diff --git a/components/canvas/CanvasChatPanel.tsx b/components/canvas/CanvasChatPanel.tsx
index 759a3b92e..1494e029d 100644
--- a/components/canvas/CanvasChatPanel.tsx
+++ b/components/canvas/CanvasChatPanel.tsx
@@ -311,6 +311,14 @@ interface CanvasChatPanelProps {
 
 type CanvasComposerMode = "agent" | "image" | "video" | "detail" | "clawd";
 
+function getCanvasComposerModeSessionLabel(mode: CanvasComposerMode) {
+  if (mode === "clawd") return "Clawd";
+  if (mode === "video") return "视频";
+  if (mode === "detail") return "AI详情";
+  if (mode === "image") return "图像";
+  return "Agent";
+}
+
 type VideoStoryboardStreamData =
   | {
       stage: "detecting";
@@ -1321,6 +1329,7 @@ export function CanvasChatPanel({
     () => requestedChatSessionId || chatId
   );
   const activeChatIdRef = useRef<string>(requestedChatSessionId || chatId);
+  const activeMessagesRef = useRef<ChatMessage[]>([]);
   const inFlightChatIdRef = useRef<string | null>(null);
   const inFlightRawChatIdRef = useRef<string | null>(null);
   const [chatSessions, setChatSessions] = useState<CanvasChatSession[]>([]);
@@ -1528,6 +1537,29 @@ export function CanvasChatPanel({
     );
   }, [getSendGuard]);
 
+  const startNewChatSession = useCallback(
+    (options?: { title?: string; toastMessage?: string }) => {
+      const now = Date.now();
+      const newChatSessionId = `canvas-${crypto.randomUUID()}`;
+      const fallbackTitle = `对话 ${chatSessions.length + 1}`;
+      const newSession: CanvasChatSession = {
+        id: newChatSessionId,
+        title: options?.title || fallbackTitle,
+        createdAt: now,
+        updatedAt: now,
+      };
+
+      forceHistoryHydrationRef.current = null;
+      releaseSendGuard(activeChatId);
+      setChatSessions((prevSessions) => [newSession, ...prevSessions]);
+      setActiveChatId(newChatSessionId);
+      replaceChatSessionQuery(newChatSessionId);
+      toast.success(options?.toastMessage || "已新建聊天窗口");
+      return newChatSessionId;
+    },
+    [activeChatId, chatSessions.length, releaseSendGuard, replaceChatSessionQuery]
+  );
+
   const handleTypewriterActiveChange = useCallback((typingKey: string, active: boolean) => {
     setActiveTypingSections((prev) => {
       if (active) {
@@ -3479,6 +3511,21 @@ export function CanvasChatPanel({
           : isPresetAgentSelection
             ? getToolbarItem("chatModePresetAgent").label
             : "Agent";
+  const hasActiveChatContext = useCallback(() => {
+    const editorText = (textareaRef.current?.textContent || "")
+      .replace(/\u200b/g, " ")
+      .replace(/\s+/g, " ")
+      .trim();
+    const hasDetailSlotContent = detailSlots.some((slot) => Boolean(slot?.url));
+    return (
+      activeMessagesRef.current.length > 0 ||
+      Boolean(input.trim()) ||
+      Boolean(editorText) ||
+      attachments.length > 0 ||
+      Boolean(selectedSkillTagId) ||
+      hasDetailSlotContent
+    );
+  }, [attachments.length, detailSlots, input, selectedSkillTagId]);
   const getComposerModeMenuItemClass = useCallback(
     (mode: CanvasComposerMode) =>
       cn(
@@ -3801,6 +3848,58 @@ export function CanvasChatPanel({
         toast.error("Clawd 未开启");
         return;
       }
+      if (mode === "agent") {
+        if (!effectiveAgentEnabled) {
+          return;
+        }
+      }
+      if (mode === "detail" && !canUseDetailGeneration) {
+        toast.error("AI详情生成功能未开启");
+        return;
+      }
+
+      const preferredImageModelId =
+        mode === "image"
+          ? allModels.find(
+              (model) =>
+                model.id === lastImageModelId &&
+                model.id !== "auto" &&
+                isCanvasImageModel(model) &&
+                !model.isMultimodal
+            )?.id || firstImageModelId
+          : null;
+      if (mode === "image" && !preferredImageModelId) {
+        toast.error("当前没有可用的图像模型");
+        return;
+      }
+
+      const preferredVideoModelId =
+        mode === "video"
+          ? allModels.find((model) => model.id === lastVideoModelId && isCanvasVideoModel(model))?.id ||
+            firstVideoModelId
+          : null;
+      if (mode === "video" && !preferredVideoModelId) {
+        toast.error("当前没有可用的视频模型");
+        return;
+      }
+
+      const isSwitchingMode = mode !== activeComposerMode;
+      if (
+        isSwitchingMode &&
+        (getSendGuard(activeChatId).inFlight || isClawdSubmitting || isDetailGenerating)
+      ) {
+        toast.message("当前对话正在处理中，完成后再切换模式");
+        return;
+      }
+
+      if (isSwitchingMode && hasActiveChatContext()) {
+        const modeLabel = getCanvasComposerModeSessionLabel(mode);
+        startNewChatSession({
+          title: `${modeLabel} 对话`,
+          toastMessage: `已为 ${modeLabel} 新建聊天窗口`,
+        });
+      }
+
       activeComposerModeRef.current = mode;
       setComposerModeOverride(mode);
 
