diff --git a/dashboard/src/api/index.js b/dashboard/src/api/index.js
index 15f3a2e..777660e 100644
--- a/dashboard/src/api/index.js
+++ b/dashboard/src/api/index.js
@@ -218,6 +218,25 @@ export const roomsAPI = {
 }
 
 // ============ WebSocket ============
+
+/**
+ * Create a WebSocket connection for chat room
+ * 
+ * Event Types:
+ * - connected: Connection established
+ * - room_info: Room details with agents
+ * - history: Message history
+ * - agents: Agent list update
+ * - message: New message
+ * - typing: Typing indicator
+ * - stream_start: Streaming response started
+ * - stream_step: Streaming response chunk
+ * - stream_end: Streaming response completed
+ * - stream_error: Streaming error
+ * - system: System message (join/leave)
+ * - error: Generic error
+ * - pong: Heartbeat response
+ */
 export function createRoomWS(roomId, callbacks = {}) {
   const token = localStorage.getItem('access_token')
   const wsUrl = `${window.location.protocol === 'https:' ? 'wss:' : 'ws:'}//${window.location.host}/ws/chat-room/${roomId}${token ? '?token=' + token : ''}`
@@ -233,31 +252,76 @@ export function createRoomWS(roomId, callbacks = {}) {
     try {
       const msg = JSON.parse(event.data)
       const eventName = msg.event
+      const data = msg.data || {}
 
       switch (eventName) {
+        // Connection events
         case 'connected':
-          callbacks.onConnected?.(msg.data)
+          callbacks.onConnected?.(data)
           break
+          
+        case 'room_info':
+          callbacks.onRoomInfo?.(data.room)
+          break
+          
+        // History and messages
         case 'history':
-          callbacks.onHistory?.(msg.data.messages)
-          break
-        case 'agents':
-          callbacks.onAgentsUpdate?.(msg.data.agents)
+          callbacks.onHistory?.(data.messages, data.has_more)
           break
+          
         case 'message':
-          callbacks.onMessage?.(msg.data)
+          // New message received
+          callbacks.onMessage?.(data.message)
           break
+          
+        // Agent events
+        case 'agents':
+          callbacks.onAgentsUpdate?.(data.agents, data.count)
+          break
+          
+        // Typing indicator
         case 'typing':
-          callbacks.onTyping?.(msg.data)
+          callbacks.onTyping?.({
+            sender_id: data.sender_id,
+            sender_type: data.sender_type,
+            agent_name: data.agent_name,
+            is_typing: data.is_typing
+          })
           break
+          
+        // Streaming events (new format)
+        case 'stream_start':
+          callbacks.onStreamStart?.(data)
+          break
+          
+        case 'stream_step':
+          callbacks.onStreamStep?.(data)
+          break
+          
+        case 'stream_end':
+          callbacks.onStreamEnd?.(data)
+          break
+          
+        case 'stream_error':
+          callbacks.onStreamError?.(data)
+          break
+          
+        // Legacy streaming events (for backward compatibility)
         case 'process_step':
         case 'done':
         case 'error':
-          callbacks.onStream?.(eventName, msg.data, msg.agent_id, msg.agent_name)
+          callbacks.onStream?.(eventName, data, data.agent_id, data.agent_name)
           break
+          
+        // System events
         case 'system':
-          callbacks.onSystem?.(msg.data)
+          callbacks.onSystem?.(data)
           break
+          
+        case 'pong':
+          callbacks.onPong?.()
+          break
+          
         default:
           console.log('Unknown event:', eventName, msg)
       }
@@ -282,24 +346,34 @@ export function createRoomWS(roomId, callbacks = {}) {
         ws.send(JSON.stringify({ action, ...data }))
       }
     },
-    sendMessage: (content, userId = 'user', userName = 'User') => {
+    
+    sendMessage: (content, userId = 'user', userName = 'User', options = {}) => {
+      const payload = { 
+        action: 'send_message', 
+        content, 
+        user_id: userId, 
+        user_name: userName,
+        ...options  // Support: reply_to, mentions
+      }
+      
       const send = () => {
         if (ws.readyState === WebSocket.OPEN) {
-          ws.send(JSON.stringify({ action: 'send_message', content, user_id: userId, user_name: userName }))
+          ws.send(JSON.stringify(payload))
         } else if (ws.readyState === WebSocket.CONNECTING) {
-          // Wait for connection then retry
           ws.addEventListener('open', () => {
-            ws.send(JSON.stringify({ action: 'send_message', content, user_id: userId, user_name: userName }))
+            ws.send(JSON.stringify(payload))
           }, { once: true })
         }
       }
       send()
     },
+    
     ping: () => {
       if (ws.readyState === WebSocket.OPEN) {
         ws.send(JSON.stringify({ action: 'ping' }))
       }
     },
+    
     close: () => ws.close()
   }
 }
diff --git a/dashboard/src/components/ListItem.vue b/dashboard/src/components/ListItem.vue
index 9b24061..7b1b86c 100644
--- a/dashboard/src/components/ListItem.vue
+++ b/dashboard/src/components/ListItem.vue
@@ -17,13 +17,13 @@
     <!-- 操作按钮 -->
     <div class="item-actions">
       <slot name="actions">
-        <button v-if="onEdit" @click.stop="$emit('edit')" class="btn-icon" title="编辑">
+        <button v-if="showEdit" @click.stop="$emit('edit')" class="btn-icon" title="编辑">
           <svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
             <path d="M11 4H4a2 2 0 0 0-2 2v14a2 2 0 0 0 2 2h14a2 2 0 0 0 2-2v-7"></path>
             <path d="M18.5 2.5a2.121 2.121 0 0 1 3 3L12 15l-4 1 1-4 9.5-9.5z"></path>
           </svg>
         </button>
-        <button v-if="onDelete" @click.stop="$emit('delete')" class="btn-icon btn-delete-icon" title="删除">
+        <button v-if="showDelete" @click.stop="$emit('delete')" class="btn-icon btn-delete-icon" title="删除">
           <svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
             <polyline points="3 6 5 6 21 6"></polyline>
             <path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"></path>
@@ -45,8 +45,8 @@ const props = defineProps({
   avatarColor: { type: String, default: '#667eea' },
   active: { type: Boolean, default: false },
   inRoom: { type: Boolean, default: false },
-  onEdit: { type: Boolean, default: true },
-  onDelete: { type: Boolean, default: true },
+  showEdit: { type: Boolean, default: true },
+  showDelete: { type: Boolean, default: true },
 })
 
