agents, let those agents develop highly profitable services for Anthropic to support their IPO valuation or not require raising money at all? For example, a competitor to Google…
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This is interesting to me, as I was thinking of adding a Git server to my AI orchestrator when I eventually need to split agent containers off of the main machine (to make agent CPU horizontally scalable).Maybe I should just bite the bullet and use a different VCS system entirely once I get there, which has most of the Anthropic system's…
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Reading this post put me in a similar head space.I believe you're mostly thinking of version history though. There’s plenty of other reasons to have source control we still need, like guarding against racing writes or continuous integration to ensure correctness. Even some industries require version history for compliance reasons.I do love how AI…
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What is are the benefits of supporting extremely high churn rate in version control? What is the code doing? What problems are being solved? Are changing requirements the driving factor, and if so, why are requirement changes accelerating?> ..., the latent demand for merging code is practically infinite, and every bottleneck we remove immediately…
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Agents use source control, too. It's a pretty important part of the development process to understand how code has changed.For example, you can imagine, at the extreme, that agents could get caught in code change loops: a code change seems appropriate, it is implemented, it turns out there's some external factor which makes it not appropriate, the…
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Excuse me for throwing up this stupid idea, but if code changes per unit of time keep growing at this rate and are not slowing down with infinite merging demand, it seems that this repo will be in a constant state of continuous change and we constantly roll forward with automated code and obviously no direct human supervision, then why even have…
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Not to downplay Anthropic's engineering work here, but I suspect we'll see a lot more reinvention of the wheel, even at smaller startups, as AI makes writing code significantly cheaper.The tradeoff between building something custom and adapting an existing solution is changing. Whether maintaining all that custom software turns out to be equally…
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Every now and then I like to browse the claude code release notes just to get a sense of the number of changes in that product over time. There's little choice but to simply count bullet points if you want to try to quantify it, but it's interesting how that count over time compares with the charts in this article:
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> Earlier in the year, we had largely handwritten the first version of the git-to-Scion ingestion pipeline as a prototype. We thought it was good—until we got our hands on an early internal snapshot of Claude Mythos Preview. We asked it to rewrite the whole thing, and with no further instructions, it produced a version that consumed 20x less…