Disclosure
Anthropic avoided building an IDE to target future AI model scaling
“If we want some product that has like very broad a product market fit today, we would build, you know, a cursor or a Windsurf or something like this. Like these are awesome products that so many people use every day. I use them. That's not the product that we …”
Assertion Supported
Cherny: Anthropic is currently bordering on AI Safety Level 3 capabilities
“Yeah, we're kind of bordering on three right now.”
Insight
Cherny: AI prototyping informs engineering decisions faster than writing design docs
“Before I would write a big design doc, and I would think about a problem for a long time before I would build it sometimes for some set of problems, and now I'll just ask quad code to prototype, like, three versions of it, And I'll try the feature and see whic…”
Prediction Not checkable as stated
Cherny: Foundation models will eventually subsume external memory and RAG architectures
“Everything is the model. Like that's the thing that wins in the end. And it just, as the model gets better, it's it subsumes everything else. So, you know, at some point the model will encode its own knowledge graph. It'll encode its own like KV story if you j…”
Opinion
Cherny: Claude Code delivers up to 10x productivity gains for Anthropic engineers
“Anecdotally for me, it's probably two X my productivity. So I'm just like, I'm an engineer that codes all day, every day. For me, it's probably two X. Yeah. I think there's some engineers at Anthropic where It's probably 10 X their productivity”
Prediction Not checkable as stated
Cherny: Prompt engineering skills for coding may become obsolete within 3 months
“But I also agree that, you know, maybe in a month or two months or three months, you won't need this anymore because, you know, the bitter lesson always wins.”
Assertion Not checkable as stated
Cherny: Some Anthropic engineers rack up thousands daily running Claude Code automations
“And there's some people at Anthropic that have been racking up like thousands of dollars a day with this kind of automation.”
Assertion Not checkable as stated
Anthropic estimates Claude wrote 80% to 90% of the Claude Code codebase
“Probably near 80, I'd say.”
Assertion Not checkable as stated
Cherny: Claude Code is the thinnest possible wrapper over the underlying model
“All the secret sauce, it's all in the model and this is the thinnest possible wrapper over the model. We literally could not build anything more minimal. This is the most minimal thing.”
Assertion Not checkable as stated
Anthropic uses Claude to rewrite Claude Code from scratch every 4 weeks
“We've rewritten it from scratch, yeah, probably every three weeks, four weeks or something, and it just like all the, it's like a ship of Theseus, right? Like every piece keeps getting swapped out, and just because quad is so good at writing its own code.”
Assertion Not checkable as stated
Cherny: Internal DAU for Claude Code went vertical across Anthropic
“Then we gave all the engineers and researchers at Anthropic access and pretty soon everyone was using it every day. And I remember we had this DAU chart for internal users and I was just watching it and it was vertical like for days”
Insight
Cherny: Highly capable models make simple scaffolding sufficient
“And it's funny with, when the model is so good, the simple thing usually works. You don't have to over-engineer it.”
Insight
Cherny: Claude Code is built as a composable Unix utility like grep
“We think of it as like a Unix utility. Right. So it's like the same way that you would compose, you know, grep or cat or oh, cat. Or something like this. The same way you can compose code into workflows.”
Assertion Not checkable as stated
Anthropic runs Claude Code in CI/CD to semantically lint GitHub pull requests
“For quad code internally in the GitHub repo, we have this GitHub action that runs. And the GitHub action invokes quad code with a local slash command. And the slash command is lint. So it just runs a linter using quad. And it's a bunch of things that are prett…”
Insight
Cherny: Rich CLI development resembles cross-browser issues of the IE6 era
“So building in this way, it feels to me a little bit like a building for the browser back in the day where you had to think about like,
Internet Explorer six versus Oprah versus like Firefox and whatever.
Like you have to think about these cross-terminal diffe…”
Insight
Cherny: Coding agents require early failure detection over delayed intervention
“And what we find is that if the model is doing something wrong, it's better to identify that earlier and correct it earlier, and then you're gonna have a better time. If you wait for the model to just go down this like totally wrong path and then correct it 10…”
Disclosure
Anthropic tests Claude for internal code reviews, not yet releasing it
“We have some experiments where Quad is doing code review internally. We're not super happy with the results yet, so it's not something that we want to open up quite yet.”
Disclosure
Cherny: I have not manually written a unit test in months
“So for example, like, I have not manually written a unit test in many months.”
Assertion Not checkable as stated
Anthropic engineer built a Slack bot using Claude Code to automate PRs
“There was a really early version of Cloud Code many, many months ago, and this one engineer at Anthropic, Jeremy, built a bot that looked through a particular feedback channel on Slack, and he hooked it up to code to have code automatically put up PRs. With ju…”
Insight
Cherny: Agentic search trades tokens and latency for better security and accuracy
“So essentially at the cost of latency and tokens, you now have really awesome search. Without security downsides.”
Assertion Supported
Cherny: Claude Code uses pure chain-of-thought, not Think Tool
“Yeah, this is, it is, it's all chain of thought, actually, in quad code. So we don't use the think tool. Anytime that quad code does thinking, it's all a chain of thought.”
Insight
Cherny: Mandating Docker sandboxing for AI coding creates too much developer friction
“Ideally, the thing that we want is to always run code in a Docker container, and then it has freedom and you can kind of snapshot, you know, with other kind of tools later on top, you can snapshot, rewind, do all this stuff. Unfortunately, working with a Docke…”
Assertion Not checkable as stated
Claude Code's markdown parser was generated by Claude in two prompts
“And so the night before the release at like, 10 PM, I'm like, all right, I'm going to do this. So I just asked Quad to write a markdown parser for me. And they wrote it.
It wasn't quite zero shot, but after, you know, like maybe like one or two prompts, it got…”
Prediction Not checkable as stated
Boris Cherny: Developers will increasingly generate custom libraries using AI
“I expect that a lot more people are going to start doing things like this, like writing your own libraries or just shipping every feature.”
Boris Cherny