# The terminal was the only interface that could keep pace

Markdown copy of https://realalpha.app/s/the-terminal-was-the-only-interface-that-could-keep-pace/ on Real Alpha, the best minutes from long interviews with the people building AI. Cite and link the page, not this copy.

- Speaker: [Boris Cherny](https://realalpha.app/builders/boris-cherny/) · Boris Cherny is creator and head of Claude Code at Anthropic. · Created Claude Code at Anthropic and leads its team; previously spent about five years at Meta.
- Host: [Lenny Rachitsky](https://realalpha.app/people/lenny-rachitsky/) · Host, Lenny's Podcast · Spent seven years at Airbnb; his product newsletter has over 1M subscribers.
- Show: Lenny's Podcast
- Episode: [Head of Claude Code: What happens after coding is solved | Boris Cherny](https://realalpha.app/v/We7BZVKbCVw/), Feb 19, 2026
- Moment: 8:41 to 13:36 of the episode (5 min), playing on https://realalpha.app/s/the-terminal-was-the-only-interface-that-could-keep-pace/; the episode from there: https://realalpha.app/v/We7BZVKbCVw/?t=521

## Quote

> “And for me, this is actually a pretty important product lesson. It's like you want to **under-resource things** a little bit at the start.”
> — [Boris Cherny](https://realalpha.app/builders/boris-cherny/) at [10:44](https://realalpha.app/v/We7BZVKbCVw/?t=644) · Lenny's Podcast

## Takeaways

1. He prototyped alone in a terminal because it was fastest to build.
2. The terminal could keep pace as models improved quickly.
3. Claude Code took months to click with users after launch.

## About this segment

Boris Cherny built Claude Code in a terminal because it was the quickest prototype, then kept it there as models improved. The internal announcement got two likes, and it took months for users to understand the product.

From “Head of Claude Code: What happens after coding is solved | Boris Cherny”, Feb 19, 2026. [Watch the full episode](https://realalpha.app/v/We7BZVKbCVw/)

## Transcript

Transcribed by machine (Whisper) from the episode’s audio, so a word may be off here and there.

[8:47](https://realalpha.app/v/We7BZVKbCVw/?t=527) And so when I joined Ant, I spent one month kind of hacking and, you know, built a bunch of like weird prototypes. Most of them didn't ship and, you know, weren't even close to shipping. It was just kind of understanding the boundaries of what the model can do. Then I spent a month doing post-training. So to understand kind of 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.

[9:13](https://realalpha.app/v/We7BZVKbCVw/?t=553) And with traditional engineering work, you know, if you're working on product, you want understand the infrastructure, the runtime, the virtual machine, the language, kind of whatever that is, the system that you're building on. But yeah, if you're working 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 QuadCode. And the very first version of it, I have like a, there's like a video recording of the summer, because I recorded this demo and I posted it. It was called Quad CLI back then. And I just kind of showed off how it used a few tools. And the shocking thing for me was that I gave it a bash tool and it just was able to use that to write code to tell me what music I'm listening to. And I asked it, like, what music

[9:57](https://realalpha.app/v/We7BZVKbCVw/?t=597) 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, you know, use, you know, this tool for this or kind of 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 sense of the reaction at the time. Because I think people internally, when you think of coding tools, you think of IDEs, you think about all these pretty sophisticated environments. No one thought that this thing could be terminal-based.

[10:39](https://realalpha.app/v/We7BZVKbCVw/?t=639) That's sort of 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 is actually a pretty important product lesson. It's 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 kind of like struggling with kind of like, what should we build? You know, like for the last year, quad code has just been all I think about. And so just like late at night,

[11:22](https://realalpha.app/v/We7BZVKbCVw/?t=682) 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 really early on, actually, before I launched it, Ben Mann nudged me to make a DAU chart. And I was like, you know, it's kind of early, maybe, you know, should we really do it right now? And he was like, yeah.

[11:51](https://realalpha.app/v/We7BZVKbCVw/?t=711) 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 quad 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. Just again, it's like, it's just so different. And when I think about it, kind of part of the reason quad code works is this idea of latent demand, where we bring the tool to where people are and it makes existing workflows a little bit easier. But also because it's in a terminal, it's like a little surprising. It's a little alien in this way. So you have to kind of be open-minded and you have to learn to use it. And of course now, you know, QuadCode is available,

[12:35](https://realalpha.app/v/We7BZVKbCVw/?t=755) you know, in the iOS and Android Quad app. It's available in the desktop app. It's available on the website. It's available as IDE extensions and Slack and GitHub. You know, all of these places where engineers are, it's a little more familiar, but that wasn't the starting point. So yeah, I mean, at the beginning, it was kind of a surprise that this thing was even useful. And, you know, 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, you know, small startups to the biggest thing companies started using it and they started giving feedback. And I think just reflecting back, it's been such a humbling experience because we just, we keep learning from our users. And just the most exciting thing is like, you know, none of us really know what we're doing. And we're just trying to figure out along

[13:21](https://realalpha.app/v/We7BZVKbCVw/?t=801) 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. It's incredible how fast something can