And then you just use your favorite js framework with Astro and it will still be good. I use Astro with react and heroui a lot. Since the latter does not need any js for many components anymore you still get zero js builds unless you actually need interactivity.

I actually find that agents are not especially performant with the “use Astro plus whatever” approach.

They seem to struggle to reason about the boundary between the two.

I haven't found that. I use Astro + SolidJS and it seems to work very well.

I intentionally avoid hydration (which I've always found to be flaky) and hydration-based frameworks like SolidStart, so possibly that helps. Or maybe that's just my own bias!

Agreed. Go with solidstart (who just released a big V2 upgrade a few months back) if you want an extremely elegant solution to async, error handling and heavily concurrent behaviors.

Very easy to setup and way more readable than the equivalent React code.

Even for highly interactive projects, Astro is still my favorite build system. Just toss the SPA component into the single Astro file and you're done.