Lenny's Podcast: Product | Career | Growth
00:08:49 · Boris Cherny
And so, when I joined Ant, I spent one month hacking, and built a bunch of weird prototypes. Most of them didn't ship, and weren't even close to shipping. It was just understanding the boundaries of what the model can do. Then I spent a month doing post-training. So, to understand the research side of it. And I think, honestly, that's just, for me, as an engineer, I find that to do good work you really have to understand the layer under the layer at which you work. And with traditional engineering work, if you're working on product, you want to understand the infrastructure, the run time, the virtual machine, the language, whatever that is, the system that you're building on. But, yeah. If you work in AI, you just really have to understand the model to some degree to do good work. So, I took a little detour to do that, and then I came back and just started prototyping what eventually became Claude Code. In the very first version of it I have a ... There's, like, a video recording of this somewhere, because I recorded this demo, and I posted it. It was called Claude CLI back then. And I just showed off how it used a few tools, and the shocking thing for me was that I gave it a batch tool, and it just was able to use that to write code, to tell me what music I'm listening to when I asked it like, "What music am I listening to?" And this is the craziest thing. Right? Because it's, like, there's no ... I didn't instruct the model to say, "Use this tool for this," or do whatever. The model was given this tool, and it figured out how to use it to answer this question that I had that I wasn't even sure if it could answer, "What music am I listening to?" And so, I started prototyping this a little bit more. I made a post about it, and I announced it internally and it got two likes. That was the extent of the reaction at the time, because I think people internally ... When you think of coding tools, you think of IDEs, you think of all these pretty sophisticated environments. No one thought that this thing could be terminal-based. That's a weird way to design it, and that wasn't really the intention. But from the start I built it in a terminal, because for the first couple months it was just me. So, it was just the easiest way to build. And, for me, this was actually a pretty important product lesson. Right?
00:10:55 · Boris Cherny
This is, like, you want to under-resource things a little bit at the start. Then we started thinking about what other form factors we should build, and we actually decided to stick with the terminal for a while. And the biggest reason was the model is improving so quickly, we felt that there wasn't really another form factor that could keep up with it. And, honestly, this was just me struggling with, "What should we build?" For the last year, Claude Code has just been all I think about. And so, just late at night this is just something I was thinking about like, "Okay. The model is continuing to improve. What do we do? How can we possibly keep up?" And the terminal was, honestly, just the only idea that I had. And, yeah. It ended up catching on. After I released it, pretty quickly it became a hit at Anthropic, and the daily active users just went vertical, and it ... Really early on actually, before I launched it, Ben Mann nudged me to make a DAU chart. And I was like, "It's early. Should we really do it right now?" And he was like, "Yeah." And so, the chart just went vertical pretty immediately. And then in February, we released it externally. Actually, something that people don't really remember is Claude Code was not initially a hit when we released it. It got a bunch of users. There was a lot of early adopters that got it immediately, but it actually took many months for everyone to really understand what this thing is. Again, it's just so different. And when I think about it, part of the reason Claude Code works is this idea of latent demand where we bring the tool to where people are, and it makes the existing workflows a little bit easier. But also because it's in the terminal, it's a little surprising, it's a little alien in this way. So, you have to be open-minded, and you had to learn to use it. And, of course, now Claude Code is available in the iOS and Android Claude app. It's available in the desktop app. It's available on the website. It's available as IDE extensions in Slack and GitHub. All of these places where engineers are it's a little more familiar, but that wasn't the starting point. So, yeah. At the beginning it was a surprise that this thing was even useful.
00:12:55 · Boris Cherny, Lenny Rachitsky
And as the team grew, as the product grew, as it started to become more and more useful to people, just people around the world from small startups to the biggest [inaudible 00:13:05] companies started using it, and they started giving feedback. And I think just reflecting back it's been such a humbling experience, because we keep learning from our users and just the most exciting thing is none of us really know what we're doing, and we're just trying to figure out along with everyone else. And the single best signal for that is just feedback from users. So, that's just been the best. I've been surprised so many times. [00:13:29] S1: It's incredible how fast something can change in today's world. You launched this a year ago. And it wasn't the first time people could use AI to code, but in a year, the entire profession of software engineering has dramatically changed. Like, there's all these predictions, "Oh, AI is going to be written ... 100% of code is going to be written by AI." Everyone is like, "No. That's crazy. What are you talking about?" But now it's like, "Oh, of course. It's happening exactly as they said." So, things move so fast, and change so fast now.
