Type: url
Original: https://simonwillison.net/2026/Jan/19/scaling-long-running-autonomous-coding/
Status: partial
Summary
A link-blog post by Simon Willison on Cursor’s experiment in running hundreds of concurrent autonomous coding agents, organised as planners, sub-planners, workers and a judge agent, to build a web browser from scratch. The resulting project, FastRender, was reported to exceed a million lines of code across 1,000 files after close to a week of agent work; after initial skepticism over failing CI and missing build instructions, Willison built it on macOS and found it rendered pages legibly, with visible glitches.