diff --git a/pytests/A_memorix_test/test_summary_importer_model_config.py b/pytests/A_memorix_test/test_summary_importer_model_config.py
new file mode 100644
index 00000000..845deb08
--- /dev/null
+++ b/pytests/A_memorix_test/test_summary_importer_model_config.py
@@ -0,0 +1,48 @@
+import pytest
+
+from src.A_memorix.core.utils.summary_importer import SummaryImporter
+from src.config.model_configs import TaskConfig
+from src.services import llm_service as llm_api
+
+
+def _fake_available_models() -> dict[str, TaskConfig]:
+    return {
+        "replyer": TaskConfig(
+            model_list=["test-model"],
+            max_tokens=128,
+            temperature=0.7,
+            selection_strategy="priority",
+        )
+    }
+
+
+def test_resolve_summary_model_config_uses_auto_list_when_summarization_missing(monkeypatch):
+    monkeypatch.setattr(llm_api, "get_available_models", _fake_available_models)
+
+    importer = SummaryImporter(
+        vector_store=None,
+        graph_store=None,
+        metadata_store=None,
+        embedding_manager=None,
+        plugin_config={},
+    )
+
+    resolved = importer._resolve_summary_model_config()
+
+    assert resolved is not None
+    assert resolved.model_list == ["test-model"]
+
+
+def test_resolve_summary_model_config_rejects_legacy_string_selector(monkeypatch):
+    monkeypatch.setattr(llm_api, "get_available_models", _fake_available_models)
+
+    importer = SummaryImporter(
+        vector_store=None,
+        graph_store=None,
+        metadata_store=None,
+        embedding_manager=None,
+        plugin_config={"summarization": {"model_name": "auto"}},
+    )
+
+    with pytest.raises(ValueError, match="List\\[str\\]"):
+        importer._resolve_summary_model_config()
diff --git a/src/A_memorix/core/utils/summary_importer.py b/src/A_memorix/core/utils/summary_importer.py
index cea7167c..0728e4dc 100644
--- a/src/A_memorix/core/utils/summary_importer.py
+++ b/src/A_memorix/core/utils/summary_importer.py
@@ -136,7 +136,9 @@ class SummaryImporter:
         if not available_tasks:
             return None
 
-        raw_cfg = self.plugin_config.get("summarization", {}).get("model_name", "auto")
+        # vNext 要求该字段为 List[str]；当配置缺失时回退到 ["auto"]，
+        # 避免默认值本身触发类型校验异常。
+        raw_cfg = self.plugin_config.get("summarization", {}).get("model_name", ["auto"])
         selectors = self._normalize_summary_model_selectors(raw_cfg)
         default_task_name, default_task_cfg = self._pick_default_summary_task(available_tasks)
 
diff --git a/src/A_memorix/scripts/release_vnext_migrate.py b/src/A_memorix/scripts/release_vnext_migrate.py
index d41b755f..49c7517c 100644
--- a/src/A_memorix/scripts/release_vnext_migrate.py
+++ b/src/A_memorix/scripts/release_vnext_migrate.py
@@ -472,7 +472,11 @@ def _migrate_config(config_doc: Dict[str, Any]) -> Dict[str, Any]:
 
     summary = _ensure_table(config_doc, "summarization")
     summary_model = summary.get("model_name", ["auto"])
-    if isinstance(summary_model, str):
+    if "model_name" not in summary:
+        normalized = ["auto"]
+        summary["model_name"] = normalized
+        changes["summarization.model_name"] = {"old": "<missing>", "new": normalized}
+    elif isinstance(summary_model, str):
         normalized = [summary_model.strip() or "auto"]
         summary["model_name"] = normalized
         changes["summarization.model_name"] = {"old": summary_model, "new": normalized}