diff --git a/AGENTS.md b/AGENTS.md
index 41ed756..329b42c 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -5,6 +5,7 @@
 函数定义 函数调用 等参数不允许换行 注意所有facade用到的函数名都定义在这里 D:
 \ae\proj\Aethera\kernel\kernel\include\global.hpp 这样重复的名称不用重复写 光写facade即可
 
+枚举定义要换行 加注释 facade_builder 定义也要换行
 ``
 除非特别说明不允许写任何同步等待代码。
 除非特别说明不允许写任何同步等待代码。
@@ -26,7 +27,9 @@
 除非特别说明不允许写任何 快照， 任何线程问题先完了都要给我说明 我来审核。
 ``
 
-跨模块多态对象统一使用 proxy 表达，proxy 的实际所有权由构造时承载的指针类型决定：裸指针为非拥有借用，make_proxy/unique_ptr 为独占所有权，make_proxy_shared/shared_ptr 为共享所有权，proxy_view 为非拥有观察，weak_proxy 为弱所有权。接口和字段注释必须写明实际所有权与生命周期，不再强制使用 not_null<T*> 或 owner<T*> 标注普通指针。
+跨模块多态对象统一使用 proxy 表达，proxy 的实际所有权由构造时承载的指针类型决定：裸指针为非拥有借用，make_proxy/unique_ptr
+为独占所有权，make_proxy_shared/shared_ptr 为共享所有权，proxy_view 为非拥有观察，weak_proxy
+为弱所有权。接口和字段注释必须写明实际所有权与生命周期，不再强制使用 not_null<T*> 或 owner<T*> 标注普通指针。
 
 我使用 里的这个环境 D:\ae\proj\Aethera\CMakePresets.json  "toolchain/vs2022.json"
 ====================[ 构建 | Aethera_Kernel_check | vs2022_debug ]================
diff --git a/kernel/kernel/module/frame_policy/export/export.h b/kernel/kernel/module/frame_policy/export/export.h
index 15cb846..d4d234b 100644
--- a/kernel/kernel/module/frame_policy/export/export.h
+++ b/kernel/kernel/module/frame_policy/export/export.h
@@ -1,12 +1,24 @@
 #pragma once
 #include <cstdint>
-
+#include <variant>
 namespace aethera {
-enum struct Frame_Policy_Configuration_Result : std::uint8_t { invalid_user_frame_rate, interval_out_of_range, invalid_statistics_window };
-enum struct Frame_Policy_Render_Submission_Result : std::uint8_t { runtime_not_initialized, task_graph_invalid };
-enum struct Throttled_Latest_Only_Start_Result : std::uint8_t { already_running, start_in_progress, stop_in_progress, dependency_unavailable, frame_unavailable, invalid_user_frame_rate, interval_out_of_range, invalid_statistics_window };
-enum struct Throttled_Latest_Only_Stop_Result : std::uint8_t { already_stopped, already_stopping, start_in_progress, completion_missing };
-namespace frame_policy {
-enum struct Render_Scene_Result : std::uint8_t { submitted, runtime_not_initialized, task_graph_invalid, frame_missing, completion_missing };
-} // namespace frame_policy
+enum struct Frame_Policy_Configuration_Result : std::uint8_t {
+    invalid_user_frame_rate,
+    interval_out_of_range,
+    invalid_statistics_window
+};
+enum struct Throttled_Latest_Only_Start_State_Result : std::uint8_t {
+    already_running,
+    start_in_progress,
+    stop_in_progress,
+    dependency_unavailable,
+    frame_unavailable
+};
+using Throttled_Latest_Only_Start_Result = std::variant<Throttled_Latest_Only_Start_State_Result, Frame_Policy_Configuration_Result>;
+enum struct Throttled_Latest_Only_Stop_Result : std::uint8_t {
+    already_stopped,
+    already_stopping,
+    start_in_progress,
+    completion_missing
+};
 } // namespace aethera
diff --git a/kernel/kernel/module/frame_policy/rely_facade.h b/kernel/kernel/module/frame_policy/rely_facade.h
index 2083f11..844d9ae 100644
--- a/kernel/kernel/module/frame_policy/rely_facade.h
+++ b/kernel/kernel/module/frame_policy/rely_facade.h
@@ -1,19 +1,17 @@
 #pragma once
 #include "export/export.h"
 #include "global.hpp"
+#include "scene/export/export.h"
 #include "time_thread/export/export.h"
-#include <exception>
 #include <functional>
 #include <proxy/proxy.h>
 
