Simon Willison

It's just, it's really hard to build, which is why few companies other than Salesforce have built something with that pattern that's that successful.

I've got a new 301.

Yeah, I am.

I think somebody will have built a full web browser, mostly using AI assistance, and it won't even be surprising.

Yes.

So we will have... Notoriously complicated.

Rolling a new web browser is one of the most complicated software projects I can imagine.

Yeah.

And specifically, the reason I think that's going to work is it turns out one of the most effective ways of using a coding agent is to give it an existing test suite and tell it, write code that passes these tests.

And in the past three weeks, I've done that for an HTML5 parser library.

I span up a brand new implementation of HTML5 parser that passed the 9,200 HTML5 conformance tests.

And I did it for a JavaScript interpreter.

Like I've written a naughty little Python JavaScript interpreter that passes the micro quick JS test suite.

And it wasn't very hard because once it's got a test suite, it just keeps on plugging it into all the test parses.

I think the browser specs are nearly at a point where a lot of these things, there are conformance suites, right?

There's the CSS conformance suites, there's all of this stuff.

Honestly, today, you could start one of these coding agents working on this problem, and it would make a surprisingly decent amount of progress.

Three years' time, I think it's going to be easy.

I think they'll be able to do it.

But the cheat code is the conformance suite.