 defineEmits(['click', 'edit', 'delete'])
diff --git a/dashboard/src/components/MessageBubble.vue b/dashboard/src/components/MessageBubble.vue
index f6f19d9..b2ec62d 100644
--- a/dashboard/src/components/MessageBubble.vue
+++ b/dashboard/src/components/MessageBubble.vue
@@ -1,7 +1,7 @@
 <template>
-  <div class="message-bubble" :class="[message.role]">
-    <div v-if="message.role === 'user'" class="avatar">user</div>
-    <div v-else class="avatar">Luxx</div>
+  <div class="message-bubble" :class="[messageType]">
+    <div v-if="isUser" class="avatar">user</div>
+    <div v-else class="avatar">{{ senderName }}</div>
     <div class="message-container">
       <!-- File attachments list -->
       <div v-if="message.attachments && message.attachments.length > 0" class="attachments-list">
@@ -27,18 +27,18 @@
       </div>
       <div class="message-footer">
         <span class="message-time">{{ formatTime(message.created_at) }}</span>
-        <template v-if="message.role === 'assistant' && message.usage">
+        <template v-if="isAssistant && message.usage">
           <span class="token-item" v-if="message.usage.prompt">{{ formatNumber(message.usage.prompt) }} in</span>
           <span class="token-item" v-if="message.usage.completion">{{ formatNumber(message.usage.completion) }} out</span>
           <span class="token-item" v-if="message.usage.total">{{ formatNumber(message.usage.total) }} total</span>
         </template>
-        <button v-if="message.role === 'assistant'" class="ghost-btn success" @click="$emit('regenerate', message.id)" title="重新生成">
+        <button v-if="isAssistant" class="ghost-btn success" @click="$emit('regenerate', message.id)" title="重新生成">
           <span v-html="regenerateIcon"></span>
         </button>
-        <button v-if="message.role === 'assistant'" class="ghost-btn accent" @click="copyContent" title="复制">
+        <button v-if="isAssistant" class="ghost-btn accent" @click="copyContent" title="复制">
           <span v-html="copyIcon"></span>
         </button>
-        <button v-if="deletable" class="ghost-btn danger" @click="$emit('delete', message.id)" title="删除">
+        <button v-if="deletable && isUser" class="ghost-btn danger" @click="$emit('delete', message.id)" title="删除">
           <span v-html="trashIcon"></span>
         </button>
       </div>
@@ -55,12 +55,21 @@ import ProcessBlock from './ProcessBlock.vue'
 const props = defineProps({
   message: { type: Object, required: true },
   deletable: { type: Boolean, default: false },
+  senderName: { type: String, default: 'Luxx' }, // 可配置的发送者名称
 })
 
 defineEmits(['delete', 'regenerate'])
 
 const messageRef = ref(null)
 
