fix: hide blank assistant message bubbles

desktop/src/components/chat/AssistantMessage.tsx

@@ -8,6 +8,8 @@ type Props = {
 }
 
 export function AssistantMessage({ content, isStreaming }: Props) {
+  if (!content.trim()) return null
+
   const documentLayout = shouldUseDocumentLayout(content)
 
   return (

desktop/src/components/chat/MessageList.test.tsx

@@ -95,6 +95,41 @@ describe('MessageList nested tool calls', () => {
     expect(container.textContent).toContain('Agent')
   })
 
+  it('does not render blank assistant bubbles for whitespace-only text', () => {
+    const messages: UIMessage[] = [
+      {
+        id: 'assistant-empty',
+        type: 'assistant_text',
+        content: '\n\n  ',
+        timestamp: 1,
+      },
+      {
+        id: 'tool-bash',
+        type: 'tool_use',
+        toolName: 'Bash',
+        toolUseId: 'bash-1',
+        input: { command: 'pwd' },
+        timestamp: 2,
+      },
+    ]
+
+    const { renderItems } = buildRenderModel(messages)
+    expect(renderItems).toHaveLength(1)
+    expect(renderItems[0]).toMatchObject({ kind: 'tool_group' })
+
+    useChatStore.setState({
+      sessions: {
+        [ACTIVE_TAB]: makeSessionState({
+          messages,
+          streamingText: '\n  ',
+        }),
+      },
+    })
+
+    const { container } = render(<MessageList />)
+    expect(container.querySelectorAll('[data-message-shell="assistant"]')).toHaveLength(0)
+  })
+
   it('keeps root tool runs split when nested child tool calls appear between them', () => {
     const messages: UIMessage[] = [
       {

desktop/src/components/chat/MessageList.tsx

@@ -90,6 +90,10 @@ export function buildRenderModel(messages: UIMessage[]): RenderModel {
   }
 
   for (const msg of messages) {
+    if (msg.type === 'assistant_text' && !msg.content.trim()) {
+      continue
+    }
+
     if (msg.type === 'tool_result' && toolUseIds.has(msg.toolUseId)) {
       continue
     }
@@ -495,7 +499,7 @@ export function MessageList({ sessionId, compact = false }: MessageListProps = {
           )
         })}
 
-        {streamingText && (
+        {streamingText.trim() && (
           <AssistantMessage content={streamingText} isStreaming={chatState === 'streaming'} />
         )}
 

desktop/src/stores/chatStore.test.ts

@@ -184,6 +184,35 @@ describe('chatStore history mapping', () => {
     ])
   })
 
+  it('skips whitespace-only assistant transcript messages', () => {
+    const messages: MessageEntry[] = [
+      {
+        id: 'assistant-empty',
+        type: 'assistant',
+        timestamp: '2026-04-06T00:00:00.000Z',
+        model: 'opus',
+        content: '\n\n  ',
+      },
+      {
+        id: 'assistant-real',
+        type: 'assistant',
+        timestamp: '2026-04-06T00:00:01.000Z',
+        model: 'opus',
+        content: '可见回复',
+      },
+    ]
+
+    const mapped = mapHistoryMessagesToUiMessages(messages)
+
+    expect(mapped).toMatchObject([
+      {
+        id: 'assistant-real',
+        type: 'assistant_text',
+        content: '可见回复',
+      },
+    ])
+  })
+
   it('surfaces teammate prompt content when mapping member transcript history', () => {
     const messages: MessageEntry[] = [
       {

desktop/src/stores/chatStore.ts

@@ -1080,6 +1080,7 @@ export function mapHistoryMessagesToUiMessages(
       continue
     }
     if (msg.type === 'assistant' && typeof msg.content === 'string') {
+      if (!msg.content.trim()) continue
       uiMessages.push({ id: msg.id || nextId(), type: 'assistant_text', content: msg.content, timestamp, model: msg.model })
       continue
     }