diff --git a/UI-DESIGN.md b/UI-DESIGN.md
index d4ef9e5a..f3769edd 100644
--- a/UI-DESIGN.md
+++ b/UI-DESIGN.md
@@ -35,6 +35,7 @@
 - 加载、空内容、无结果、失败、只读和权限不足是不同状态，必须分别呈现。
 - 可撤销操作优先提供撤销，不可撤销操作必须在执行前说明影响范围。
 - 不依赖颜色单独表达状态或风险。
+- 当前模型或 Runtime 及切换进度集中显示在会话输入区，顶栏不重复显示可用性标识。切换失败、自动状态检查失败或返回不可用时，通过应用通知说明原因；发送按钮保留关联的无障碍状态说明。
 
 ### 2.5 默认支持浅色与深色主题
 
diff --git a/src/renderer/src/App.test.tsx b/src/renderer/src/App.test.tsx
index a72827fb..04516f07 100644
--- a/src/renderer/src/App.test.tsx
+++ b/src/renderer/src/App.test.tsx
@@ -2109,22 +2109,8 @@ describe("App", () => {
     await screen.findByRole("heading", {
       name: "今天想一起完成什么？",
     });
-    const runtimeStatus =
-      document.querySelector<HTMLElement>(".runtime-status");
-    expect(runtimeStatus).not.toBeNull();
-    expect(within(runtimeStatus!).queryByText("就绪")).not.toBeInTheDocument();
-    expect(runtimeStatus).toHaveClass("runtime-status--ready");
-    expect(
-      runtimeStatus?.querySelector(".runtime-status__dot"),
-    ).toBeInTheDocument();
-    expect(runtimeStatus).toHaveAttribute(
-      "aria-describedby",
-      "topbar-runtime-detail",
-    );
-    expect(screen.getByText("Ready", { selector: ".sr-only" })).toHaveAttribute(
-      "id",
-      "topbar-runtime-detail",
-    );
+    expect(document.querySelector(".runtime-status")).not.toBeInTheDocument();
+    expect(document.getElementById("topbar-runtime-detail")).toBeNull();
     expect(
       screen.getByText(
         /你好，我是 GoodBuddy。你可以直接向我提问、添加本地文件/u,
@@ -2137,14 +2123,24 @@ describe("App", () => {
     ).not.toBeInTheDocument();
   });
 
-  it("uses a compact color indicator while connecting to a Runtime", () => {
+  it("notifies when automatic Runtime status checks fail", async () => {
+    vi.mocked(api.conversations.list).mockResolvedValue([{
+      id: "00000000-0000-4000-8000-000000000951",
+      projectId,
+      title: "Runtime check",
+      updatedAt: Date.now(),
+      messages: [],
+      runtimeSelection: { provider: "opencode" },
+    }]);
+    vi.mocked(api.agent.getStatus).mockImplementation(async (selection) => {
+      if (selection) throw new Error("Runtime status check failed");
+      return { id: "model", label: "sonnet-5", available: true, supportsToolExecution: true, detail: "Ready" };
+    });
     render(<App />);
-    const connectingStatus =
-      document.querySelector<HTMLElement>(".runtime-status");
-    expect(connectingStatus).toHaveClass("runtime-status--connecting");
-    expect(
-      within(connectingStatus!).queryByText("连接中"),
-    ).not.toBeInTheDocument();
+    expect(await screen.findByRole("alert")).toHaveTextContent("Runtime status check failed");
+    const sendButton = screen.getByRole("button", { name: "发送" });
+    expect(sendButton).toBeDisabled();
+    expect(sendButton).toHaveAccessibleDescription("Runtime status check failed");
   });
 
   it("loads customized branding into the primary sidebar", async () => {
diff --git a/src/renderer/src/App.tsx b/src/renderer/src/App.tsx
index 377b4949..2560c69a 100644
--- a/src/renderer/src/App.tsx
+++ b/src/renderer/src/App.tsx
@@ -3952,6 +3952,16 @@ function App(): React.JSX.Element {
         }
         setRuntime(status);
         setRuntimeStatusKey(activeRuntimeSelectionKey);
+        if (!status.available) {
+          notify({
+            tone: "error",
+            message: tRef.current("runtime.selectionUnavailable", {
+              label: status.label,
+              detail: status.detail,
+            }),
+            dedupeKey: "runtime-status",
+          });
+        }
         if (!status.available && !runtimeSetupPromptedRef.current) {
           runtimeSetupPromptedRef.current = true;
           setView("settings");
@@ -3961,19 +3971,20 @@ function App(): React.JSX.Element {
         if (runtimeStatusRequestRef.current !== requestId) {
           return;
         }
+        const detail = reason instanceof Error
+          ? reason.message
+          : tRef.current("runtime.errors.readStatus");
         setRuntime({
           id: "setup",
           label: tRef.current("runtime.unavailable"),
           available: false,
           supportsToolExecution: false,
-          detail:
-            reason instanceof Error
-              ? reason.message
-              : tRef.current("runtime.errors.readStatus"),
+          detail,
         });
         setRuntimeStatusKey(activeRuntimeSelectionKey);
+        notify({ tone: "error", message: detail, dedupeKey: "runtime-status" });
       });
-  }, [activeRuntimeSelectionKey, runtimeSettings, setView]);
+  }, [activeRuntimeSelectionKey, runtimeSettings, setView, notify]);
 
