diff --git a/engine/include/XCEngine/Rendering/AGENTS.md b/engine/include/XCEngine/Rendering/AGENTS.md
index 8be3f83b..021b00f6 100644
--- a/engine/include/XCEngine/Rendering/AGENTS.md
+++ b/engine/include/XCEngine/Rendering/AGENTS.md
@@ -205,9 +205,11 @@ Managed SRP assets 通过 `GraphicsSettings.renderPipelineAsset` 选择，并通
 - `ManagedRenderPipelineAssetDescriptor` 标识 managed asset assembly、namespace、class、可选 `AssetRef`、
   serialized ScriptableObject asset graph 和 retained managed object handle。它不再是 configured pipeline
   的唯一身份；`GraphicsSettingsState` 中的 configured `AssetRef` 才是 Unity 风格 asset selection root。
-- Descriptor-only selection 仍保留给测试、legacy runtime fallback 和尚未接入 asset import 的路径。没有
-  `serializedAssetGraph` 时才允许按 class 默认构造 materialize；一旦 snapshot 存在，缺失或失效的
-  managed object handle 必须从 snapshot 重建，不能退回 code-created default asset。
+- Descriptor-only selection 仍保留给测试、legacy runtime fallback 和尚未接入 asset import 的路径；但
+  `GraphicsSettings.renderPipelineAsset` getter 和任何带 `AssetRef` 的 managed runtime path 在没有
+  `serializedAssetGraph` 时都必须显式失败，不能按 class 默认构造 materialize。只有明确的 descriptor-only
+  legacy/test path 才允许 class-default fallback；一旦 snapshot 存在，缺失或失效的 managed object handle
+  必须从 snapshot 重建，不能退回 code-created default asset。
 - `GraphicsSettings.renderPipelineAsset = asset` 必须把当前 managed SRP asset graph snapshot 收进 descriptor。
   该 snapshot 覆盖 `UniversalRenderPipelineAsset -> ScriptableRendererData -> ScriptableRendererFeature`
   以及 public/`[SerializeField]` serializable settings。Runtime cache 更新可以替换 handle，但不得丢失
@@ -392,7 +394,8 @@ Scene data 每个 camera frame 提取一次，然后由 pipeline 调整。
   assembly/type/handle runtime cache，managed materialization 更新 cache 时保留 configured asset reference。
 - Managed SRP descriptor 已接入 serialized ScriptableObject graph snapshot。`GraphicsSettings` setter 保存
   当前 asset/data/features 图，getter 和 `MonoManagedRenderPipelineAssetRuntime` 在 handle 缺失或失效时按
-  snapshot 重建；无 snapshot 的 descriptor-only selection 才保留 class 默认构造 fallback。
+  snapshot 重建；`GraphicsSettings` getter 与任何带 `AssetRef` 的 runtime path 不再接受无 snapshot 的
+  class 默认构造，只有 descriptor-only legacy/test path 保留该 fallback。
 - Managed SRP execution 由 `ScriptableRenderPipelineHost` 承载，它组合 native backend 和可选 managed
   stage recorder。
 - Mono-backed SRP assets 使用 `DefaultNativeBackend` 做 scene drawing，并把 managed stages 记录到 native
diff --git a/engine/src/Scripting/Mono/MonoScriptRuntime.cpp b/engine/src/Scripting/Mono/MonoScriptRuntime.cpp
index 9aa22c79..a0d300a1 100644
--- a/engine/src/Scripting/Mono/MonoScriptRuntime.cpp
+++ b/engine/src/Scripting/Mono/MonoScriptRuntime.cpp
@@ -3013,6 +3013,13 @@ bool MonoManagedRenderPipelineAssetRuntime::EnsureManagedAsset() const {
         return m_ownsManagedAssetHandle;
     }
 
+    if (m_descriptor.HasAssetRef()) {
+        m_runtime->SetError(
+            "Managed render pipeline asset selected by AssetRef has no serialized asset graph; refusing class-default materialization: " +
+            m_descriptor.GetFullName() + ".");
+        return false;
+    }
+
     MonoClass* assetClass = nullptr;
     if (!m_runtime->ResolveManagedClass(
             m_descriptor.assemblyName,
@@ -9063,27 +9070,10 @@ bool MonoScriptRuntime::TryEnsureManagedRenderPipelineAssetHandle(
         return true;
     }
 
-    MonoClass* assetClass = nullptr;
-    if (!ResolveManagedClass(
-            ioDescriptor.assemblyName,
-            ioDescriptor.namespaceName,
-            ioDescriptor.className,
-            assetClass) ||
-        assetClass == nullptr) {
-        return false;
-    }
-
-    if (!IsMonoClassOrSubclass(
-            assetClass,
-            m_scriptableRenderPipelineAssetClass)) {
-        SetError(
-            "Managed render pipeline asset must derive from ScriptableRenderPipelineAsset: " +
-            ioDescriptor.GetFullName() + ".");
-        return false;
-    }
-
-    return CreateExternalManagedObject(assetClass, ioDescriptor.managedAssetHandle) &&
-           ioDescriptor.managedAssetHandle != 0u;
+    SetError(
+        "Configured managed render pipeline asset has no serialized asset graph; refusing GraphicsSettings class-default materialization: " +
+        ioDescriptor.GetFullName() + ".");
+    return false;
 }
 
 void MonoScriptRuntime::DestroyExternalManagedObject(uint32_t gcHandle) {
diff --git a/tests/scripting/test_mono_script_runtime.cpp b/tests/scripting/test_mono_script_runtime.cpp
index cae40da1..d0472058 100644
--- a/tests/scripting/test_mono_script_runtime.cpp
+++ b/tests/scripting/test_mono_script_runtime.cpp
@@ -127,6 +127,16 @@ MonoScriptRuntime::Settings CreateMonoSettings() {
     return settings;
 }
 