00:13:58 · Boris Cherny
[00:13:58] S0: Yeah. It's really fast. Back at Code with Claude back in May, that was our first developer conference that we did as Anthropic, I did a short talk. And in the Q&A after the talk, people were asking, "What are your predictions for the end of the year?" And my prediction back in May of 2025 was, "By the end of the year, you might not need an IDE to code anymore. And we're going to start to see engineers not doing this." And I remember the room audibly gasped. It was such a crazy prediction. But I think at Anthropic, this is just the way ... The way we think about things is exponentials. And this is very deep in the DNA. Like, if you look at our co-founders, three of them were the first three authors on the scaling laws paper. So, we really just think in exponentials. And if you look at the exponential, the percent of code that was written by Claude at that point, if you just trace the line, it's pretty obvious we're going to cross 100% by the end of the year, even if it just does not match intuition at all. And so, all I did was trace the line. And, yeah. In November that happened for me personally. And that's been the case since. And we're starting to see that for a lot of different customers too.
00:15:01 · Lenny Rachitsky, Boris Cherny
[00:15:01] S1: I thought it was really interesting what you just shared there about the journey is this idea of just playing around and seeing what happens. This comes up with OpenClaw a lot, just, like, "Peter was playing around and a thing happened." And it feels like that's a central ingredient to a lot of the biggest innovations in AI is people just sitting around trying stuff, pushing the models further than most other people. [00:15:22] S0: That's the thing about innovation. Right? You can't force it. There's no road map for innovation. You just have to give people space. You have to give them ... Maybe the word is, like, safety. So, it's, like, psychological safety that it's okay to fail. It's okay if 80% of the ideas are bad. You also have to hold them accountable a bit. So, if the idea is bad, you cut your losses, move onto the next idea instead of investing more. In the early days of Claude Code, I had no idea that this thing would be useful at all, because even in February when we released it, it was writing maybe, like, I don't know, 20% of my code, not more. And even in May, it was writing maybe 30%. I was still using Cursor for most of my code. And it only crossed 100% in November. So, it took a while, but even from the earliest day, it just felt like I was onto something, and I was just spending every night, every weekend hacking on this. And, luckily, my wife was very supportive. But it just felt like it was onto something. It wasn't obvious what. And sometimes you find a thread, you just have to pull on it.
00:15:22 · Boris Cherny, Lenny Rachitsky
[00:15:22] S0: That's the thing about innovation. Right? You can't force it. There's no road map for innovation. You just have to give people space. You have to give them ... Maybe the word is, like, safety. So, it's, like, psychological safety that it's okay to fail. It's okay if 80% of the ideas are bad. You also have to hold them accountable a bit. So, if the idea is bad, you cut your losses, move onto the next idea instead of investing more. In the early days of Claude Code, I had no idea that this thing would be useful at all, because even in February when we released it, it was writing maybe, like, I don't know, 20% of my code, not more. And even in May, it was writing maybe 30%. I was still using Cursor for most of my code. And it only crossed 100% in November. So, it took a while, but even from the earliest day, it just felt like I was onto something, and I was just spending every night, every weekend hacking on this. And, luckily, my wife was very supportive. But it just felt like it was onto something. It wasn't obvious what. And sometimes you find a thread, you just have to pull on it. [00:16:17] S1: So, at this point, 100% of your code is written by Claude Code. Is that the current state of your coding? [00:16:23] S0: Yeah. So, 100% of my code is written by Claude Code. I am a fairly prolific coder. And this has been the case even when I worked back at Instagram. I was one of the top few most productive engineers. And that's still the case here at Anthropic. [00:16:38] S1: Wow. Even as head of the team?