diff --git a/.gitignore b/.gitignore
index 050e891..b67e665 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,3 +30,4 @@ output
 .python-version
 pyproject.toml
 uv.lock
+node_modules
diff --git a/src/command/adapters/websocket.rs b/src/command/adapters/websocket.rs
index d6dd796..2b20022 100644
--- a/src/command/adapters/websocket.rs
+++ b/src/command/adapters/websocket.rs
@@ -77,6 +77,7 @@ impl OutputAdapter for WebSocketOutputAdapter {
                     id: response.request_id.to_string(),
                     content: msg.content.clone(),
                     role: "assistant".to_string(),
+                    attachments: Vec::new(),
                 },
                 MessageKind::Notification => {
                     // 根据元数据判断具体类型
@@ -96,6 +97,7 @@ impl OutputAdapter for WebSocketOutputAdapter {
                                 id: response.request_id.to_string(),
                                 content: msg.content.clone(),
                                 role: "assistant".to_string(),
+                                attachments: Vec::new(),
                             },
                         }
                     } else if let Some(session_id) = response.metadata.get("session_id") {
@@ -134,6 +136,7 @@ impl OutputAdapter for WebSocketOutputAdapter {
                                 id: response.request_id.to_string(),
                                 content: msg.content.clone(),
                                 role: "assistant".to_string(),
+                                attachments: Vec::new(),
                             },
                         }
                     } else if let Some(sessions_json) = response.metadata.get("sessions") {
@@ -151,6 +154,7 @@ impl OutputAdapter for WebSocketOutputAdapter {
                                 id: response.request_id.to_string(),
                                 content: msg.content.clone(),
                                 role: "assistant".to_string(),
+                                attachments: Vec::new(),
                             },
                         }
                     } else if let Some(topics_json) = response.metadata.get("topics") {
@@ -169,6 +173,7 @@ impl OutputAdapter for WebSocketOutputAdapter {
                                 id: response.request_id.to_string(),
                                 content: msg.content.clone(),
                                 role: "assistant".to_string(),
+                                attachments: Vec::new(),
                             },
                         }
                     } else {
@@ -177,6 +182,7 @@ impl OutputAdapter for WebSocketOutputAdapter {
                             id: response.request_id.to_string(),
                             content: msg.content.clone(),
                             role: "assistant".to_string(),
+                            attachments: Vec::new(),
                         }
                     }
                 }
@@ -188,6 +194,7 @@ impl OutputAdapter for WebSocketOutputAdapter {
                     id: response.request_id.to_string(),
                     content: msg.content.clone(),
                     role: "assistant".to_string(),
+                    attachments: Vec::new(),
                 },
             };
             outbounds.push(outbound);
diff --git a/src/gateway/session_message_sender.rs b/src/gateway/session_message_sender.rs
index 805b905..50cb569 100644
--- a/src/gateway/session_message_sender.rs
+++ b/src/gateway/session_message_sender.rs
@@ -33,6 +33,7 @@ impl SessionMessageSender for BusSessionMessageSender {
             .ok_or_else(|| anyhow::anyhow!("missing chat_id in tool context"))?;
 
         let metadata = HashMap::new();
+        let attachment_count = request.attachments.len();
         let mut published_messages = 0;
         let text_sent = request
             .text
@@ -43,47 +44,49 @@ impl SessionMessageSender for BusSessionMessageSender {
 