+// 支持 sender_type (Room 场景) 和 role (Conversation 场景)
+const messageType = computed(() => {
+  return props.message.sender_type || props.message.role || 'assistant'
+})
+
+const isUser = computed(() => messageType.value === 'user')
+const isAssistant = computed(() => messageType.value === 'assistant' || messageType.value === 'agent')
+
 const renderedContent = computed(() => {
   const text = props.message.content || props.message.text || ''
   if (!text) return ''
diff --git a/dashboard/src/views/RoomView.vue b/dashboard/src/views/RoomView.vue
index 5c83e78..ed5558d 100644
--- a/dashboard/src/views/RoomView.vue
+++ b/dashboard/src/views/RoomView.vue
@@ -136,9 +136,10 @@
 
         <!-- 消息列表 -->
         <div class="messages-container" ref="messagesContainer">
-          <RoomMessageBubble
+          <MessageBubble
             v-for="msg in messages" :key="msg.id"
             :message="msg"
+            :sender-name="msg.sender_name || 'Luxx'"
           />
 
           <!-- 正在输入的流式消息 -->
@@ -149,10 +150,15 @@
             </div>
             <div class="message-container">
               <div class="message-body">
-                <div class="md-content" v-html="renderMarkdown(stream.content)"></div>
+                <ProcessBlock
+                  v-if="stream.process_steps && stream.process_steps.length > 0"
+                  :process-steps="stream.process_steps"
+                  :streaming="true"
+                />
+                <div v-else class="md-content" v-html="renderMarkdown(stream.content)"></div>
               </div>
               <div class="message-footer">
-                <span class="sender-name">{{ stream.agentName }}</span>
+                <span class="message-time">{{ stream.agentName }}</span>
                 <span class="typing-indicator">正在输入...</span>
               </div>
             </div>
@@ -304,7 +310,8 @@ import { roomsAPI, createRoomWS, agentsAPI, providersAPI } from '@/api'
 import { marked } from 'marked'
 import ListItem from '@/components/ListItem.vue'
 import InlineForm from '@/components/InlineForm.vue'
-import RoomMessageBubble from '@/components/RoomMessageBubble.vue'
+import MessageBubble from '@/components/MessageBubble.vue'
+import ProcessBlock from '@/components/ProcessBlock.vue'
 
 const rooms = ref([])
 const currentRoom = ref(null)
@@ -321,11 +328,15 @@ const editingRoom = ref(null)
 const editingAgent = ref(null)
 
 const showAddMembers = ref(false)
+const showCreateRoom = ref(false)
+const showRoomManage = ref(false)
+const roomTab = ref('list')
 const inputMessage = ref('')
 const messagesContainer = ref(null)
 let ws = null
 
 const roomForm = reactive({ name: '', description: '' })
+const newRoom = reactive({ name: '', description: '' })
 
 const agentForm = reactive({
   name: '',
@@ -398,6 +409,43 @@ function closeRoomForm() {
   Object.assign(roomForm, { name: '', description: '' })
 }
 
+async function createRoom() {
+  try {
+    const res = await roomsAPI.create(newRoom)
+    rooms.value.push(res.room)
+    showCreateRoom.value = false
+    Object.assign(newRoom, { name: '', description: '' })
+    joinRoom(res.room)
+  } catch (e) {
+    console.error('Failed to create room:', e)
+    alert('创建失败')
+  }
+}
+
+function editRoom(room) {
+  editingRoom.value = room
+  Object.assign(roomForm, { name: room.name, description: room.description || '' })
+  roomTab.value = 'edit'
+}
+
+async function deleteRoom(roomId) {
+  if (!confirm('确定删除此聊天室？')) return
+  try {
+    await roomsAPI.delete(roomId)
+    rooms.value = rooms.value.filter(r => r.id !== roomId)
+    if (currentRoom.value?.id === roomId) {
+      currentRoom.value = null
+      messages.value = []
+    }
+    if (roomTab.value === 'list') {
+      // Refresh room list in modal
+    }
+  } catch (e) {
+    console.error('Failed to delete room:', e)
+    alert('删除失败')
+  }
+}
+
 async function saveRoom() {
   try {
     if (editingRoom.value) {
@@ -445,39 +493,113 @@ async function joinRoom(room) {
   streamingMessages.value = {}
   typingAgents.value = new Set()
 
