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

Opinion 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. Still, numerous news sources and social media chatterboxes ran with the news that AI built a web browser in a week.

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 ...