         if let Some(text) = request.text.filter(|value| !value.trim().is_empty()) {
             let content_len = text.len();
-            self.bus
-                .publish_outbound(OutboundMessage::assistant(
-                    channel_name.to_string(),
-                    chat_id.to_string(),
-                    None, // session_id
-                    text,
-                    None,
-                    metadata.clone(),
-                ))
-                .await?;
-            published_messages += 1;
-            tracing::info!(
-                channel = %channel_name,
-                chat_id = %chat_id,
-                content_len = content_len,
-                "Published session text message to outbound bus"
-            );
-        }
-
-        let attachment_count = request.attachments.len();
-        for attachment in request.attachments {
-            let media_path = attachment.path.clone();
-            let media_type = attachment.media_type.clone();
             let mut outbound = OutboundMessage::assistant(
                 channel_name.to_string(),
                 chat_id.to_string(),
                 None, // session_id
-                String::new(),
+                text,
                 None,
                 metadata.clone(),
             );
-            outbound.media = vec![attachment];
+            if attachment_count > 0 {
+                outbound.media = request.attachments.clone();
+            }
             self.bus.publish_outbound(outbound).await?;
             published_messages += 1;
             tracing::info!(
                 channel = %channel_name,
                 chat_id = %chat_id,
-                media_type = %media_type,
-                media_path = %media_path,
-                "Published session attachment to outbound bus"
+                content_len = content_len,
+                attachment_count = attachment_count,
+                "Published session text message to outbound bus"
             );
+        } else {
+            for attachment in request.attachments {
+                let media_path = attachment.path.clone();
+                let media_type = attachment.media_type.clone();
+                let mut outbound = OutboundMessage::assistant(
+                    channel_name.to_string(),
+                    chat_id.to_string(),
+                    None, // session_id
+                    String::new(),
+                    None,
+                    metadata.clone(),
+                );
+                outbound.media = vec![attachment];
+                self.bus.publish_outbound(outbound).await?;
+                published_messages += 1;
+                tracing::info!(
+                    channel = %channel_name,
+                    chat_id = %chat_id,
+                    media_type = %media_type,
+                    media_path = %media_path,
+                    "Published session attachment to outbound bus"
+                );
+            }
         }
 
         Ok(SessionSendOutcome {
@@ -129,19 +132,15 @@ mod tests {
         assert_eq!(
             outcome,
             SessionSendOutcome {
-                published_messages: 2,
+                published_messages: 1,
                 text_sent: true,
                 attachment_count: 1,
             }
         );
 
-        let first = bus.consume_outbound().await;
-        assert_eq!(first.content, "hello");
-        assert!(first.media.is_empty());
-
-        let second = bus.consume_outbound().await;
-        assert_eq!(second.content, "");
-        assert_eq!(second.media.len(), 1);
-        assert_eq!(second.media[0].media_type, "image");
+        let msg = bus.consume_outbound().await;
+        assert_eq!(msg.content, "hello");
+        assert_eq!(msg.media.len(), 1);
+        assert_eq!(msg.media[0].media_type, "image");
     }
 }
\ No newline at end of file
diff --git a/src/gateway/ws.rs b/src/gateway/ws.rs
index f235751..8a06364 100644
--- a/src/gateway/ws.rs
+++ b/src/gateway/ws.rs
@@ -355,10 +355,28 @@ async fn handle_inbound(
                     *current_topic_id = Some(topic_id.clone());
 
                     // 加载并发送该话题的历史消息
-                    if let Err(e) = send_topic_history(&store, topic_id, sender).await {
+                    if let Err(e) = send_topic_history(&store, current_session_id, topic_id, sender).await {
                         tracing::warn!(error = %e, topic_id = %topic_id, "Failed to send topic history");
                     }
                 }
+                if current_topic_id.is_none() {
+                    if let Some(topics_json) = response.metadata.get("topics") {
+                        match serde_json::from_str::<Vec<crate::protocol::TopicSummary>>(topics_json) {
+                            Ok(topics) => {
+                                if let Some(first_topic) = topics.first() {
+                                    let topic_id = first_topic.topic_id.clone();
+                                    *current_topic_id = Some(topic_id.clone());
+                                    if let Err(e) = send_topic_history(&store, current_session_id, &topic_id, sender).await {
+                                        tracing::warn!(error = %e, topic_id = %topic_id, "Failed to send initial topic history");
+                                    }
+                                }
+                            }
+                            Err(e) => {
+                                tracing::warn!(error = %e, "Failed to parse topics metadata for initial history");
+                            }
+                        }
+                    }
+                }
             } else if let Some(ref error) = response.error {
                 tracing::warn!(
                     error_code = %error.code,
@@ -400,11 +418,15 @@ fn resolve_ws_sender_id(sender_id: Option<&str>, runtime_session_id: &str) -> St
 /// 加载并发送话题历史消息
 async fn send_topic_history(
     store: &Arc<crate::storage::SessionStore>,
+    session_id: &str,
     topic_id: &str,
     sender: &mpsc::Sender<WsOutbound>,
 ) -> Result<(), Box<dyn std::error::Error>> {
     // 加载话题消息
-    let messages = store.load_messages_for_topic(topic_id)?;
+    let mut messages = store.load_messages_for_topic(topic_id)?;
+    if messages.is_empty() {
+        messages = store.load_messages(session_id)?;
+    }
 
     tracing::info!(topic_id = %topic_id, message_count = messages.len(), "Sending topic history");
 