 namespace aethera::frame_policy {
 using Timer_Id = aethera::Timer_Id;
 using Timer_Callback = aethera::Timer_Callback;
-struct Frame : facade_builder::build {};
-using Frame_Completion = std::function<void(proxy<Frame>&)>;
-using Render_Completion = std::function<void(proxy<Frame>&, std::exception_ptr)>;
-struct Scene : facade_builder::add_convention<_create_frame, proxy<Frame>()>::add_convention<_render, Render_Scene_Result(proxy<Frame>&, Render_Completion)>::support_relocation<pro::constraint_level::nothrow>::build {};
-struct Sink : facade_builder::add_convention<_send, void(proxy<Frame>&, Frame_Completion)>::support_relocation<pro::constraint_level::nothrow>::build {};
+using Frame_Completion = std::function<void(proxy<scene::Frame>&)>;
+struct Scene : facade_builder::add_convention<_create_frame, proxy<scene::Frame>()>::add_convention<_render, scene::Render_Result(proxy<scene::Frame>&, scene::Render_Completion)>::support_relocation<pro::constraint_level::nothrow>::build {};
+struct Sink : facade_builder::add_convention<_send, void(proxy<scene::Frame>&, Frame_Completion)>::support_relocation<pro::constraint_level::nothrow>::build {};
 using Timer_Service = time_thread::Timer_Service_Frame_Facade;
 proxy<Timer_Service> make_timer_service();
 } // namespace aethera::frame_policy
diff --git a/kernel/kernel/module/frame_policy/src/Frame_Policy.hpp b/kernel/kernel/module/frame_policy/src/Frame_Policy.hpp
index 9c59a4e..964f837 100644
--- a/kernel/kernel/module/frame_policy/src/Frame_Policy.hpp
+++ b/kernel/kernel/module/frame_policy/src/Frame_Policy.hpp
@@ -1,5 +1,6 @@
 #pragma once
 #include "../export/export.h"
+#include "scene/export/export.h"
 #include "concurrent/base/Concurrent_Struct.hpp"
 #include "model/Model.hpp"
 #include "statistics/Sliding_Statistics.hpp"
@@ -35,7 +36,7 @@ struct Frame_Policy_State {
     Statistics_Summary send_time_ns; /* 发送耗时滑动统计，单位纳秒。 */
     Statistics_Summary end_to_end_time_ns; /* 渲染开始至发送完成耗时统计，单位纳秒。 */
     std::optional<Frame_Policy_Configuration_Result> configuration_error; /* 动态配置无效时记录原因；有效时为空。 */
-    std::optional<Frame_Policy_Render_Submission_Result> render_submission_error; /* Scene 拒绝最近一次渲染提交时的策略级原因；下一次提交成功后清空。 */
+    std::optional<scene::Render_Error> render_submission_error; /* Scene 拒绝最近一次渲染提交时的原始原因；下一次提交成功后清空。 */
 };
 } // namespace aethera
 #include "Frame_Policy.ipp"
diff --git a/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.cpp b/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.cpp
index 12be7fd..2c1891c 100644
--- a/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.cpp
+++ b/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.cpp
@@ -1,5 +1,6 @@
 #include "Throttled_Latest_Only.hpp"
 #include <algorithm>
+#include <concepts>
 #include <exception>
 #include <utility>
 namespace aethera {
@@ -7,16 +8,6 @@ namespace {
 auto positive_duration(std::chrono::steady_clock::duration duration) noexcept -> std::chrono::nanoseconds {
     return std::max(std::chrono::nanoseconds{1}, std::chrono::duration_cast<std::chrono::nanoseconds>(duration));
 }
-auto start_result(Frame_Policy::Configuration_Result result) noexcept -> Throttled_Latest_only::Start_Result {
-    using Configuration_Result = Frame_Policy::Configuration_Result;
-    using Start_Result = Throttled_Latest_only::Start_Result;
-    switch (result) {
-    case Configuration_Result::invalid_user_frame_rate: return Start_Result::invalid_user_frame_rate;
-    case Configuration_Result::interval_out_of_range: return Start_Result::interval_out_of_range;
-    case Configuration_Result::invalid_statistics_window: return Start_Result::invalid_statistics_window;
-    }
-    std::terminate();
-}
 } // namespace
 Throttled_Latest_only::Throttled_Latest_only(proxy<frame_policy::Timer_Service> timer_service, proxy<frame_policy::Scene> scene, proxy<frame_policy::Sink> sink) : Def(std::move(timer_service), std::move(scene), std::move(sink)) {}
 Throttled_Latest_only::~Throttled_Latest_only() noexcept {
@@ -53,23 +44,23 @@ auto Throttled_Latest_only::Private::prepare_start() -> std::expected<std::chron
     {
         std::lock_guard lock(mutex);
         switch (phase) {
-        case Phase::running: return std::unexpected(Start_Result::already_running);
-        case Phase::starting: return std::unexpected(Start_Result::start_in_progress);
-        case Phase::stopping: return std::unexpected(Start_Result::stop_in_progress);
+        case Phase::running: return std::unexpected(Start_Result{Start_State_Result::already_running});
+        case Phase::starting: return std::unexpected(Start_Result{Start_State_Result::start_in_progress});
+        case Phase::stopping: return std::unexpected(Start_Result{Start_State_Result::stop_in_progress});
         case Phase::stopped: break;
         }
         if (!timer_service || !scene || !sink) {
-            return std::unexpected(Start_Result::dependency_unavailable);
+            return std::unexpected(Start_Result{Start_State_Result::dependency_unavailable});
         }
         phase = Phase::starting;
     }
-    std::array<proxy<frame_policy::Frame>, Frame_Count> created_frames;
+    std::array<proxy<scene::Frame>, Frame_Count> created_frames;
     try {
         for (auto& created_frame : created_frames) {
             created_frame = scene->create_frame();
             if (!created_frame) {
                 rollback_start();
-                return std::unexpected(Start_Result::frame_unavailable);
+                return std::unexpected(Start_Result{Start_State_Result::frame_unavailable});
             }
         }
         std::lock_guard lock(mutex);
@@ -84,7 +75,7 @@ auto Throttled_Latest_only::Private::prepare_start() -> std::expected<std::chron
         publish_state();
         if (!interval) {
             phase = Phase::stopped;
-            return std::unexpected(start_result(interval.error()));
+            return std::unexpected(Start_Result{interval.error()});
         }
         for (std::size_t index = 0; index < Frame_Count; ++index) {
             if (frames[index].frame) {
@@ -101,7 +92,7 @@ auto Throttled_Latest_only::Private::prepare_start() -> std::expected<std::chron
     }
 }
 void Throttled_Latest_only::Private::rollback_start() {
-    std::array<proxy<frame_policy::Frame>, Frame_Count> retired_frames;
+    std::array<proxy<scene::Frame>, Frame_Count> retired_frames;
     {
         std::lock_guard lock(mutex);
         if (phase != Phase::starting || timer_id) {
@@ -220,7 +211,7 @@ void Throttled_Latest_only::Private::frame_due() {
         return;
     }
     try {
