Koru Standard Library: Refine — value-level constraints on declared fields `std/refine(Name) { name: type & constraint… }` — a definition surface for constraints on ABSTRACTS: it never touches a value, only meets bounds onto a declaration another module made. The `&`-atoms meet per field name, order-independently; a meet that lands empty is a loud KORU205 refusal, never a last-wins override. SURFACE: std/refine(Server) { port: i64 & >1024 & <=65535 } meets the `std/proto(Server)` declaration — refined fields must exist there on one agreed base. The meet is name-keyed, total, confluent: `std/refine` blocks in any module fold onto one facet that lands as a typed `Item.facet_decl` — consumers match the node, never comment text. LAYERING — the point of a separate module: a bound can arrive apart from the declaration. A library declares `std/proto(Server)` plainly; a downstream module writes `std/refine(lib/home:Server) { port: i64 & >1024 }` — `home:Name` rides the named-arg channel (proto's own `app/alpha:Health` convention), addressing the type by home while the facet meets the declaration program-wide. Definition is import-scoped; the constraint rides the type, so enforcement is type-global. ENFORCEMENT IS THE CONSUMER'S: refine emits data, never a check. `std/store` insert, `std/json` decode, `std/list:push` — each reads the facet at its own boundary and decides. An unconsumed facet is enumerable documentation, not a hole. v0 ATOMS: `>N` `>=N` `<N` `<=N` `==N` over integer literals, plus the `clamp(lo, hi)` normalizer — on integer scalar bases, raw (`i64`) or named through a terminal (`Port`). Disjunction (`*a | b`) is next. NOTE: `.k` files carry no host lines, so host types are spelled through `std/compiler:` aliases (Program, Item, Source, Allocator); the transform's own proc takes `std` inside its body and uses `koru_allocator()` — the canonical accessor emitted into every module (emitter_helpers.zig), riding the Debug leak counter. The explainer (`koruc <file> explain`) reports the met facet; the impl is refine.explain.kz. @retain: the generated gather invokes it.