@@ -3810,9 +3909,6 @@ export function CanvasChatPanel({
       }
 
       if (mode === "agent") {
-        if (!effectiveAgentEnabled) {
-          return;
-        }
         const preferredAgentModelId =
           allModels.find(
             (model) =>
@@ -3826,10 +3922,6 @@ export function CanvasChatPanel({
       }
 
       if (mode === "detail") {
-        if (!canUseDetailGeneration) {
-          toast.error("AI详情生成功能未开启");
-          return;
-        }
         const detailModelId = effectiveAgentEnabled ? "auto" : "";
         currentModelIdRef.current = detailModelId;
         setSelectedModelId(detailModelId);
@@ -3839,35 +3931,16 @@ export function CanvasChatPanel({
       }
 
       if (mode === "image") {
-        const preferredImageModelId =
-          allModels.find(
-            (model) =>
-              model.id === lastImageModelId &&
-              model.id !== "auto" &&
-              isCanvasImageModel(model) &&
-              !model.isMultimodal
-          )?.id || firstImageModelId;
-
-        if (!preferredImageModelId) {
-          toast.error("当前没有可用的图像模型");
-          return;
-        }
-        currentModelIdRef.current = preferredImageModelId;
-        setSelectedModelId(preferredImageModelId);
+        const nextImageModelId = preferredImageModelId || "";
+        currentModelIdRef.current = nextImageModelId;
+        setSelectedModelId(nextImageModelId);
         setIsDetailGenerationMode(false);
         return;
       }
 
-      const preferredVideoModelId =
-        allModels.find((model) => model.id === lastVideoModelId && isCanvasVideoModel(model))?.id ||
-        firstVideoModelId;
-
-      if (!preferredVideoModelId) {
-        toast.error("当前没有可用的视频模型");
-        return;
-      }
-      currentModelIdRef.current = preferredVideoModelId;
-      setSelectedModelId(preferredVideoModelId);
+      const nextVideoModelId = preferredVideoModelId || "";
+      currentModelIdRef.current = nextVideoModelId;
+      setSelectedModelId(nextVideoModelId);
       setIsDetailGenerationMode(false);
     },
     [
@@ -3875,16 +3948,21 @@ export function CanvasChatPanel({
       effectiveAgentEnabled,
       isClawdModeEnabled,
       allModels,
-      computedComposerMode,
+      activeChatId,
+      activeComposerMode,
       firstImageModelId,
       firstVideoModelId,
-      hasSelectedAgentPreset,
+      getSendGuard,
+      hasActiveChatContext,
+      isClawdSubmitting,
+      isDetailGenerating,
       lastConversationModelId,
       lastImageModelId,
       isCanvasConversationOnlyModel,
       isCanvasImageModel,
       isCanvasVideoModel,
       lastVideoModelId,
+      startNewChatSession,
     ]
   );
 
@@ -5262,6 +5340,10 @@ export function CanvasChatPanel({
     },
   });
 
+  useEffect(() => {
+    activeMessagesRef.current = messages;
+  }, [messages]);
+
   useEffect(() => {
     if (status === "ready") {
       releaseSendGuard(activeChatId);
@@ -10126,22 +10208,8 @@ export function CanvasChatPanel({
   );
 
   const createNewChatSession = useCallback(() => {
-    const now = Date.now();
-    const newChatSessionId = `canvas-${crypto.randomUUID()}`;
-    const fallbackTitle = `对话 ${chatSessions.length + 1}`;
-    const newSession: CanvasChatSession = {
-      id: newChatSessionId,
-      title: fallbackTitle,
-      createdAt: now,
-      updatedAt: now,
-    };
-
-    releaseSendGuard(activeChatId);
-    setChatSessions((prevSessions) => [newSession, ...prevSessions]);
-    setActiveChatId(newChatSessionId);
-    replaceChatSessionQuery(newChatSessionId);
-    toast.success("已新建聊天窗口");
-  }, [activeChatId, chatSessions.length, releaseSendGuard, replaceChatSessionQuery]);
+    startNewChatSession();
+  }, [startNewChatSession]);
 
   const switchToSession = useCallback((sessionId: string) => {
     if (!sessionId || sessionId === activeChatId) {