diff --git a/docs/【编辑器】画布Agent对话面板-2026-07-03.md b/docs/【编辑器】画布Agent对话面板-2026-07-03.md
index 63749082d..e20029467 100644
--- a/docs/【编辑器】画布Agent对话面板-2026-07-03.md
+++ b/docs/【编辑器】画布Agent对话面板-2026-07-03.md
@@ -60,6 +60,7 @@
 - 对话框与左侧素材 / 图层侧栏**不互斥**，允许同时展开，便于在对话中选取和核对画布素材；左侧栏切换不改变 Agent 面板开关状态。
 - 桌面端对话框固定宽约 360–400px；移动端抽屉式全宽覆盖；收起态为胶囊/圆形入口按钮。
 - 会话管理入口在对话框头部：当前会话标题 + 历史会话下拉（按更新时间倒序）+ 新建对话按钮，全部包在对话框内。
+- 当前会话没有任何已发送消息时，新建对话按钮置灰且不可点击；输入框草稿和未发送附件不算会话内容。当前会话已有消息时可新建，新建成功后切换到返回的空白会话并清空输入文字、附件及附件选择状态，旧会话继续保留在历史会话下拉中；创建失败时保留当前会话和未发送内容。
 - 快速切换会话或会话轮询刷新产生并发详情请求时，前端只允许最后发起的请求更新当前会话、消息、错误和加载态；旧响应不得覆盖用户最新选择。
 - 普通 JSON 消息请求的回包必须绑定发送时的会话：用户在等待期间切换到其他会话后，只更新原会话的列表摘要，不得把原会话的 `deltaMessages` 、错误或画布刷新副作用应用到当前面板。
 - 收起对话框只是隐藏面板，不卸载当前会话 hook；普通 JSON 消息请求的等待态和外部生成任务状态必须在收起 / 重新打开之间保持一致。
diff --git a/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.test.tsx b/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.test.tsx
index 3072fa16c..03fdc0a8a 100644
--- a/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.test.tsx
+++ b/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.test.tsx
@@ -264,13 +264,55 @@ describe('EditorAgentConversationPanelView', () => {
       expect(screen.getByText('已经看到画布内容')).toBeTruthy();
     });
 
-    fireEvent.click(screen.getByRole('button', { name: '新建对话' }));
+    const newConversationButton = screen.getByRole('button', {
+      name: '新建对话',
+    }) as HTMLButtonElement;
+    expect(newConversationButton.disabled).toBe(false);
+    fireEvent.change(screen.getByLabelText('发送给画布 Agent'), {
+      target: { value: '不应带入新会话的草稿' },
+    });
+    fireEvent.click(screen.getByRole('button', { name: '添加附件' }));
+    let attachmentDialog = screen.getByRole('dialog', {
+      name: '选择图片附件',
+    });
+    fireEvent.click(
+      within(attachmentDialog).getByRole('checkbox', {
+        name: '选择画布图片 角色图层',
+      }),
+    );
+    fireEvent.click(
+      within(attachmentDialog).getByRole('button', { name: '应用' }),
+    );
+    expect(screen.getByText('角色图层')).toBeTruthy();
+
+    fireEvent.click(newConversationButton);
     await waitFor(() => {
       expect(client.createConversation).toHaveBeenCalledWith('project-1', {});
     });
+    await waitFor(() => {
+      expect(
+        (screen.getByLabelText('当前对话') as HTMLSelectElement).value,
+      ).toBe('conversation-2');
+      expect(newConversationButton.disabled).toBe(true);
+    });
+    expect(
+      (screen.getByLabelText('发送给画布 Agent') as HTMLTextAreaElement).value,
+    ).toBe('');
+    expect(screen.queryByText('角色图层')).toBeNull();
+    expect(
+      screen.getByRole('option', { name: '角色参考' }),
+    ).toBeTruthy();
+    expect(screen.getByRole('option', { name: '新对话' })).toBeTruthy();
+
+    fireEvent.change(screen.getByLabelText('发送给画布 Agent'), {
+      target: { value: '尚未发送的草稿' },
+    });
+    expect(newConversationButton.disabled).toBe(true);
+    fireEvent.click(newConversationButton);
+    expect(client.createConversation).toHaveBeenCalledTimes(1);
 
     fireEvent.click(screen.getByRole('button', { name: '添加附件' }));
-    const attachmentDialog = screen.getByRole('dialog', {
+    attachmentDialog = screen.getByRole('dialog', {
       name: '选择图片附件',
     });
     expect(attachmentDialog.parentElement?.className).toContain(
@@ -315,6 +357,69 @@ describe('EditorAgentConversationPanelView', () => {
     );
   });
 