   const startNewConversation = useCallback(
     (projectId?: string, preview?: { ready: (conversation: Conversation) => void }): boolean => {
@@ -8852,7 +8863,7 @@ function App(): React.JSX.Element {
       : runtime.available
         ? "ready"
         : "unavailable";
-  const runtimeDetailId = "topbar-runtime-detail";
+  const runtimeDetailId = "composer-runtime-detail";
   const runtimeDetail =
     runtimeState === "connecting"
       ? t("runtime.connecting")
@@ -9735,24 +9746,6 @@ function App(): React.JSX.Element {
             </>
           )}
           <div className="topbar__actions">
-            <span
-              aria-describedby={runtimeDetailId}
-              className={`runtime-status runtime-status--${runtimeState}`}
-              title={runtimeDetail}
-            >
-              <span className="runtime-status__dot" />
-              <span className="runtime-status__label">
-                {runtime?.label ?? t("runtime.detecting")}
-              </span>
-              {runtime?.capability === "image-generation" && (
-                <span className="runtime-capability-badge">
-                  {t("runtime.imageGeneration")}
-                </span>
-              )}
-            </span>
-            <span className="sr-only" id={runtimeDetailId}>
-              {runtimeDetail}
-            </span>
             <button
               aria-controls="assistant-sidebar"
               aria-expanded={assistantSidebarOpen}
@@ -10829,6 +10822,9 @@ function App(): React.JSX.Element {
                                   />
                                 </button>
                               )}
+                              <span className="sr-only" id={runtimeDetailId}>
+                                {runtimeDetail}
+                              </span>
                               <button
                                 aria-describedby={
                                   runtimeState !== "ready"
diff --git a/src/renderer/src/WorkspacePrimitives.test.tsx b/src/renderer/src/WorkspacePrimitives.test.tsx
index e46f013d..e0c759d6 100644
--- a/src/renderer/src/WorkspacePrimitives.test.tsx
+++ b/src/renderer/src/WorkspacePrimitives.test.tsx
@@ -84,18 +84,6 @@ describe('WorkspacePrimitives', () => {
     cleanup()
   })
 
-  it('uses semantic colors for compact Runtime status dots', () => {
-    expect(stylesheet).toMatch(
-      /\.runtime-status--ready \.runtime-status__dot\s*\{[^}]*background:\s*var\(--success\);/u
-    )
-    expect(stylesheet).toMatch(
-      /\.runtime-status--connecting \.runtime-status__dot\s*\{[^}]*background:\s*var\(--warning\);/u
-    )
-    expect(stylesheet).toMatch(
-      /\.runtime-status--unavailable \.runtime-status__dot\s*\{[^}]*background:\s*var\(--text-muted\);/u
-    )
-  })
-
   it('wraps long model names, prompts, and errors inside shared message status cards', () => {
     expect(stylesheet).toMatch(
       /\.message-retrieval-status\s*\{[^}]*overflow-wrap:\s*anywhere;/u
diff --git a/src/renderer/src/styles.css b/src/renderer/src/styles.css
index 7411f3c4..f9b72c5e 100644
--- a/src/renderer/src/styles.css
+++ b/src/renderer/src/styles.css
@@ -5419,51 +5419,6 @@ button > svg {
   gap: 3px;
 }
 
-.runtime-status {
-  display: flex;
-  min-width: 0;
-  max-width: clamp(108px, 18vw, 220px);
-  align-items: center;
-  padding: 6px 10px;
-  border: 1px solid var(--border-default);
-  border-radius: 8px;
-  margin-right: 8px;
-  background: var(--surface-raised);
-  color: var(--text-secondary);
-  font-size: var(--font-caption);
-  font-weight: 600;
-  gap: 6px;
-}
-
-.runtime-status__dot {
-  flex: 0 0 auto;
-}
-
-.runtime-status__label {
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-}
-
-.runtime-status__dot {
-  width: 6px;
-  height: 6px;
-  border-radius: 50%;
-  background: var(--text-muted);
-}
-
-.runtime-status--ready .runtime-status__dot {
-  background: var(--success);
-}
-
-.runtime-status--connecting .runtime-status__dot {
-  background: var(--warning);
-}
-
-.runtime-status--unavailable .runtime-status__dot {
-  background: var(--text-muted);
-}
-
 .chat-scroll-region {
   position: relative;
   min-height: 0;
@@ -16234,7 +16189,6 @@ details.settings-section > :not(summary) + :not(summary) {
   .user-card,
   .icon-button,
   .assistant-sidebar__row,
-  .runtime-status,
   .welcome__description,
   .tool-activity,
   .context-chip,
@@ -16822,7 +16776,6 @@ details.settings-section > :not(summary) + :not(summary) {
 
   :root :is(
     .task-status-dot,
-    .runtime-status__dot,
     .heartbeat-center__pulse-dot,
     .heartbeat-center__timeline-dot
   ) {