+XCEngine::Resources::AssetRef MakeRenderPipelineAssetRefForTest(
+    uint64_t guidLow = 2u) {
+    XCEngine::Resources::AssetRef assetRef = {};
+    assetRef.assetGuid = XCEngine::Resources::AssetGUID(1u, guidLow);
+    assetRef.localID = XCEngine::Resources::kMainAssetLocalID;
+    assetRef.resourceType =
+        XCEngine::Resources::ResourceType::RenderPipelineAsset;
+    return assetRef;
+}
+
 class MonoScriptRuntimeTest : public ::testing::Test {
 protected:
     void SetUp() override {
@@ -478,7 +488,7 @@ TEST_F(
 
 TEST_F(
     MonoScriptRuntimeTest,
-    ManagedGraphicsSettingsGetterMaterializesConfiguredAssetWithoutExistingHandle) {
+    ManagedGraphicsSettingsGetterRejectsDescriptorOnlyAssetWithoutSerializedGraph) {
     Scene* runtimeScene =
         CreateScene("ManagedRenderPipelineGetterMaterializationScene");
     GameObject* scriptObject =
@@ -507,11 +517,7 @@ TEST_F(
     EXPECT_EQ(resolvedDescriptor.assemblyName, configuredDescriptor.assemblyName);
     EXPECT_EQ(resolvedDescriptor.namespaceName, configuredDescriptor.namespaceName);
     EXPECT_EQ(resolvedDescriptor.className, configuredDescriptor.className);
-    EXPECT_NE(resolvedDescriptor.managedAssetHandle, 0u);
-    EXPECT_NE(
-        runtime->GetExternalManagedObject(
-            resolvedDescriptor.managedAssetHandle),
-        nullptr);
+    EXPECT_EQ(resolvedDescriptor.managedAssetHandle, 0u);
 
     bool observedAssetWasNull = true;
     std::string observedPipelineAssetTypeName;
@@ -519,14 +525,18 @@ TEST_F(
         script,
         "ObservedAssetWasNull",
         observedAssetWasNull));
-    EXPECT_FALSE(observedAssetWasNull);
+    EXPECT_TRUE(observedAssetWasNull);
     EXPECT_TRUE(runtime->TryGetFieldValue(
         script,
         "ObservedPipelineAssetTypeName",
         observedPipelineAssetTypeName));
-    EXPECT_EQ(
-        observedPipelineAssetTypeName,
-        "Gameplay.RenderPipelineApiProbeAsset");
+    EXPECT_TRUE(observedPipelineAssetTypeName.empty());
+    EXPECT_NE(
+        runtime->GetLastError().find("serialized asset graph"),
+        std::string::npos);
+    EXPECT_NE(
+        runtime->GetLastError().find("GraphicsSettings"),
+        std::string::npos);
 }
 
 TEST_F(
@@ -679,6 +689,36 @@ TEST_F(
     EXPECT_FLOAT_EQ(observedFinalColorScale.w, 1.0f);
 }
 
+TEST_F(
+    MonoScriptRuntimeTest,
+    ManagedRenderPipelineAssetRuntimeRejectsAssetRefWithoutSerializedGraph) {
+    const auto bridge =
+        XCEngine::Rendering::Pipelines::GetManagedRenderPipelineBridge();
+    ASSERT_NE(bridge, nullptr);
+
+    XCEngine::Rendering::Pipelines::ManagedRenderPipelineAssetDescriptor
+        descriptor = {
+            "GameScripts",
+            "Gameplay",
+            "ManagedRenderPipelineProbeAsset"
+        };
+    descriptor.assetRef = MakeRenderPipelineAssetRefForTest(17u);
+
+    std::shared_ptr<const XCEngine::Rendering::Pipelines::
+                        ManagedRenderPipelineAssetRuntime>
+        assetRuntime = bridge->CreateAssetRuntime(descriptor);
+    ASSERT_NE(assetRuntime, nullptr);
+
+    XCEngine::Rendering::FinalColorSettings settings = {};
+    EXPECT_FALSE(assetRuntime->TryGetDefaultFinalColorSettings(settings));
+    EXPECT_NE(
+        runtime->GetLastError().find("AssetRef"),
+        std::string::npos);
+    EXPECT_NE(
+        runtime->GetLastError().find("serialized asset graph"),
+        std::string::npos);
+}
+
 TEST_F(
     MonoScriptRuntimeTest,
     RuntimeStopClearsManagedGraphicsSettingsSelection) {