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/nats.go

@@ -213,6 +213,9 @@ type Principal struct {
 	// StatesItsKeyToTheVault is a machine principal whose node-engine may ask the vault's `node-key` in its own name
 	// (issue 786, novox/hq ADR 0372): set while the vault's holder serves it. That one verb, and nothing else new.
 	StatesItsKeyToTheVault bool
+	// FollowsGrantsUserList is the machine principal of the node holding mesh-broker: its node-engine reads the grants
+	// part's sealed user list, one key and an object by name (novox/hq ADR 0547 clause 7, GrantsUserListFollows).
+	FollowsGrantsUserList bool
 	// BoundBuckets are the providers' buckets of entries, `<module>_bound`, a provisioner client reads its own
 	// machine's keys of (mesh-sdk go/provider, issue 679): every bucket named bound of a module the mesh places.
 	BoundBuckets []string
@@ -912,6 +915,11 @@ func PermissionsFor(p Principal) (Permissions, error) {
 		if p.StatesItsKeyToTheVault {
 			pub = append(pub, "mesh.seat."+VaultNodeKey.Seat+"."+CallKind+"."+VaultNodeKey.Verb+"."+CallerToken(p.Username()))
 		}
+		// And, on the node holding mesh-broker, the grants part's sealed user list it follows from take-over (novox/hq ADR
+		// 0547 clause 7): one key, and an object by its name.
+		if p.FollowsGrantsUserList {
+			pub = append(pub, GrantsUserListFollows()...)
+		}
 
 	case KindModule:
 		// 0. The watchman alone hears who connects and disconnects, and asks who is connected (ADR 0431 §2).
@@ -927,6 +935,8 @@ func PermissionsFor(p Principal) (Permissions, error) {
 			// And creating each stream a manifest declares, by its own name (the operator, 2026-10-26 08:54; issue
 			// 1790): the create and the read of that one stream, never an update, a delete or a stream not declared.
 			pub = append(pub, CreateStreamGrants(p.CreatesStreams)...)
+			// And its own object bucket, where it writes the user list sealed to the bus node (ADR 0547 clause 7).
+			pub = append(pub, GrantsUserListWrites()...)
 		}
 		// The view alone reads the build seats' workers for the backlog of asks (issue 1887 A8a).
 		if p.Module == ViewModule {