-        const auto result = scene->render(frames[selected_index].frame, [this, selected_index](proxy<frame_policy::Frame>& completed_frame, std::exception_ptr failure) {
+        const auto result = scene->render(frames[selected_index].frame, [this, selected_index](proxy<scene::Frame>& completed_frame, std::exception_ptr failure) {
             if (failure) {
                 abandon_render(selected_index);
                 std::rethrow_exception(failure);
@@ -228,29 +219,30 @@ void Throttled_Latest_only::Private::frame_due() {
             rendered(selected_index, completed_frame);
         });
         record_render_submission(result);
-        if (result != frame_policy::Render_Scene_Result::submitted) abandon_render(selected_index);
+        if (!result) abandon_render(selected_index);
     }
     catch (...) {
         abandon_render(selected_index);
         throw;
     }
 }
-void Throttled_Latest_only::Private::record_render_submission(frame_policy::Render_Scene_Result result) {
+void Throttled_Latest_only::Private::record_render_submission(scene::Render_Result result) {
     std::lock_guard lock(mutex);
     auto& state = *get<Frame_Policy_State>().internal.use();
-    switch (result) {
-    case frame_policy::Render_Scene_Result::submitted: state.render_submission_error.reset();
-        break;
-    case frame_policy::Render_Scene_Result::runtime_not_initialized: state.render_submission_error = Frame_Policy_Render_Submission_Result::runtime_not_initialized;
-        break;
-    case frame_policy::Render_Scene_Result::task_graph_invalid: state.render_submission_error = Frame_Policy_Render_Submission_Result::task_graph_invalid;
-        break;
-    case frame_policy::Render_Scene_Result::frame_missing:
-    case frame_policy::Render_Scene_Result::completion_missing: std::terminate();
+    if (result) state.render_submission_error.reset();
+    else {
+        const bool impossible = std::visit([](auto error) {
+            using Error = decltype(error);
+            if constexpr (std::same_as<Error, scene::Render_State_Result>) return true;
+            if constexpr (std::same_as<Error, Run_Taskflow_Result>) return error == Run_Taskflow_Result::completion_missing || error == Run_Taskflow_Result::observation_unavailable;
+            return false;
+        }, result.error());
+        if (impossible) std::terminate();
+        state.render_submission_error = result.error();
     }
     publish_state();
 }
-void Throttled_Latest_only::Private::rendered(std::size_t slot_index, proxy<frame_policy::Frame>& completed_frame) {
+void Throttled_Latest_only::Private::rendered(std::size_t slot_index, proxy<scene::Frame>& completed_frame) {
     bool dispatch = false;
     {
         std::lock_guard lock(mutex);
@@ -298,7 +290,7 @@ void Throttled_Latest_only::Private::rendered(std::size_t slot_index, proxy<fram
 }
 void Throttled_Latest_only::Private::dispatch_send(std::size_t slot_index) {
     try {
-        sink->send(frames[slot_index].frame, [this, slot_index](proxy<frame_policy::Frame>& completed_frame) {
+        sink->send(frames[slot_index].frame, [this, slot_index](proxy<scene::Frame>& completed_frame) {
             sent(slot_index, completed_frame);
         });
     }
@@ -307,7 +299,7 @@ void Throttled_Latest_only::Private::dispatch_send(std::size_t slot_index) {
         throw;
     }
 }
-void Throttled_Latest_only::Private::sent(std::size_t slot_index, proxy<frame_policy::Frame>& completed_frame) {
+void Throttled_Latest_only::Private::sent(std::size_t slot_index, proxy<scene::Frame>& completed_frame) {
     std::size_t next_send_index = Frame_Count;
     {
         std::lock_guard lock(mutex);
@@ -361,7 +353,7 @@ void Throttled_Latest_only::Private::abandon_send(std::size_t slot_index) {
     finish_stop_if_ready();
 }
 void Throttled_Latest_only::Private::finish_stop_if_ready() {
-    std::array<proxy<frame_policy::Frame>, Frame_Count> retired_frames;
+    std::array<proxy<scene::Frame>, Frame_Count> retired_frames;
     Stop_Completion completion;
     {
         std::lock_guard lock(mutex);
diff --git a/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.hpp b/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.hpp
index dc187f5..77b3805 100644
--- a/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.hpp
+++ b/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.hpp
@@ -11,6 +11,7 @@ namespace aethera {
  */
 struct Throttled_Latest_only : Def<Throttled_Latest_only, Frame_Policy> {
     using Start_Result = Throttled_Latest_Only_Start_Result;
+    using Start_State_Result = Throttled_Latest_Only_Start_State_Result;
     using Stop_Result = Throttled_Latest_Only_Stop_Result;
     using Stop_Completion = std::function<void()>;
     struct Private;
diff --git a/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.ipp b/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.ipp
index 31aed00..daba79b 100644
--- a/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.ipp
+++ b/kernel/kernel/module/frame_policy/src/Throttled_Latest_Only.ipp
@@ -18,7 +18,7 @@ struct Throttled_Latest_only::Private : Prev_Private {
         sending
     };
     struct Frame_Slot {
-        proxy<frame_policy::Frame> frame; /* 帧池在本槽唯一拥有并循环复用的物理帧。 */
+        proxy<scene::Frame> frame; /* 帧池在本槽唯一拥有并循环复用的物理帧。 */
         Frame_Phase phase{Frame_Phase::idle}; /* 本槽当前用途的唯一权威状态。 */
         std::chrono::steady_clock::time_point render_start; /* 当前帧开始渲染的单调时刻。 */
         std::chrono::steady_clock::time_point send_start; /* 当前帧开始发送的单调时刻。 */
@@ -35,10 +35,10 @@ private:
     void cancel_failed();
     void timer_cancelled();
     void frame_due();
-    void record_render_submission(frame_policy::Render_Scene_Result result);
-    void rendered(std::size_t slot_index, proxy<frame_policy::Frame>& completed_frame);
+    void record_render_submission(scene::Render_Result result);
+    void rendered(std::size_t slot_index, proxy<scene::Frame>& completed_frame);
     void dispatch_send(std::size_t slot_index);
-    void sent(std::size_t slot_index, proxy<frame_policy::Frame>& completed_frame);
+    void sent(std::size_t slot_index, proxy<scene::Frame>& completed_frame);
     void abandon_render(std::size_t slot_index);
     void abandon_send(std::size_t slot_index);
     void finish_stop_if_ready();
diff --git a/kernel/kernel/module/frame_policy/test/Throttled_Latest_Only_Tests.cpp b/kernel/kernel/module/frame_policy/test/Throttled_Latest_Only_Tests.cpp
index f1ef64f..7fabf7b 100644
--- a/kernel/kernel/module/frame_policy/test/Throttled_Latest_Only_Tests.cpp
+++ b/kernel/kernel/module/frame_policy/test/Throttled_Latest_Only_Tests.cpp
@@ -18,12 +18,12 @@ namespace {
 using namespace std::chrono_literals;
 
