fix(cli): validate --tag before any control plane call

libs/cli/langgraph_cli/deploy.py

@@ -415,7 +415,7 @@ def normalize_image_tag(value: str) -> str:
     Tags may only contain [A-Za-z0-9_.-].  Defaults to "latest" when empty.
     """
     if not value:
-        value = "latest"
+        value = _DEFAULT_IMAGE_TAG
     if not re.fullmatch(r"[A-Za-z0-9_.-]+", value):
         raise click.UsageError(
             "Image tag may only contain characters A-Z, a-z, 0-9, '_', '-', '.'"
@@ -1123,7 +1123,7 @@ def _run_local_build(
         remote_image = str(
             ImageReference(
                 f"{normalized_registry}/{normalize_name(repo_seed)}",
-                normalize_image_tag(tag),
+                tag,
             )
         )
         registry_host = normalized_registry.split("/")[0]
@@ -1507,7 +1507,9 @@ def _select_source(
     )
     if not use_remote_build:
         return ManagedRegistrySource(
-            prebuilt_image=image, image_name=image_name, tag=tag or _DEFAULT_IMAGE_TAG
+            prebuilt_image=image,
+            image_name=image_name,
+            tag=normalize_image_tag(tag or _DEFAULT_IMAGE_TAG),
         )
     if remote_build_flag is None and local_build_error:
         em = _get_emitter()

libs/cli/tests/unit_tests/cli/test_deploy_command.py

@@ -642,3 +642,13 @@ def test_push_to_with_deployment_id_fetches_the_deployment_once(
         "docker inspect-digest",
         _patch("dep-ext"),
     ]
+
+
+def test_invalid_tag_fails_before_any_control_plane_call(
+    deploy_project: DeployProject,
+) -> None:
+    result = deploy_project.run("--no-remote", "--tag", "not a tag")
+
+    assert result.exit_code != 0
+    assert "Image tag may only contain" in result.output
+    assert deploy_project.timeline == []