@@ -443,6 +465,7 @@ fn chat_message_to_ws_outbound(msg: &crate::bus::ChatMessage) -> Option<WsOutbou
                 id: msg.id.clone(),
                 content: msg.content.clone(),
                 role: msg.role.clone(),
+                attachments: Vec::new(),
             })
         }
         "tool" => {
@@ -465,10 +488,12 @@ fn chat_message_to_ws_outbound(msg: &crate::bus::ChatMessage) -> Option<WsOutbou
                 }),
             }
         }
-        "user" => {
-            // 用户消息不通过 WsOutbound 发送，前端自己维护
-            None
-        }
+        "user" => Some(WsOutbound::AssistantResponse {
+            id: msg.id.clone(),
+            content: msg.content.clone(),
+            role: msg.role.clone(),
+            attachments: Vec::new(),
+        }),
         _ => None,
     }
 }
diff --git a/src/protocol/mod.rs b/src/protocol/mod.rs
index cada396..d23b7eb 100644
--- a/src/protocol/mod.rs
+++ b/src/protocol/mod.rs
@@ -34,6 +34,14 @@ pub struct TopicSummary {
     pub last_active_at: i64,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct MediaSummary {
+    pub path: String,
+    pub media_type: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub mime_type: Option<String>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(tag = "type")]
 pub enum WsInbound {
@@ -63,6 +71,8 @@ pub enum WsOutbound {
         id: String,
         content: String,
         role: String,
+        #[serde(default, skip_serializing_if = "Vec::is_empty")]
+        attachments: Vec<MediaSummary>,
     },
     #[serde(rename = "tool_call")]
     ToolCall {
diff --git a/src/protocol/ws_adapter.rs b/src/protocol/ws_adapter.rs
index 766829f..8513cf8 100644
--- a/src/protocol/ws_adapter.rs
+++ b/src/protocol/ws_adapter.rs
@@ -5,7 +5,7 @@ use crate::bus::message::OutboundEventKind;
 #[cfg(test)]
 use crate::bus::message::{ToolMessageState, format_tool_call_content};
 
-use super::WsOutbound;
+use super::{MediaSummary, WsOutbound};
 
 const TOOL_PENDING_RESUME_HINT: &str = "完成外部操作后，直接发一条继续消息即可。";
 
@@ -20,6 +20,7 @@ pub(crate) fn ws_outbound_from_chat_message(message: &ChatMessage) -> Vec<WsOutb
                         id: message.id.clone(),
                         content: message.content.clone(),
                         role: message.role.clone(),
+                        attachments: Vec::new(),
                     });
                 }
 
@@ -37,6 +38,7 @@ pub(crate) fn ws_outbound_from_chat_message(message: &ChatMessage) -> Vec<WsOutb
                     id: message.id.clone(),
                     content: message.content.clone(),
                     role: message.role.clone(),
+                    attachments: Vec::new(),
                 }]
             }
         }
@@ -68,10 +70,20 @@ pub(crate) fn ws_outbound_from_chat_message(message: &ChatMessage) -> Vec<WsOutb
 pub(crate) fn ws_outbound_from_outbound_message(message: &OutboundMessage) -> Vec<WsOutbound> {
     match message.event_kind {
         OutboundEventKind::AssistantResponse | OutboundEventKind::SchedulerNotification => {
+            let attachments: Vec<MediaSummary> = message
+                .media
+                .iter()
+                .map(|m| MediaSummary {
+                    path: m.path.clone(),
+                    media_type: m.media_type.clone(),
+                    mime_type: m.mime_type.clone(),
+                })
+                .collect();
             vec![WsOutbound::AssistantResponse {
                 id: uuid::Uuid::new_v4().to_string(),
                 content: message.content.clone(),
                 role: message.role.clone(),
+                attachments,
             }]
         }
         OutboundEventKind::ToolCall => vec![WsOutbound::ToolCall {
diff --git a/web/src/App.tsx b/web/src/App.tsx
index c78488d..035963c 100644
--- a/web/src/App.tsx
+++ b/web/src/App.tsx
@@ -1,4 +1,4 @@
-import { useCallback, useEffect } from 'react'
+import { useCallback, useEffect, useRef } from 'react'
 import { Zap, Cpu, MessageSquare } from 'lucide-react'
 import { ChatContainer } from './components/Chat/ChatContainer'
 import { TopicList } from './components/Sidebar/TopicList'
@@ -12,6 +12,8 @@ import type { Command } from './types/protocol'
 const WS_URL = 'ws://127.0.0.1:19876/ws'
 