 struct Pending_Frame {
-    std::reference_wrapper<aethera::proxy<aethera::frame_policy::Frame>> frame; /* 被 Scene/Sink 借用的策略帧。 */
+    std::reference_wrapper<aethera::proxy<aethera::scene::Frame>> frame; /* 被 Scene/Sink 借用的策略帧。 */
     aethera::frame_policy::Frame_Completion completion;                         /* 归还同一帧的完成回调所有权。 */
 };
 struct Pending_Render_Frame {
-    std::reference_wrapper<aethera::proxy<aethera::frame_policy::Frame>> frame; /* Borrowed policy frame; the policy outlives the pending render. */
-    aethera::frame_policy::Render_Completion completion;                        /* Owns the render completion until this frame is returned. */
+    std::reference_wrapper<aethera::proxy<aethera::scene::Frame>> frame; /* Borrowed policy frame; the policy outlives the pending render. */
+    aethera::scene::Render_Completion completion;                        /* Owns the render completion until this frame is returned. */
 };
 
 struct Frame_Policy_Test_Control {
@@ -55,7 +55,7 @@ struct Frame_Policy_Test_Control {
 
     std::deque<Pending_Render_Frame> rendering_frames; /* Scene 尚未归还的帧及其回调。 */
     std::deque<Pending_Frame> sending_frames;   /* Sink 尚未归还的帧及其回调。 */
-    std::vector<aethera::proxy<aethera::frame_policy::Frame>*>
+    std::vector<aethera::proxy<aethera::scene::Frame>*>
         rendered_frame_addresses;                    /* 可空、非拥有；记录每次渲染采用的槽位地址。 */
     aethera::frame_policy::Timer_Callback timer_callback; /* 周期服务持有的到期回调。 */
     aethera::frame_policy::Timer_Callback cancel_completion; /* 测试显式完成异步取消的回调。 */
@@ -66,7 +66,7 @@ struct Frame_Policy_Test_Control {
     std::size_t frames_alive{};                      /* 尚未析构的物理帧数量。 */
     std::size_t render_calls{};                      /* Scene 已接受的渲染借用次数。 */
     std::size_t send_calls{};                        /* Sink 已接受的发送借用次数。 */
-    aethera::frame_policy::Render_Scene_Result render_result{aethera::frame_policy::Render_Scene_Result::submitted}; /* Scene 对下一次及后续渲染提交返回的结果。 */
+    aethera::scene::Render_Result render_result{}; /* Scene 对下一次及后续渲染提交返回的原始结果。 */
     std::exception_ptr render_failure{};             /* Failure delivered by the next render completion. */
     bool complete_render_synchronously{};            /* Scene 是否在 render 内立即归还帧。 */
     bool complete_send_synchronously{};              /* Sink 是否在 send 内立即归还帧。 */
@@ -122,21 +122,21 @@ struct Test_Scene : aethera::Def<Test_Scene, aethera::Root> {
 struct Test_Scene::Private : Prev_Private {
     explicit Private(std::shared_ptr<Frame_Policy_Test_Control> control) : control(std::move(control)) {}
 
-    aethera::proxy<aethera::frame_policy::Frame> create_frame() {
+    aethera::proxy<aethera::scene::Frame> create_frame() {
         ++control->frames_created;
-        return pro::make_proxy<aethera::frame_policy::Frame, Test_Frame>(control);
+        return pro::make_proxy<aethera::scene::Frame, Test_Frame>(control);
     }
 
-    aethera::frame_policy::Render_Scene_Result render(aethera::proxy<aethera::frame_policy::Frame>& frame, aethera::frame_policy::Render_Completion completion) {
+    aethera::scene::Render_Result render(aethera::proxy<aethera::scene::Frame>& frame, aethera::scene::Render_Completion completion) {
         control->rendered_frame_addresses.push_back(std::addressof(frame));
         ++control->render_calls;
-        if (control->render_result != aethera::frame_policy::Render_Scene_Result::submitted) return control->render_result;
+        if (!control->render_result) return control->render_result;
         if (control->complete_render_synchronously) {
             completion(frame, std::exchange(control->render_failure, {}));
-            return aethera::frame_policy::Render_Scene_Result::submitted;
+            return {};
         }
         control->rendering_frames.push_back({frame, std::move(completion)});
-        return aethera::frame_policy::Render_Scene_Result::submitted;
+        return {};
     }
 
     std::shared_ptr<Frame_Policy_Test_Control> control; /* Scene 测试行为的共享控制数据。 */
@@ -150,7 +150,7 @@ struct Test_Sink : aethera::Def<Test_Sink, aethera::Root> {
 struct Test_Sink::Private : Prev_Private {
     explicit Private(std::shared_ptr<Frame_Policy_Test_Control> control) : control(std::move(control)) {}
 
