diff --git a/delivery/ci/publish_mcp_artifacts.py b/delivery/ci/publish_mcp_artifacts.py
index 4a82eaf..e2694f6 100644
--- a/delivery/ci/publish_mcp_artifacts.py
+++ b/delivery/ci/publish_mcp_artifacts.py
@@ -803,6 +803,9 @@ def registry_tags():
         return []
     require(status == 200, "registry_tags_unavailable")
     value = strict_json(raw)
+    # GHCR returns null while the repository contains only untagged digests.
+    if "tags" in value and value["tags"] is None:
+        value["tags"] = []
     require(value.get("name") == IMAGE.removeprefix("ghcr.io/") and isinstance(value.get("tags"), list)
             and len(value["tags"]) < 1000 and all(isinstance(tag, str) for tag in value["tags"]), "registry_tags_window")
     return value["tags"]
diff --git a/tests/test_mcp_publication.py b/tests/test_mcp_publication.py
index d78d606..a14fc68 100644
--- a/tests/test_mcp_publication.py
+++ b/tests/test_mcp_publication.py
@@ -730,6 +730,16 @@ class TransportBoundaryTests(unittest.TestCase):
     def setUp(self):
         self.p = importlib.import_module("delivery.ci.publish_mcp_artifacts")
 
+    def test_registry_without_tagged_images_has_no_reusable_runtime(self):
+        with patch.object(self.p, "registry_request", return_value=(200, b'{"name":"zeegin/v8std-mcp","tags":null}')):
+            self.assertEqual(self.p.registry_tags(), [])
+        for value in ({"name": "zeegin/v8std-mcp"},
+                      {"name": "other/repository", "tags": None},
+                      {"name": "zeegin/v8std-mcp", "tags": "stable"}):
+            with self.subTest(value=value), patch.object(self.p, "registry_request", return_value=(200, json.dumps(value).encode())):
+                with self.assertRaisesRegex(self.p.PublicationError, "registry_tags_window"):
+                    self.p.registry_tags()
+
     def test_real_local_smoke_validates_inspect_array_for_both_platforms_and_cleans_failures(self):
         good = {"Config": {"User": "10001:10001", "Labels": {"org.opencontainers.image.revision": "d" * 40}},
                 "HostConfig": {"Privileged": False, "ReadonlyRootfs": True}}