Interesting! I'll probably start doing that. I hadn't connected the satisfies keyword to this problem, but it seems like a good solution.
My complaint about writing the schemas twice isn't the busywork (which is, like, annoying, but whatever I'll live). But the concern about small discrepancies between the two causing problems later.
I'll definitely use this going forward.
interface Person { firstName: string; lastName: string; }
const PersonSchema = z.object({ firstName: z.string(), lastName: z.string(), }) satisfies z.Schema<Person>;