-    void send(aethera::proxy<aethera::frame_policy::Frame>& frame, aethera::frame_policy::Frame_Completion completion) {
+    void send(aethera::proxy<aethera::scene::Frame>& frame, aethera::frame_policy::Frame_Completion completion) {
         ++control->send_calls;
         if (control->throw_from_send) {
             throw std::runtime_error("test sink failure");
@@ -183,10 +183,10 @@ TEST(Throttled_Latest_Only, Publishes_And_Clears_Scene_Submission_Failure) {
     auto control = std::make_shared<Frame_Policy_Test_Control>();
     auto policy = make_policy(control);
     ASSERT_TRUE(policy->start().has_value());
-    control->render_result = aethera::frame_policy::Render_Scene_Result::runtime_not_initialized;
+    control->render_result = std::unexpected(aethera::scene::Render_Error{aethera::Run_Taskflow_Result::runtime_not_initialized});
     control->fire_timer();
-    policy->read<aethera::Export_Struct, aethera::Frame_Policy_State>([](const aethera::Frame_Policy_State& state) { ASSERT_TRUE(state.render_submission_error.has_value()); EXPECT_EQ(*state.render_submission_error, aethera::Frame_Policy_Render_Submission_Result::runtime_not_initialized); });
-    control->render_result = aethera::frame_policy::Render_Scene_Result::submitted;
+    policy->read<aethera::Export_Struct, aethera::Frame_Policy_State>([](const aethera::Frame_Policy_State& state) { ASSERT_TRUE(state.render_submission_error.has_value()); EXPECT_EQ(std::get<aethera::Run_Taskflow_Result>(*state.render_submission_error), aethera::Run_Taskflow_Result::runtime_not_initialized); });
+    control->render_result = aethera::scene::Render_Result{};
     control->fire_timer();
     policy->read<aethera::Export_Struct, aethera::Frame_Policy_State>([](const aethera::Frame_Policy_State& state) { EXPECT_FALSE(state.render_submission_error.has_value()); });
     control->complete_render();
@@ -432,7 +432,7 @@ TEST(Throttled_Latest_Only, Reports_Invalid_Configuration) {
     auto missing_dependencies = missing_builder.build();
     const auto missing_start = missing_dependencies->start();
     ASSERT_FALSE(missing_start);
-    EXPECT_EQ(missing_start.error(), aethera::Throttled_Latest_only::Start_Result::dependency_unavailable);
+    EXPECT_EQ(std::get<aethera::Throttled_Latest_only::Start_State_Result>(missing_start.error()), aethera::Throttled_Latest_only::Start_State_Result::dependency_unavailable);
     const auto missing_stop = missing_dependencies->stop({});
     ASSERT_FALSE(missing_stop);
     EXPECT_EQ(missing_stop.error(), aethera::Throttled_Latest_only::Stop_Result::completion_missing);
@@ -441,20 +441,20 @@ TEST(Throttled_Latest_Only, Reports_Invalid_Configuration) {
     auto policy = make_policy(control, 0.0);
     const auto invalid_rate = policy->start();
     ASSERT_FALSE(invalid_rate);
-    EXPECT_EQ(invalid_rate.error(), aethera::Throttled_Latest_only::Start_Result::invalid_user_frame_rate);
+    EXPECT_EQ(std::get<aethera::Frame_Policy_Configuration_Result>(invalid_rate.error()), aethera::Frame_Policy_Configuration_Result::invalid_user_frame_rate);
     auto tiny_rate = make_policy(control, std::numeric_limits<double>::denorm_min());
     const auto invalid_interval = tiny_rate->start();
     ASSERT_FALSE(invalid_interval);
-    EXPECT_EQ(invalid_interval.error(), aethera::Throttled_Latest_only::Start_Result::interval_out_of_range);
+    EXPECT_EQ(std::get<aethera::Frame_Policy_Configuration_Result>(invalid_interval.error()), aethera::Frame_Policy_Configuration_Result::interval_out_of_range);
 
     auto invalid_statistics = make_policy(control, 60.0, false, false, true, 0);
     const auto invalid_statistics_result = invalid_statistics->start();
     ASSERT_FALSE(invalid_statistics_result);
-    EXPECT_EQ(invalid_statistics_result.error(), aethera::Throttled_Latest_only::Start_Result::invalid_statistics_window);
+    EXPECT_EQ(std::get<aethera::Frame_Policy_Configuration_Result>(invalid_statistics_result.error()), aethera::Frame_Policy_Configuration_Result::invalid_statistics_window);
     auto invalid_adaptive_window = make_policy(control, std::nullopt, true, false, false, 0);
     const auto invalid_adaptive_result = invalid_adaptive_window->start();
     ASSERT_FALSE(invalid_adaptive_result);
-    EXPECT_EQ(invalid_adaptive_result.error(), aethera::Throttled_Latest_only::Start_Result::invalid_statistics_window);
+    EXPECT_EQ(std::get<aethera::Frame_Policy_Configuration_Result>(invalid_adaptive_result.error()), aethera::Frame_Policy_Configuration_Result::invalid_statistics_window);
 }
 
 TEST(Throttled_Latest_Only, Render_Failure_Releases_Slot_Before_It_Escapes) {
diff --git a/kernel/kernel/module/main.cmake b/kernel/kernel/module/main.cmake
index 64db0aa..c8ada79 100644
--- a/kernel/kernel/module/main.cmake
+++ b/kernel/kernel/module/main.cmake
@@ -16,11 +16,11 @@ aethera_kernel_add_module(Aethera_Kernel_Time_Thread time_thread)
 add_library(Aethera_Kernel::Time_Thread ALIAS Aethera_Kernel_Time_Thread)
 target_link_libraries(Aethera_Kernel_Time_Thread PRIVATE Threads::Threads)
 
-aethera_kernel_add_module(Aethera_Kernel_Frame_Policy frame_policy Aethera_Kernel_Time_Thread)
-add_library(Aethera_Kernel::Frame_Policy ALIAS Aethera_Kernel_Frame_Policy)
-
 aethera_kernel_add_module(Aethera_Kernel_Renderable renderable Aethera_Kernel_Task_Flow)
 add_library(Aethera_Kernel::Renderable ALIAS Aethera_Kernel_Renderable)
 
