ADR 0097: an undeclared base is said, not yet refused

03-DESIGN/01-to-be/18-building-a-module.md

@@ -220,9 +220,11 @@ and nothing uploaded on a second copy.
 ([ADR 0097](../../02-DECISIONS/0097-a-vendor-image-is-a-declared-build-input.md)). A build's `on`
 entry is a module's artifact or an image published elsewhere, pinned by digest, read from one
 build argument; the image is copied into the mesh's registry before the build and the recipe is
-handed the copy. A recipe whose `FROM` or `COPY --from` names a registry image the manifest did not
-declare is refused before the build, naming it and the remedy. *How it is checked:* builder tests
-on a declared and an unpinned vendor image, and a recipe test on what counts as a fetch.
+handed the copy. A recipe whose `COPY --from` names a registry image the manifest did not declare
+is refused before the build, naming it and the remedy; an undeclared `FROM` is said, not yet
+refused, because the mesh's own images start from a public base and declare none. *How it is
+checked:* builder tests on a declared and an unpinned vendor image, and a recipe test on what
+counts as a copy and what as a base.
 
 ### What it puts on a machine