diff --git a/modules/mesh-delivery-indexer/judge/rules.go b/modules/mesh-delivery-indexer/judge/rules.go
index 1928421c..d4f603bf 100644
--- a/modules/mesh-delivery-indexer/judge/rules.go
+++ b/modules/mesh-delivery-indexer/judge/rules.go
@@ -5557,20 +5557,40 @@ func StateProblems(m catalogue.Manifest) []string {
 // which names no module (issue 774, the operator 2026-11-03).
 var streamsKeptUntilMoved = map[string][]string{
 	"brother":                    {"device-asks"},
-	"mesh-build-go":              {"toolchains-go"},
-	"mesh-build-node":            {"toolchains-node"},
 	"mesh-mail":                  {"mail", "mail-sends"},
 	"only-office":                {"convert-asks"},
 	"mesh-delivery-checker":      {"checks"},
 	"mesh-delivery-forge-bridge": {"forge"},
 }
 
-// PredefinedFormProblems refuses each stream a module declares that streamsKeptUntilMoved does not name for it.
+// seatStreamsKeptUntilMoved are the streams kept the same way by the seat their module claims, not by its name: a build
+// seat's holder keeps its toolchain reports (`toolchains-go`, `toolchains-node`) whichever module holds the seat, since no
+// part fixes a module's name (novox/hq ADR 0666 §5; design 47 *A module's registration*, "No part fixes a name").
+var seatStreamsKeptUntilMoved = map[string][]string{
+	"node-build-go":   {"toolchains-go"},
+	"node-build-node": {"toolchains-node"},
+}
+
+// keptUntilMoved is whether a stream of a manifest is one kept until its module moves it: by the module's name, or by a
+// seat it claims.
+func keptUntilMoved(m catalogue.Manifest, stream string) bool {
+	if slices.Contains(streamsKeptUntilMoved[m.Module], stream) {
+		return true
+	}
+	for _, c := range m.Claims {
+		if slices.Contains(seatStreamsKeptUntilMoved[c.Name], stream) {
+			return true
+		}
+	}
+	return false
+}
+
+// PredefinedFormProblems refuses each stream a module declares that is not kept until it moves (keptUntilMoved).
 func PredefinedFormProblems(m catalogue.Manifest) []string {
 	var out []string
 	for _, s := range m.Streams {
 		// A stream that keeps its history is one of the bus's predefined forms (novox/hq ADR 0592 §6).
-		if !s.KeepsHistory() && !slices.Contains(streamsKeptUntilMoved[m.Module], s.Name) {
+		if !s.KeepsHistory() && !keptUntilMoved(m, s.Name) {
 			out = append(out, fmt.Sprintf("%s keeps the stream %q, outside the bus's predefined forms: keep it as a state, "+
 				"a log or an object store, which the runtime reads for the module's tools and others read by `reads`", m.Module, s.Name))
 		}
diff --git a/modules/mesh-delivery-indexer/judge/rules_test.go b/modules/mesh-delivery-indexer/judge/rules_test.go
index 7d9da3e6..2ef9b609 100644
--- a/modules/mesh-delivery-indexer/judge/rules_test.go
+++ b/modules/mesh-delivery-indexer/judge/rules_test.go
@@ -5111,6 +5111,16 @@ func caseTwoModulesCannotDeclareOneStream(t *testing.T) {
 	if got := PredefinedFormProblems(catalogue.Manifest{Module: "mesh-mail", Streams: a.Streams}); len(got) != 0 {
 		t.Fatalf("a stream kept until it moves was refused: %v", got)
 	}
+	// A build seat's toolchain stream is kept by the seat its module claims, whatever the module's name (ADR 0666 §5): the
+	// holder of node-build-go keeps toolchains-go; a module of the old holder's name claiming no build seat does not.
+	toolchains := []catalogue.StreamDeclaration{{Name: "toolchains-go", Events: []string{"toolchain.**"}}}
+	if got := PredefinedFormProblems(catalogue.Manifest{Module: "a-go-builder", Streams: toolchains,
+		Claims: []catalogue.Claim{{Name: "node-build-go", Scope: catalogue.ScopeNode}}}); len(got) != 0 {
+		t.Fatalf("the build seat's holder's toolchain stream was refused: %v", got)
+	}
+	if got := PredefinedFormProblems(catalogue.Manifest{Module: "mesh-build-go", Streams: toolchains}); len(got) != 1 {
+		t.Fatalf("a toolchain stream of a module claiming no build seat was kept by its name: %v", got)
+	}
 }
 
 // A seat name meaning two protocols is the failure nobody could diagnose afterwards.