The version that was live on GitHub the day they published their blog post was missing compilation instructions, didn't cleanly compile and didn't pass GitHub Actions CI.

The project itself did compile most of the time it was being developed - the coding agents had been compiling it the whole time they were running on it.

Shortly after the blog post they updated the GitHub repo with compilation instructions and it worked. I took this screenshot with it: https://static.simonwillison.net/static/2026/cursor-simonwil...

The "it didn't even compile" criticism is valid in pointing out that they messed up the initial release, but if you think "it never compiled" you have an incorrect mental model.

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orwin 5 hours ago | parent [-]

Also, didn't it use Servo crates? I don't think you can say 'from scratch' if 60% of the actual work is from an external lib.

If I install an Arch Linux, I don't say I 'installed Linux from scratch'.

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simonw 5 hours ago | parent [-]

It used cssparser and html5ever from the Servo project, and it used the Taffy library for flexbox and CSS grid layout algorithms which isn't officially part of Servo but is used by Servo.

I'd estimate that's a lot less than 60% of the "actual work" though.

	▲	orwin 5 hours ago \| parent [-]
		My bad, I was misinformed, thanks for correcting me, I thought it used the renderer, not just the parser. Thats honestly way better than what I thought.