-aethera_kernel_add_module(Aethera_Kernel_Scene scene Aethera_Kernel_Task_Flow Aethera_Kernel_Renderable Aethera_Kernel_Frame_Policy)
+aethera_kernel_add_module(Aethera_Kernel_Scene scene Aethera_Kernel_Task_Flow)
 add_library(Aethera_Kernel::Scene ALIAS Aethera_Kernel_Scene)
+
+aethera_kernel_add_module(Aethera_Kernel_Frame_Policy frame_policy Aethera_Kernel_Time_Thread)
+add_library(Aethera_Kernel::Frame_Policy ALIAS Aethera_Kernel_Frame_Policy)
diff --git a/kernel/kernel/module/scene/export/export.h b/kernel/kernel/module/scene/export/export.h
index 584c814..d9b810b 100644
--- a/kernel/kernel/module/scene/export/export.h
+++ b/kernel/kernel/module/scene/export/export.h
@@ -1,6 +1,19 @@
 #pragma once
+#include "global.hpp"
+#include "task_flow/export/export.h"
 #include <cstdint>
-
-namespace aethera {
-enum struct Scene_Create_Taskflow_Result : std::uint8_t { component_unavailable, dependency_cycle, already_composed, dependency_unavailable };
-} // namespace aethera
+#include <exception>
+#include <expected>
+#include <functional>
+#include <proxy/proxy.h>
+#include <variant>
+namespace aethera::scene {
+struct Frame : facade_builder::build {};
+using Render_Completion = std::function<void(proxy<Frame>&, std::exception_ptr)>;
+enum struct Render_State_Result : std::uint8_t {
+    frame_missing,
+    completion_missing
+};
+using Render_Error = std::variant<Render_State_Result, Compose_Task_Graph_Result, Precede_Task_Graph_Result, Run_Taskflow_Result>;
+using Render_Result = std::expected<void, Render_Error>;
+} // namespace aethera::scene
diff --git a/kernel/kernel/module/scene/src/Scene.cpp b/kernel/kernel/module/scene/src/Scene.cpp
index f95d0fc..655bb24 100644
--- a/kernel/kernel/module/scene/src/Scene.cpp
+++ b/kernel/kernel/module/scene/src/Scene.cpp
@@ -9,42 +9,36 @@ struct Scene_Frame {};
 }
 proxy<scene::Task_Graph> scene::make_task_graph(std::string name) { return task_flow::make_task_graph(std::move(name)); }
 Scene::Private::Private() = default;
-proxy<frame_policy::Frame> Scene::Private::create_frame() {
-    return pro::make_proxy<frame_policy::Frame, detail::Scene_Frame>();
+proxy<scene::Frame> Scene::Private::create_frame() {
+    return pro::make_proxy<scene::Frame, detail::Scene_Frame>();
 }
 proxy<scene::Task_Graph>& Scene::Private::taskflow() {
     return graph;
 }
-auto Scene::Private::create_taskflow() -> std::expected<proxy<scene::Task_Graph>, Create_Taskflow_Result> {
+auto Scene::Private::create_taskflow() -> std::expected<proxy<scene::Task_Graph>, Create_Taskflow_Error> {
     auto result = scene::make_task_graph("scene.renderables");
     std::unordered_map<std::uint64_t, proxy<task_flow::Task_Node>> nodes;
     auto& renderables = get<Scene_Renderable_Dag>().internal.use();
-    std::optional<Create_Taskflow_Result> error;
+    std::optional<Create_Taskflow_Error> error;
     renderables.for_each_topological([&](Dag_Node_Id id, proxy<scene::Renderable>& renderable) {
         if (error) return;
         auto component = renderable->taskflow();
         auto composed = result->compose("renderable." + std::to_string(id.value), component);
         if (!composed) {
-            switch (composed.error()) {
-            case Compose_Task_Graph_Result::component_unavailable: error = Create_Taskflow_Result::component_unavailable;
-                break;
-            case Compose_Task_Graph_Result::dependency_cycle: error = Create_Taskflow_Result::dependency_cycle;
-                break;
-            case Compose_Task_Graph_Result::already_composed: error = Create_Taskflow_Result::already_composed;
-                break;
-            }
+            error = composed.error();
             return;
         }
         nodes.emplace(id.value, std::move(*composed));
     });
     if (error) return std::unexpected(*error);
     renderables.for_each_dependency([&](Dag_Node_Id target, Dag_Node_Id source) {
-        if (result->precede(nodes.at(source.value), nodes.at(target.value)) != Precede_Task_Graph_Result::preceded) error = Create_Taskflow_Result::dependency_unavailable;
+        const auto dependency = result->precede(nodes.at(source.value), nodes.at(target.value));
+        if (dependency != Precede_Task_Graph_Result::preceded) error = dependency;
     });
     if (error) return std::unexpected(*error);
     return result;
 }
-auto Scene::Private::advance() -> std::expected<void, Create_Taskflow_Result> {
+auto Scene::Private::advance() -> std::expected<void, Create_Taskflow_Error> {
     auto& renderables = get<Scene_Renderable_Dag>();
     renderables.internal.advance();
     renderables.internal.use().for_each_topological([](Dag_Node_Id, proxy<scene::Renderable>& renderable) {
@@ -55,20 +49,16 @@ auto Scene::Private::advance() -> std::expected<void, Create_Taskflow_Result> {
     graph = std::move(*next_graph);
     return {};
 }
-frame_policy::Render_Scene_Result Scene::Private::render(proxy<frame_policy::Frame>& frame, frame_policy::Render_Completion completion) {
-    if (!frame) return frame_policy::Render_Scene_Result::frame_missing;
-    if (!completion) return frame_policy::Render_Scene_Result::completion_missing;
-    if (!advance()) return frame_policy::Render_Scene_Result::task_graph_invalid;
+scene::Render_Result Scene::Private::render(proxy<scene::Frame>& frame, scene::Render_Completion completion) {
