According to Michael Truell on Twitter, a team used GPT-5.2-powered agents in Cursor to autonomously write over 3 million lines of code across thousands of files within just one week. The agents built an entire browser from scratch, including a Rust-based rendering engine, HTML parsing, CSS cascade, layout, text shaping, painting, and a custom JavaScript VM. While the resulting product is not yet at the level of Webkit or Chromium, the successful rendering of simple websites demonstrates significant progress in AI-driven software engineering. This achievement signals a major shift in how businesses can approach large-scale coding tasks, software prototyping, and rapid product iteration, leveraging AI to accelerate innovation and reduce development costs (source: Michael Truell, Twitter: https://x.com/mntruell/status/2011562190286045552).