diff --git a/cmd/internal-tools/bundle-check/main_test.go b/cmd/internal-tools/bundle-check/main_test.go
index b963556..a69cceb 100644
--- a/cmd/internal-tools/bundle-check/main_test.go
+++ b/cmd/internal-tools/bundle-check/main_test.go
@@ -1,8 +1,10 @@
 package main
 
 import (
+	"bytes"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 )
 
@@ -55,3 +57,55 @@ func TestBundleSpec_ResolvesSpecAliases(t *testing.T) {
 		t.Errorf("unstable bundle hash: %s vs %s", result.SHA256, second.SHA256)
 	}
 }
+
+func testdataSpec(t *testing.T, name string) string {
+	t.Helper()
+	path, err := filepath.Abs(filepath.Join("testdata", name))
+	if err != nil {
+		t.Fatal(err)
+	}
+	return path
+}
+
+func TestCheck_RejectsSpecThatRegistersNoProperties(t *testing.T) {
+	var stdout bytes.Buffer
+	err := check(repoSpecSrc(t), testdataSpec(t, "no-properties.ts"), &stdout)
+	if err == nil {
+		t.Fatal("a spec registering zero properties passed the gate: a run against it reports no violations while checking nothing")
+	}
+	if !strings.Contains(err.Error(), "registers no properties") {
+		t.Errorf("failure must name the missing registration, got: %v", err)
+	}
+	if !strings.Contains(stdout.String(), "bundled: ") {
+		t.Errorf("bundle size and hash must still be reported for a spec awaiting its properties, got: %q", stdout.String())
+	}
+}
+
+func TestCheck_ReportsRegisteredPropertyCountAndNames(t *testing.T) {
+	var stdout bytes.Buffer
+	if err := check(repoSpecSrc(t), testdataSpec(t, "spec.ts"), &stdout); err != nil {
+		t.Fatalf("check: %v", err)
+	}
+	if !strings.Contains(stdout.String(), "properties registered: 1 (noUncaughtExceptions)") {
+		t.Errorf("expected the registered count and name, got: %q", stdout.String())
+	}
+}
+
+// TestCheck_ReportsUnchangedBundleHash pins the reported bundle of a fixture
+// that imports nothing, so the hash moves only when the bundler itself does.
+// Frozen pre-registrations record these hashes, so bundle-check reporting a
+// different bundle (the runtime-entry one, say) silently invalidates them.
+func TestCheck_ReportsUnchangedBundleHash(t *testing.T) {
+	const (
+		plainBytes  = 57
+		plainSHA256 = "bd757084b3f29c04c68ba2aa4c7b93e63b6dc6dd08ea3f726e0d1878be845888"
+	)
+	result, err := bundleSpec(repoSpecSrc(t), testdataSpec(t, "plain.ts"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(result.JavaScript) != plainBytes || result.SHA256 != plainSHA256 {
+		t.Errorf("reported bundle changed: %d bytes sha256=%s, want %d bytes sha256=%s",
+			len(result.JavaScript), result.SHA256, plainBytes, plainSHA256)
+	}
+}
diff --git a/cmd/internal-tools/bundle-check/testdata/no-properties.ts b/cmd/internal-tools/bundle-check/testdata/no-properties.ts
new file mode 100644
index 0000000..f9ce909
--- /dev/null
+++ b/cmd/internal-tools/bundle-check/testdata/no-properties.ts
@@ -0,0 +1,7 @@
+import { Tap, actions } from "@sanderling/spec";
+
+export const properties = {};
+export const actionsRoot = actions((state) => {
+  const button = state.ax.find("desc:primary");
+  return button ? [Tap({ on: button })] : [];
+});
diff --git a/cmd/internal-tools/bundle-check/testdata/plain.ts b/cmd/internal-tools/bundle-check/testdata/plain.ts
new file mode 100644
index 0000000..64a32fd
--- /dev/null
+++ b/cmd/internal-tools/bundle-check/testdata/plain.ts
@@ -0,0 +1 @@
+export const answer = 42;