Anthropic

“In May 2026, Anthropic averaged around 2,500 code changes merged per day; as of September, we merged over 30,000 per day.”

AnthropicPublished by the organization itself (post), no named author

“As of May 2026, more than 80% of the code we merge into Anthropic’s codebase was authored by Claude.”

AnthropicPublished by the organization itself (post), no named author

“roughly corroborates the 67% increase in merged pull requests”

AnthropicPublished by the organization itself (paper), no named author

“Anthropic uses Claude to write software far more than almost any other company”

AnthropicPublished by the organization itself (post), no named author

“Very often, we found that the role of the engineers was to tell Claude “no.””

AnthropicPublished by the organization itself (post), no named author

“if you align the org chart too much to the individual projects, you're going to end up re-orging every two weeks, which would be a total nightmare. … And there is the concept of a bet lead or a directly responsible individual. But the interesting thing is that they don't manage usually any of the other people, which … breaks the … previous way in which a lot of these things were done. But I think it leads us to be really flexible when you say, OK, actually, this project is not going to work out. Let's disband and keep going, and it's not a big deal.”

Mike KriegerHead of Anthropic Labs · Leader

“We are definitely still bottlenecked on reviews, especially for things that are touching some architecture pieces. And it's actually more subtle than just being bottlenecked on review, … we can carve out time differently. It's … bottlenecked on human ability to even fully conceptualize what we're doing.”

Mike KriegerHead of Anthropic Labs · Leader

“I was like, OK, I need to port this whole thing from Python to TypeScript. Like, as a-- you know, if I put on my, like, 2010s engineering hat, or even my early 2020s, like, that's a dumb idea. … But I was like, I think this is doable now. And I basically created this dynamic workflow set up. And over the weekend, … port the whole thing, like, verify it, double check it, … and then came back Monday to complete a workflow that was a ported version of that thing.”

Mike KriegerHead of Anthropic Labs · Leader

“But especially in a labs-type group where our whole cadence is two-week reviews where every project goes up for, we call it persevere or pivot. So basically, every project is up for review, and either it's time to keep going, … or it's time to pivot it, or even shut down. And we shut down projects basically every single one of those cycles. And the more you do it, the less it's just like, oh, no, my project is shut down. I failed. It's like, no, that is definitely the intention of the lab team is to prototype quickly, try to ship internally, maybe get it to early access, and if it doesn't work, wind it down.”

Mike KriegerHead of Anthropic Labs · Leader

“actually talked to Claude about the code and say, all right, these are the questions that I would have. Can you go investigate it? So it is kind of … code review, but still human-driven, and for the really important ones. And for the ones that are cosmetic visual changes, it's much more like we'll fix forward if we need to fix forward.”

Mike KriegerHead of Anthropic Labs · Leader

“We have one of our Slack challenges, like Project Unship, which is like, what is in the product right now? … Like, we unshipped styles, I think, recently, … used by a small percentage of people … very, sort of, prescriptive in the way that it worked, and skills were a much better application, something like that.”

Mike KriegerHead of Anthropic Labs · Leader

“But most usage is actually much more delegating via tagging… And then more advanced version is really trying to think of it as a teammate that is actually … has memory and can be proactive. And that's just really changed how we operate internally. It's much more like this multiplayer async proactive way than it is most people off in their own CLIs.”

Mike KriegerHead of Anthropic Labs · Leader

“So one of the reasons we built … artifacts that we shipped a couple of weeks ago was partially for that, which is you would send somebody a PR, and then they'd be like, I don't know, man, this is like 2000 lines of code. It looks like code to me. And what we started doing instead is sharing much more like, here's a … artifact. Here's the explanation. Here's the intention of the change. Here's the trade-offs that were made.”

Mike KriegerHead of Anthropic Labs · Leader