+    if (!frame) return std::unexpected(scene::Render_Error{scene::Render_State_Result::frame_missing});
+    if (!completion) return std::unexpected(scene::Render_Error{scene::Render_State_Result::completion_missing});
+    const auto advanced = advance();
+    if (!advanced) return std::unexpected(std::visit([](auto error) -> scene::Render_Error { return error; }, advanced.error()));
     const auto result = graph->run([frame = std::ref(frame), completion = std::move(completion)](std::exception_ptr failure) mutable {
         completion(frame.get(), std::move(failure));
     });
-    switch (result) {
-    case Run_Taskflow_Result::submitted: return frame_policy::Render_Scene_Result::submitted;
-    case Run_Taskflow_Result::runtime_not_initialized: return frame_policy::Render_Scene_Result::runtime_not_initialized;
-    case Run_Taskflow_Result::completion_missing: return frame_policy::Render_Scene_Result::completion_missing;
-    case Run_Taskflow_Result::observation_unavailable: std::terminate();
-    }
-    std::terminate();
+    if (result != Run_Taskflow_Result::submitted) return std::unexpected(scene::Render_Error{result});
+    return {};
 }
 Scene::Scene() = default;
 Scene::~Scene() noexcept = default;
diff --git a/kernel/kernel/module/scene/src/Scene.hpp b/kernel/kernel/module/scene/src/Scene.hpp
index 9e91ea3..3c529e9 100644
--- a/kernel/kernel/module/scene/src/Scene.hpp
+++ b/kernel/kernel/module/scene/src/Scene.hpp
@@ -1,6 +1,5 @@
 #pragma once
 #include "../export/export.h"
-#include "frame_policy/rely_facade.h"
 #include "model/Model.hpp"
 #include "relation/Dag.hpp"
 #include <functional>
diff --git a/kernel/kernel/module/scene/src/Scene.ipp b/kernel/kernel/module/scene/src/Scene.ipp
index fccafa1..45b1b03 100644
--- a/kernel/kernel/module/scene/src/Scene.ipp
+++ b/kernel/kernel/module/scene/src/Scene.ipp
@@ -1,13 +1,14 @@
 #pragma once
+#include <variant>
 namespace aethera {
 struct Scene::Private : Prev_Private {
-    using Create_Taskflow_Result = Scene_Create_Taskflow_Result;
+    using Create_Taskflow_Error = std::variant<Compose_Task_Graph_Result, Precede_Task_Graph_Result>;
     Private();
-    proxy<frame_policy::Frame> create_frame();
-    frame_policy::Render_Scene_Result render(proxy<frame_policy::Frame>& frame, frame_policy::Render_Completion completion);
+    proxy<scene::Frame> create_frame();
+    scene::Render_Result render(proxy<scene::Frame>& frame, scene::Render_Completion completion);
     proxy<scene::Task_Graph>& taskflow();
-    auto create_taskflow() -> std::expected<proxy<scene::Task_Graph>, Create_Taskflow_Result>;
-    auto advance() -> std::expected<void, Create_Taskflow_Result>;
+    auto create_taskflow() -> std::expected<proxy<scene::Task_Graph>, Create_Taskflow_Error>;
+    auto advance() -> std::expected<void, Create_Taskflow_Error>;
 private:
     proxy<scene::Task_Graph> graph{scene::make_task_graph("scene")}; /* 唯一拥有当前组合任务图的跨模块代理。 */
 };
diff --git a/kernel/kernel/module/scene/test/Scene_Tests.cpp b/kernel/kernel/module/scene/test/Scene_Tests.cpp
index 664f3fb..5a1fe24 100644
--- a/kernel/kernel/module/scene/test/Scene_Tests.cpp
+++ b/kernel/kernel/module/scene/test/Scene_Tests.cpp
@@ -19,8 +19,6 @@ struct Test_Dag_Renderable : aethera::Def<Test_Dag_Renderable, aethera::Renderab
         int id{};
     };
 };
-static_assert(pro::proxiable<aethera::detail::Model_Private_Pointer<aethera::Scene*>, aethera::frame_policy::Scene>);
-
 TEST(Scene, Advances_Renderables_And_Composes_Task_Graph_In_Dag_Order) {
     auto advance_order = std::make_shared<std::vector<int>>();
     aethera::Dag<aethera::scene::Renderable>::Builder builder;
@@ -81,11 +79,17 @@ TEST(Scene, Render_Returns_Known_Submission_Result) {
     aethera::Scene scene;
     auto frame = scene.d->create_frame();
     bool completed{};
-    EXPECT_EQ(scene.d->render(frame, [&](aethera::proxy<aethera::frame_policy::Frame>&, std::exception_ptr) { completed = true; }), aethera::frame_policy::Render_Scene_Result::runtime_not_initialized);
+    const auto unavailable_runtime = scene.d->render(frame, [&](aethera::proxy<aethera::scene::Frame>&, std::exception_ptr) { completed = true; });
+    ASSERT_FALSE(unavailable_runtime);
+    EXPECT_EQ(std::get<aethera::Run_Taskflow_Result>(unavailable_runtime.error()), aethera::Run_Taskflow_Result::runtime_not_initialized);
     EXPECT_FALSE(completed);
-    aethera::proxy<aethera::frame_policy::Frame> empty_frame;
-    EXPECT_EQ(scene.d->render(empty_frame, [&](aethera::proxy<aethera::frame_policy::Frame>&, std::exception_ptr) {}), aethera::frame_policy::Render_Scene_Result::frame_missing);
-    EXPECT_EQ(scene.d->render(frame, {}), aethera::frame_policy::Render_Scene_Result::completion_missing);
+    aethera::proxy<aethera::scene::Frame> empty_frame;
+    const auto missing_frame = scene.d->render(empty_frame, [&](aethera::proxy<aethera::scene::Frame>&, std::exception_ptr) {});
+    ASSERT_FALSE(missing_frame);
+    EXPECT_EQ(std::get<aethera::scene::Render_State_Result>(missing_frame.error()), aethera::scene::Render_State_Result::frame_missing);
+    const auto missing_completion = scene.d->render(frame, {});
+    ASSERT_FALSE(missing_completion);
+    EXPECT_EQ(std::get<aethera::scene::Render_State_Result>(missing_completion.error()), aethera::scene::Render_State_Result::completion_missing);
 }
 
