The descriptor survived, const did not — full-stack Rust

One skeleton, many screens argued that admin screens should be declared as typed data rather than coded, and it ended by claiming the idea was independent of the stack: draw the boundary as a one-way dependency — domains depend inward on a framework that knows nothing about them — and validate it with a zero-diff refactor of a screen you already trust. That was React and TypeScript. This is the same claim re-run in Rust, where a descriptor can be a compile-time constant and a template is a macro. Because the first result is already published, the second stack is a replication with a control rather than a fresh opinion — which is rare enough to be worth doing properly. Companion to Topcoat and the shrinking cost of full-stack Rust . That post was written from the announcement and promised a follow-up reporting where the rough edges actually show. This is it, from the pilot that followed: a small admin panel built on Topcoat 0.6.2 and Toasty 0.10.0, and the four questions that post committed to answering. The pilot is open source — a clean clone runs both screens and the test that decides the argument. That phrase, a compile-time constant , is where the title comes from, so it is worth saying now what it buys and why I wanted it. A TypeScript descriptor is an array of objects assembled when the module loads. A Rust one can be more than that: &'static , Copy , allocated never, fully checked before the program starts. Going in, that looked to me like the same idea in a stricter form — if declaring a screen as data is good, then declaring it as data the compiler can see through and verify must be better still. I treated that property as the thing worth protecting, and the pilot was partly a test of whether it could be. The stack is deliberately a young one. Topcoat is six weeks old: Tokio's team announced it on 22 July 2026, the pilot pins 0.6.2, and the project still expects breaking changes. It is not the only full-stack Rust framework — Leptos and Dioxus have been at