Opinion: Autonomous agents may generate millions of lines of code, but shipping software is another matter

AI-integrated development environment (IDE) company Cursor recently implied it had built a working web browser almost entirely with its AI agents. I won’t say they lied, but CEO Michael Truell certainly tweeted: “We built a browser with GPT-5.2 in Cursor.”

He followed up with: “It’s 3M+ lines of code across thousands of files. The rendering engine is from-scratch in Rust with HTML parsing, CSS cascade, layout, text shaping, paint, and a custom JS VM.”

That sounds impressive, doesn’t it? He also added: “It kind of works,” which is not the most ringing endorsement…

Too bad it wasn’t true. If you actually looked at Cursor engineer Wilson Lin’s blog post about FastRender, the AI-created web browser, you won’t see much boasting about a working web browser. Instead, there’s a video of a web browser sort of working, and a much less positive note that “building a browser from scratch is extremely difficult.”

Developers quickly discovered the “browser” barely compiles, often does not run, and was heavily misrepresented in marketing.

…this week‑long autonomous browser experiment consumed in the order of 10-20 trillion tokens and would have cost several million dollars at then‑current list prices for frontier models.

  • MonkderVierte ( MonkderVierte@lemmy.zip ) 
    27·
    8 months ago

    The rendering engine is from-scratch in Rust

    That’s a lie. LLM don’t do “from scratch”.

    And Heise (german IT-newspaper) tested it too: crashes on X, a bit less on wayland, urlbar sometimes not working, scrolling neither, stuff like that. In short, it’s crap.

    • wischi ( wischi@programming.dev ) 
      3·
      8 months ago

      But to be fair nobody does anything from scratch. Most people were in school at least for a few years. If you code, you’ve probably read a lot of code and documentation, if you draw you probably saw a lot of drawings, if you play chess you probably studied a lot of different games.

      • entwine ( entwine@programming.dev ) 
        2·
        8 months ago

        This is a dumb take. You didn’t understand the assignment.

        “From scratch” in software engineering usually means it was written without a starting point, being based off an existing implementation. It doesn’t mean it was written by someone who indepdently discovered computer science and software engineering on their own.

        You’re trying to regurgitate a pro-AI argument you read somewhere that defends OpenAI and others’ use of open source software to train their commercial models without paying, following open source licensing requirements, or even providing acknowledgement of their source (typically called “copyright infringement” or “plagiarism” when-non-billionaires do it). The argument you are plagiarising here tries to conflate human learning with AI training, which is as stupid as me saying that downloading movies for free is legal because I’m “training” my brain on that content.

        If you like AI slop, that’s cool. Idgaf. But if you’re going to wade into the controversies and politics though, maybe think a little harder before making a fool of yourself? The people you’re trying to argue with likely haven’t had their brain and critical thinking skills turned to mush by using LLMs as much as you have.