 function App() {
+  const lastAutoSwitchedTopicRef = useRef<string | null>(null)
+
   const {
     // 连接状态
     connectionId,
@@ -64,6 +66,24 @@ function App() {
     }
   }, [sessionId, status, handleCommand, sendMessage, requestTopicList])
 
+  // Topics 加载后，自动选择第一个并通知后端切换，以便加载历史消息
+  useEffect(() => {
+    if (topics.length === 0 || status !== 'connected') {
+      return
+    }
+
+    const firstTopic = topics[0]
+    if (lastAutoSwitchedTopicRef.current === firstTopic.id) {
+      return
+    }
+
+    lastAutoSwitchedTopicRef.current = firstTopic.id
+    selectTopic(firstTopic.id)
+    const cmd = switchTopic(firstTopic.id)
+    handleCommand(cmd)
+    sendMessage({ type: 'command', payload: JSON.stringify(cmd) })
+  }, [topics, status, selectTopic, switchTopic, handleCommand, sendMessage]);
+
   const handleSendMessage = useCallback(
     (content: string) => {
       if (isReadOnly || !sessionId) {
@@ -136,6 +156,7 @@ function App() {
     [sendMessage, handleCommand, switchTopic, selectTopic]
   )
 
+  const chatMessages = messages.filter((message) => message.type !== 'tool_result')
   const toolMessages = messages
 
   return (
@@ -199,7 +220,7 @@ function App() {
         {/* Center - Chat */}
         <div className="flex-1 min-w-0 bg-[#0a0a0f]">
           <ChatContainer
-            messages={messages}
+            messages={chatMessages}
             isLoading={isLoading}
             isReadOnly={isReadOnly}
             channelName={session?.title ?? 'PicoBot'}
diff --git a/web/src/components/Chat/MessageBubble.tsx b/web/src/components/Chat/MessageBubble.tsx
index 13d5517..d93352b 100644
--- a/web/src/components/Chat/MessageBubble.tsx
+++ b/web/src/components/Chat/MessageBubble.tsx
@@ -1,12 +1,50 @@
-import { User, Bot, Wrench, CheckCircle, AlertCircle, Terminal } from 'lucide-react'
+import { User, Bot, Wrench, CheckCircle, AlertCircle, Terminal, File, Image, FileText, Music, Video, Download } from 'lucide-react'
 import ReactMarkdown from 'react-markdown'
 import remarkGfm from 'remark-gfm'
-import type { ChatMessage } from '../../types/protocol'
+import type { ChatMessage, Attachment } from '../../types/protocol'
 
