Ask HN: Why all the sudden people are writing browsers with AI?

Summary

Blame Simon Willison ;)“A common complaint today from AI coding skeptics is that LLMs are fine for toy projects but can’t be used for anything large and serious.I think within 3 years that will be comprehensively proven incorrect, to the point that it won’t even be controversial anymore.I picked a web browser here because so much of the work building a browser involves writing code that has to conform to an enormous and daunting selection of both formal tests and informal websites-in-the-wild.Coding agents are really good at tasks where you can define a concrete goal and then set them to work iterating in that direction.A web browser is the most ambitious project I can think of that leans into those capabilities.”https://simonwillison.net/2026/Jan/8/llm-predictions-for-202...“The browser and this project were co-developed and very symbiotic, only because the browser was a very useful objective for us to measure and iterate the progress of the harness. The goal was to iterate on and research the multi-agent harness—the browser was just the research example or objective.”https://simonwillison.net/2026/Jan/23/fastrender/