This AI agent wrote 3 million lines of code in 1 week, built web browser from scratch: Internet reacts

By now, you know that AI can write code. Big names like Google and Microsoft have been mandating a certain percentage of their code to be written via AI. But how much can AI tolerate? And more importantly, will a mass-centric code written by AI work? Cursor’s CEO tested the theory to the limits. In a demonstration of how far AI has advanced in software development, Cursor CEO Michael Truell announced that a team of hundreds of AI agents, powered by OpenAI’s GPT-5.2 Codex model, autonomously constructed a full web browser in under seven days — producing more than 3 million lines of code without any human intervention.