+  it('keeps new conversation disabled when the project has no conversation history', async () => {
+    const client = createClient();
+    vi.mocked(client.listConversations).mockResolvedValueOnce([]);
+
+    render(
+      <EditorAgentConversationPanelView
+        open
+        onToggleOpen={vi.fn()}
+        client={client}
+      />,
+    );
+
+    await waitFor(() => {
+      expect(client.listConversations).toHaveBeenCalledWith('project-1');
+      expect(screen.getByText('暂无消息')).toBeTruthy();
+    });
+    const newConversationButton = screen.getByRole('button', {
+      name: '新建对话',
+    }) as HTMLButtonElement;
+    expect(newConversationButton.disabled).toBe(true);
+
+    fireEvent.change(screen.getByLabelText('发送给画布 Agent'), {
+      target: { value: '未发送内容' },
+    });
+    expect(newConversationButton.disabled).toBe(true);
+    fireEvent.click(newConversationButton);
+    expect(client.createConversation).not.toHaveBeenCalled();
+  });
+
+  it('preserves the current conversation draft when creating a conversation fails', async () => {
+    const client = createClient();
+    vi.mocked(client.createConversation).mockRejectedValueOnce(
+      new Error('创建新会话失败'),
+    );
+
+    render(
+      <EditorAgentConversationPanelView
+        open
+        onToggleOpen={vi.fn()}
+        client={client}
+      />,
+    );
+
+    await waitFor(() => {
+      expect(screen.getByText('已经看到画布内容')).toBeTruthy();
+    });
+    fireEvent.change(screen.getByLabelText('发送给画布 Agent'), {
+      target: { value: '需要保留的草稿' },
+    });
+    fireEvent.click(screen.getByRole('button', { name: '新建对话' }));
+
+    await waitFor(() => {
+      expect(screen.getByText('创建新会话失败')).toBeTruthy();
+    });
+    expect(
+      (screen.getByLabelText('发送给画布 Agent') as HTMLTextAreaElement).value,
+    ).toBe('需要保留的草稿');
+    expect(screen.getByText('已经看到画布内容')).toBeTruthy();
+    expect(
+      (screen.getByLabelText('当前对话') as HTMLSelectElement).value,
+    ).toBe('conversation-1');
+  });
+
   it('disables sending while a message request is pending without showing stop', async () => {
     const client = createClient();
     let resolveSend!: (response: EditorAgentMessageResponse) => void;
diff --git a/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.tsx b/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.tsx
index 073da2c3b..80ae0a832 100644
--- a/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.tsx
+++ b/src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.tsx
@@ -307,6 +307,19 @@ export function EditorAgentConversationPanelView({
 
   const hasProject = Boolean(projectId?.trim());
   const isConversationBusy = isWaiting || isToolCallActionPending;
+  const hasCurrentConversationContent = messages.length > 0;
+
+  const handleCreateConversation = () => {
+    void createConversation()
+      .then(() => {
+        setDraftText('');
+        setAttachments([]);
+        setAttachmentError(null);
+        setDraftAttachmentKeys(new Set());
+        setAttachmentPickerOpen(false);
+      })
+      .catch(() => undefined);
+  };
 
   const openAttachmentPicker = () => {
     setAttachmentError(null);
@@ -546,9 +559,15 @@ export function EditorAgentConversationPanelView({
             className="inline-flex h-9 w-9 items-center justify-center rounded-full bg-slate-900 text-white disabled:opacity-45"
             aria-label="新建对话"
             disabled={
-              !hasProject || isCreatingConversation || isConversationBusy
+              !hasProject ||
+              !hasCurrentConversationContent ||
+              isLoadingConversations ||
+              isLoadingMessages ||
+              isCreatingConversation ||
+              isConversationBusy ||
+              isPastingAttachment
             }
-            onClick={() => void createConversation()}
+            onClick={handleCreateConversation}
           >
             <Plus className="h-4 w-4" aria-hidden="true" />
           </button>