> Why would they think it's a great idea to claim they implemented CSS and JS from scratch when the first thing any programmer would do is to look at the code and immediately find out that they're just using libraries for all of that?!

Programmers were not the target audience for this announcement. I don’t 100% know who was, but you can kind of guess that it was a mix of: VC types for funding, other CEOs for clout, AI influencers to hype Cursor.

Over-hyping a broken demo for funding is a tale as old as time.

That there’s a bit of a fuck-you to us pleb programmers is probably a bonus.

I mean... Cursor is the CEO's first non-internship job. And it was a VSCode Extension that caught fire atop the largest technological groundswell in a few decades.

The default assumption should be that this is a moderately bright, very inexperienced person who has been put way out over his skis.

I don't think he intentionally lied. He just didn't know how to check that and AI wrote

   - [tick mark emoji] implemented CSS and JS rendering from scratch - **no dependencies**.

I'm actually impressed by their ignorance. I could never sleep at night knowing my product is built on such brazen lies.

Bullshitting and fleecing investors is a skill that needs to be nurtured and perfected over the years.

I wonder how long this can go on.

Who is the dumb money here? Are VCs fleecing "stupid" pension funds until they go under?

Or is it symptom of a larger grifting economy in the US where even the president sells vaporware, and people are just emulating him trying to get a piece of the cake?

That is because I've noticed the AI just edits the version management files (package.json, cargo.toml, etc) directly instead of using the build tool (npm add, cargo add), so it always hallucinates a random old version that's found in its training set. I explicitly have to tell the AI to use the build tool whenever I use AI.

It seemingly did but after I saw it define a VerticalAlign twice in different files[1][2][3] I concluded that it's probably not coherent enough to waste time on checking the correctness.

Would be interesting if someone who has managed to run it tries it on some actually complicated text layout edge cases (like RTL breaking that splits a ligature necessitating re-shaping, also add some right-padding in there to spice things up).

[1] https://github.com/wilsonzlin/fastrender/blob/main/src/layou...

[2] https://github.com/wilsonzlin/fastrender/blob/main/src/layou...

[3] Neither being the right place for defining a struct that should go into computed style imo.

It's using layout code from my library (Taffy) for Flexbox and CSS Grid. Servo uses Taffy for CSS Grid, and another open source engine that I work on (Blitz) uses it for Flexbox, CSS Grid, Block and float layout.

The older block/inline layout modes seem to be custom code that looks to me similar but not exactly the same as Servo code. But I haven't compared this closely.

I would note that the AI does not seem to have matched either Servo or Blitz in terms of layout: both can layout Google.com better than the posted screenshot.

Cursor didn't write anything, they used ChatGPT 5.2.

It looks like there are two JS backends: quickjs and vm-js (vendor/ecma-rs/vm-js), based on a brief skim of the code. There is some logic to select between the two. I have no idea if either or both of them work.

I thought they'd plagiarise, not import. Importing servo's code would make it obvious because it's so easy to look at their dependencies file. And yet ... they did. I really think they thought no one would check?

You know, a good test would be to tell it to write a browser using a custom programming language, or at least some language for which there are no web browsers written.

The whole point of Servo is its not impossible to use like Chromium.