 interface MessageBubbleProps {
   message: ChatMessage
 }
 
+function getAttachmentIcon(mediaType: string) {
+  switch (mediaType) {
+    case 'image': return <Image className="h-4 w-4" />
+    case 'audio': return <Music className="h-4 w-4" />
+    case 'video': return <Video className="h-4 w-4" />
+    case 'file': return <FileText className="h-4 w-4" />
+    default: return <File className="h-4 w-4" />
+  }
+}
+
+function getFileName(path: string): string {
+  const parts = path.replace(/\\/g, '/').split('/')
+  return parts[parts.length - 1] || path
+}
+
+function AttachmentCard({ attachment }: { attachment: Attachment }) {
+  const fileName = getFileName(attachment.path)
+  const downloadUrl = `/download?path=${encodeURIComponent(attachment.path)}`
+
+  return (
+    <a
+      href={downloadUrl}
+      download={fileName}
+      className="flex items-center gap-2 rounded-lg bg-white/5 border border-white/10 px-3 py-2 text-xs hover:bg-white/10 hover:border-[#00f0ff]/30 transition-colors cursor-pointer group"
+      title={`下载 ${fileName}`}
+    >
+      <span className="text-zinc-400 group-hover:text-[#00f0ff] transition-colors">
+        {getAttachmentIcon(attachment.media_type)}
+      </span>
+      <span className="text-zinc-300 truncate max-w-[200px] group-hover:text-white transition-colors" title={attachment.path}>
+        {fileName}
+      </span>
+      <span className="text-zinc-600 ml-auto shrink-0">{attachment.media_type}</span>
+      <Download className="h-3 w-3 text-zinc-600 group-hover:text-[#00f0ff] transition-colors" />
+    </a>
+  )
+}
+
 export function MessageBubble({ message }: MessageBubbleProps) {
   const isUser = message.role === 'user'
   const isTool = message.role === 'tool'
@@ -160,6 +198,13 @@ export function MessageBubble({ message }: MessageBubbleProps) {
               </ReactMarkdown>
             </div>
           )}
+          {message.attachments && message.attachments.length > 0 && (
+            <div className="mt-2 space-y-1">
+              {message.attachments.map((att: Attachment, idx: number) => (
+                <AttachmentCard key={idx} attachment={att} />
+              ))}
+            </div>
+          )}
         </div>
       </div>
     </div>
diff --git a/web/src/hooks/useChat.ts b/web/src/hooks/useChat.ts
index c9c8caa..c04fdb4 100644
--- a/web/src/hooks/useChat.ts
+++ b/web/src/hooks/useChat.ts
@@ -113,7 +113,6 @@ export function useChat(): UseChatReturn {
 
       case 'session_loaded': {
         setIsLoading(false)
-        setMessages([])
         break
       }
 
@@ -133,23 +132,22 @@ export function useChat(): UseChatReturn {
         setTopics(newTopics)
 
         // 默认选中第一个 Topic（如果没有选中）
-        if (newTopics.length > 0 && !selectedTopic) {
-          setSelectedTopic(newTopics[0].id)
-        }
         setIsLoading(false)
         break
       }
 
       case 'assistant_response': {
         const msg = message as AssistantResponse
+        const role = msg.role === 'user' || msg.role === 'tool' ? msg.role : 'assistant'
         setMessages((prev) => [
           ...prev,
           {
             id: msg.id,
-            role: 'assistant',
+            role,
             content: msg.content,
             timestamp: Date.now(),
             type: 'message',
+            attachments: msg.attachments,
           },
         ])
         setIsLoading(false)
@@ -225,7 +223,7 @@ export function useChat(): UseChatReturn {
         // 忽略这些消息
         break
     }
-  }, [selectedTopic])
+  }, [])
 
   const handleMessage = useCallback((content: string) => {
     setMessages((prev) => [
diff --git a/web/src/types/protocol.ts b/web/src/types/protocol.ts
index 63950c3..ed038fb 100644
--- a/web/src/types/protocol.ts
+++ b/web/src/types/protocol.ts
@@ -27,11 +27,18 @@ export type WsInbound = WsInboundMessage | WsInboundCommand | WsInboundPing
 // Outbound Messages (Server -> Client)
 // ============================================================================
 
+export interface Attachment {
+  path: string
+  media_type: string
+  mime_type?: string
+}
+
 export interface AssistantResponse {
   type: 'assistant_response'
   id: string
   content: string
   role: string
+  attachments?: Attachment[]
 }
 
 export interface ToolCall {
@@ -241,6 +248,7 @@ export interface ChatMessage {
   type?: 'message' | 'tool_call' | 'tool_result' | 'tool_pending'
   toolName?: string
   arguments?: unknown
+  attachments?: Attachment[]
 }
 
 export interface Topic {