 TEST(Scene, Rejects_The_Same_Renderable_Task_Graph_Twice) {
@@ -98,6 +102,8 @@ TEST(Scene, Rejects_The_Same_Renderable_Task_Graph_Twice) {
     aethera::Scene scene;
     scene.write<aethera::Owned_Dag, aethera::Scene_Renderable_Dag>(std::move(*graph));
     auto frame = scene.d->create_frame();
-    EXPECT_EQ(scene.d->render(frame, [](aethera::proxy<aethera::frame_policy::Frame>&, std::exception_ptr) {}), aethera::frame_policy::Render_Scene_Result::task_graph_invalid);
+    const auto rendered = scene.d->render(frame, [](aethera::proxy<aethera::scene::Frame>&, std::exception_ptr) {});
+    ASSERT_FALSE(rendered);
+    EXPECT_EQ(std::get<aethera::Compose_Task_Graph_Result>(rendered.error()), aethera::Compose_Task_Graph_Result::already_composed);
 }
 } // namespace
diff --git a/kernel/kernel/module/task_flow/export/export.h b/kernel/kernel/module/task_flow/export/export.h
index 8ddda4b..90f54a1 100644
--- a/kernel/kernel/module/task_flow/export/export.h
+++ b/kernel/kernel/module/task_flow/export/export.h
@@ -6,25 +6,70 @@
 #include <functional>
 #include <proxy/proxy.h>
 #include <string>
-
 namespace aethera {
-enum struct Add_Task_Graph_Result : std::uint8_t { work_missing };
-enum struct Add_Condition_Task_Graph_Result : std::uint8_t { condition_missing };
-enum struct Compose_Task_Graph_Result : std::uint8_t { component_unavailable, dependency_cycle, already_composed };
-enum struct Precede_Task_Graph_Result : std::uint8_t { preceded, node_unavailable, node_stale, different_graph };
-enum struct Describe_Task_Graph_Result : std::uint8_t { described, key_missing };
-enum struct Describe_Task_Graph_Node_Result : std::uint8_t { described, node_unavailable, node_stale, key_missing };
-enum struct Run_Taskflow_Result : std::uint8_t { submitted, runtime_not_initialized, completion_missing, observation_unavailable };
-enum struct Taskflow_Unknown_Failure_Policy : std::uint8_t { fast_fail, exception };
-enum struct Initialize_Task_Runtime_Result : std::uint8_t { initialized, invalid_worker_count, exception_boundary_missing, exception_boundary_unexpected, already_initialized, initialization_in_progress };
-enum struct Take_Taskflow_Observation_Result : std::uint8_t { not_recorded, recording, already_taken };
+enum struct Add_Task_Graph_Result : std::uint8_t {
+    work_missing
+};
+enum struct Add_Condition_Task_Graph_Result : std::uint8_t {
+    condition_missing
+};
+enum struct Compose_Task_Graph_Result : std::uint8_t {
+    component_unavailable,
+    dependency_cycle,
+    already_composed
+};
+enum struct Precede_Task_Graph_Result : std::uint8_t {
+    preceded,
+    node_unavailable,
+    node_stale,
+    different_graph
+};
+enum struct Describe_Task_Graph_Result : std::uint8_t {
+    described,
+    key_missing
+};
+enum struct Describe_Task_Graph_Node_Result : std::uint8_t {
+    described,
+    node_unavailable,
+    node_stale,
+    key_missing
+};
+enum struct Run_Taskflow_Result : std::uint8_t {
+    submitted,
+    runtime_not_initialized,
+    completion_missing,
+    observation_unavailable
+};
+enum struct Taskflow_Unknown_Failure_Policy : std::uint8_t {
+    fast_fail,
+    exception
+};
+enum struct Initialize_Task_Runtime_Result : std::uint8_t {
+    initialized,
+    invalid_worker_count,
+    exception_boundary_missing,
+    exception_boundary_unexpected,
+    already_initialized,
+    initialization_in_progress
+};
+enum struct Take_Taskflow_Observation_Result : std::uint8_t {
+    not_recorded,
+    recording,
+    already_taken
+};
 using Taskflow_Completion = std::function<void(std::exception_ptr)>;
 using Taskflow_Exception_Boundary = std::function<void(std::exception_ptr)>;
 namespace task_flow {
 struct Task_Node : facade_builder::add_skill<pro::skills::rtti>::build {};
 struct Task_Graph_Component : facade_builder::add_skill<pro::skills::rtti>::build {};
-struct Task_Graph_Common_Facade : facade_builder::add_convention<_component, proxy<Task_Graph_Component>()>::add_convention<_empty, bool() const noexcept>::support_relocation<pro::constraint_level::nothrow>::build {};
-struct Task_Graph_Build_Facade : facade_builder::add_facade_with_substitution<Task_Graph_Common_Facade>::add_convention<_add, std::expected<proxy<Task_Node>, Add_Task_Graph_Result>(std::string, std::function<void()>)>::add_convention<_clear, void()>::build {};
+struct Task_Graph_Common_Facade : facade_builder
+::add_convention<_component, proxy<Task_Graph_Component>()>
+::add_convention<_empty, bool() const noexcept>
+::support_relocation<pro::constraint_level::nothrow>
+::build {};
+struct Task_Graph_Build_Facade : facade_builder::add_facade_with_substitution<Task_Graph_Common_Facade>
+::add_convention<_add, std::expected<proxy<Task_Node>, Add_Task_Graph_Result>(std::string, std::function<void()>)>
+::add_convention<_clear, void()>::build {};
 struct Task_Graph_Compose_Facade : facade_builder::add_facade_with_substitution<Task_Graph_Common_Facade>::add_convention<_compose, std::expected<proxy<Task_Node>, Compose_Task_Graph_Result>(std::string, proxy<Task_Graph_Component>&)>::add_convention<_precede, Precede_Task_Graph_Result(proxy<Task_Node>&, proxy<Task_Node>&)>::add_convention<_run, Run_Taskflow_Result(Taskflow_Completion)>::build {};
 struct Task_Graph_Facade : facade_builder::add_facade_with_substitution<Task_Graph_Build_Facade>::add_facade_with_substitution<Task_Graph_Compose_Facade>::build {};
 proxy<Task_Graph_Facade> make_task_graph(std::string name);