diff --git a/internal/bootstrap/control_test.go b/internal/bootstrap/control_test.go
index 7b84df3..ff2fed0 100644
--- a/internal/bootstrap/control_test.go
+++ b/internal/bootstrap/control_test.go
@@ -307,3 +307,21 @@ func TestABrokerSettingReadFromAFileIsDeliveredToo(t *testing.T) {
 		t.Fatal("a plain path variable was taken for a secret")
 	}
 }
+
+// Step 9 with nothing built is a caller's fault, and it stops rather than pretending to pivot.
+func TestTheControlPlaneCannotBeInstalledWithoutABuild(t *testing.T) {
+	runtime := &asked{answer: aMeshThatAgrees(map[string]string{})}
+	control := controlPlane{container: "temp-mesh-controller", run: runtime.run, timeout: time.Second}
+	rewritten, err := Rewrite(theRealBundle(t), held)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = InstallControlPlane(context.Background(), installing(t, t.TempDir()),
+		Deps{Run: runtime.run}, control, rewritten.Declaration, Built{}, pushedReference, func(string) {})
+	if err == nil || !strings.Contains(err.Error(), "was not built") {
+		t.Fatalf("a missing build was not refused: %v", err)
+	}
+	if runtime.ran("module add") {
+		t.Error("something was registered without a manifest")
+	}
+}