The bus node follows the grants part's sealed user list, and only the grants part reads the vault's hashes (ADR 0547 clauses 7, 9; issue 1945)

The grants part writes its list as an object of its own bucket, sealed to the bus node's key, and names it in
user-list.sealed; the node-engine of the node holding mesh-broker is granted that one key and an object by name, the
grants part its bucket (the controller's copy carries the same grants, byte for byte, golden regenerated there).
A state may name its readers (announce, NamedReaders): mesh-vault.bus-accounts is read by mesh-grants alone.

go/buscompose/writers.go

@@ -44,6 +44,9 @@ func createsDeclared(p Principal, pattern string) bool {
 		return true
 	}
 	name, ok := strings.CutPrefix(pattern, "$JS.API.STREAM.CREATE.")
+	if ok && p.Kind == KindModule && p.Module == GrantsModule && name == GrantsUserListObjectStream {
+		return true
+	}
 	return ok && p.Kind == KindModule && p.Module == GrantsModule && slices.Contains(p.CreatesStreams, name) &&
 		safeSubject.MatchString(name)
 }
@@ -249,7 +252,10 @@ var WritersTable = []WriterRow{
 		KeptIn: "the object bucket " + DeclarationFilesBucket + "-<node> of each node, an object removed a day after the " +
 			"node's latest declaration no longer names it",
 		Others:   "a node-engine reads an object of its own bucket by its name and may neither list the bucket nor write it",
-		Subjects: []string{"$O.*.>"}, Writes: isControllerOrTheHandPath},
+		Subjects: []string{"$O.*.>"}, Writes: func(p Principal, pattern string) bool {
+			return isControllerOrTheHandPath(p, pattern) || grantsOwnObjects(p, pattern)
+		},
+		Shared: "the grants part writes its own object bucket " + GrantsUserListObjects + ", the user list sealed to the bus node, and no other (novox/hq ADR 0547 clause 7)"},
 	{State: "the declared-config mirror", Writer: "controller (lease holder), from its store, only on a change",
 		KeptIn: "key-value " + DeclaredConfigBucket, Others: "read through `reads` as mesh-controller." + MirrorDeclaredConfig,
 		Subjects: kvOf(DeclaredConfigBucket), Writes: isController},