diff --git a/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx b/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx
index 314a5488d..b75967053 100644
--- a/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx
+++ b/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx
@@ -3373,6 +3373,26 @@ export default function CanvasEditorLegacyPage({ params }: PageProps) {
     }
   }, [isAgentMode]);
 
+  useEffect(() => {
+    if (isVideoMode || typeof window === "undefined") return;
+
+    const handleCanvasChatPanelOpenRequest = () => {
+      setPanelMode("chat");
+      setIsPanelOpen(true);
+    };
+
+    window.addEventListener(
+      "canvas-open-chat-panel-request",
+      handleCanvasChatPanelOpenRequest
+    );
+    return () => {
+      window.removeEventListener(
+        "canvas-open-chat-panel-request",
+        handleCanvasChatPanelOpenRequest
+      );
+    };
+  }, [isVideoMode]);
+
   useEffect(() => {
     if (shouldOpenBatchProcessing && isBatchProcessingEnabled) {
       router.replace(`/canvas/${id}/batch`);
diff --git a/components/canvas/CanvasChatPanel.tsx b/components/canvas/CanvasChatPanel.tsx
index 22f897b2f..48b7e3821 100644
--- a/components/canvas/CanvasChatPanel.tsx
+++ b/components/canvas/CanvasChatPanel.tsx
@@ -3594,6 +3594,13 @@ export function CanvasChatPanel({
 
   useEffect(() => {
     if (!effectiveAgentEnabled || typeof window === "undefined") return;
+    type PendingCanvasAgentSlotFillRequest = {
+      nodeId?: string;
+      label?: string;
+    };
+    const targetWindow = window as Window & {
+      __canvasAgentPendingSlotFillRequest?: PendingCanvasAgentSlotFillRequest;
+    };
 
     const focusComposerWithPrompt = (prompt: string) => {
       handleSelectGenerationMode("agent");
@@ -3618,6 +3625,10 @@ export function CanvasChatPanel({
 
     const handleAgentSlotFillRequest = (event: Event) => {
       const detail = (event as CustomEvent<{ nodeId?: string; label?: string }>).detail;
+      const pending = targetWindow.__canvasAgentPendingSlotFillRequest;
+      if (!pending?.nodeId || pending.nodeId === detail?.nodeId) {
+        delete targetWindow.__canvasAgentPendingSlotFillRequest;
+      }
       const label = String(detail?.label || "这个槽位").trim();
       const prompt = `在${label === "这个槽位" ? label : `「${label}」`}生成一张图`;
 
@@ -3660,6 +3671,14 @@ export function CanvasChatPanel({
       "canvas-agent-annotation-edit-request",
       handleAgentAnnotationEditRequest
     );
+    const pendingSlotFillRequest = targetWindow.__canvasAgentPendingSlotFillRequest;
+    if (pendingSlotFillRequest) {
+      handleAgentSlotFillRequest(
+        new CustomEvent("canvas-agent-slot-fill-request", {
+          detail: pendingSlotFillRequest,
+        })
+      );
+    }
     return () => {
       window.removeEventListener(
         "canvas-agent-slot-fill-request",
diff --git a/components/canvas/CanvasWorkspace.tsx b/components/canvas/CanvasWorkspace.tsx
index a9476e3db..fc46ce170 100644
--- a/components/canvas/CanvasWorkspace.tsx
+++ b/components/canvas/CanvasWorkspace.tsx
@@ -687,15 +687,28 @@ export function CanvasWorkspace({
 
   const requestFillAgentSlotFromContextMenu = useCallback(() => {
     if (!agentSlotContextMenu || typeof window === "undefined") return;
+    const detail = {
+      nodeId: agentSlotContextMenu.nodeId,
+      label: agentSlotContextMenu.label,
+    };
+    const targetWindow = window as Window & {
+      __canvasAgentPendingSlotFillRequest?: typeof detail;
+    };
     selectNode(agentSlotContextMenu.nodeId, false);
-    window.dispatchEvent(
-      new CustomEvent("canvas-agent-slot-fill-request", {
+    targetWindow.__canvasAgentPendingSlotFillRequest = detail;
+    targetWindow.dispatchEvent(
+      new CustomEvent("canvas-open-chat-panel-request", {
         detail: {
-          nodeId: agentSlotContextMenu.nodeId,
-          label: agentSlotContextMenu.label,
+          reason: "agent-slot-fill",
+          nodeId: detail.nodeId,
         },
       })
     );
+    targetWindow.dispatchEvent(
+      new CustomEvent("canvas-agent-slot-fill-request", {
+        detail,
+      })
+    );
     setAgentSlotContextMenu(null);
   }, [agentSlotContextMenu, selectNode]);
 
diff --git a/docs/无限画布对话框Agent模式升级开发文档-借鉴Cowart-2026-06-22.md b/docs/无限画布对话框Agent模式升级开发文档-借鉴Cowart-2026-06-22.md
index b60bf54a6..b5a723c12 100644
--- a/docs/无限画布对话框Agent模式升级开发文档-借鉴Cowart-2026-06-22.md
+++ b/docs/无限画布对话框Agent模式升级开发文档-借鉴Cowart-2026-06-22.md
@@ -931,6 +931,7 @@ components/canvas/nodes/AgentSlotNode.tsx
   - “设为图片槽”
   - “设为视频槽”
   - “允许替换 / 保留版本”
+- “填充此槽位”必须同时打开/切回右侧对话面板；若对话面板 lazy 未挂载，需要缓存一次 pending slot fill request，挂载后自动预填槽位生成 prompt。
 
 ### 7.4 工具栏新增 slot 工具
 
@@ -1524,6 +1525,7 @@ lib/ai/runtime/middlewares/canvas-agent-clarification-gate.ts
 - 新增 `AgentSlotNode.tsx`
 - 工具栏增加图片 slot
 - 右键菜单支持“填充此槽位”
+- 槽位右键填充会展开对话框并在面板未挂载时保留 pending request
 - `buildCanvasAgentContext()` 输出 slots
 
 验收：