-  // 加载房间成员
-  try {
-    const res = await roomsAPI.listAgents(room.id)
-    roomAgents.value = res.agents || []
-  } catch (e) {
-    console.error('Failed to load room agents:', e)
-    roomAgents.value = []
-  }
-
-  // WebSocket 连接
+  // WebSocket 连接 - 使用新的事件格式
   ws = createRoomWS(room.id, {
-    onConnected: () => console.log('Connected to room'),
-    onHistory: (msgs) => {
+    onConnect: () => console.log('Connecting to room...'),
+    
+    onConnected: (data) => {
+      console.log('Connected to room:', data)
+    },
+    
+    onRoomInfo: (roomData) => {
+      currentRoom.value = roomData
+    },
+    
+    onHistory: (msgs, hasMore) => {
+      // 新格式: messages 直接是数组
       messages.value = msgs || []
       scrollToBottom()
     },
-    onAgentsUpdate: (agents) => {
+    
+    onAgentsUpdate: (agents, count) => {
+      // 新格式: agents 是对象数组
       roomAgents.value = agents || []
     },
+    
     onMessage: (msg) => {
-      messages.value.push(msg)
+      // 新格式: msg 是 { message: {...} } 结构，需要提取 message
+      const message = msg.message || msg
+      messages.value.push(message)
       scrollToBottom()
     },
+    
     onTyping: (data) => {
+      // 新格式: {sender_id, sender_type, agent_name, is_typing}
       if (data.is_typing) {
-        typingAgents.value.add(data.agent_id)
+        typingAgents.value.add(data.sender_id)
       } else {
-        typingAgents.value.delete(data.agent_id)
+        typingAgents.value.delete(data.sender_id)
       }
     },
+    
+    // 新的流式响应处理
+    onStreamStart: (data) => {
+      // {stream_id, message_id, agent, parent_message_id}
+      const agentId = data.agent?.id
+      const agentName = data.agent?.name || 'Agent'
+      streamingMessages.value[agentId] = {
+        streamId: data.stream_id,
+        agentName,
+        content: '',
+        steps: []
+      }
+      typingAgents.value.add(agentId)
+    },
+    
+    onStreamStep: (data) => {
+      // {stream_id, step: {id, type, delta, full, done}}
+      const streamData = streamingMessages.value[data.stream_id] || streamingMessages.value[Object.keys(streamingMessages.value)[0]]
+      if (!streamData) return
+      
+      const step = data.step
+      if (step.type === 'text' || step.type === 'thinking') {
+        streamData.content = step.full
+      }
+      if (step.arguments !== undefined) {
+        // Tool call step
+        if (!streamData.toolCalls) streamData.toolCalls = []
+        streamData.toolCalls.push(step)
+      }
+    },
+    
+    onStreamEnd: (data) => {
+      // {stream_id, content, token_count, usage}
+      const agentId = Object.keys(streamingMessages.value).find(
+        key => streamingMessages.value[key].streamId === data.stream_id
+      )
+      
+      if (agentId && streamingMessages.value[agentId]) {
+        const streamData = streamingMessages.value[agentId]
+        messages.value.push({
+          id: `msg-${Date.now()}`,
+          sender_type: 'agent',
+          sender_id: agentId,
+          sender_name: streamData.agentName,
+          content: data.content || streamData.content,
+          token_count: data.token_count,
+          created_at: new Date().toISOString()
+        })
+        delete streamingMessages.value[agentId]
+      }
+      typingAgents.value.delete(agentId)
+      scrollToBottom()
+    },
+    
+    onStreamError: (data) => {
+      // {stream_id, error}
+      console.error('Stream error:', data.error)
+      const agentId = Object.keys(streamingMessages.value).find(
+        key => streamingMessages.value[key].streamId === data.stream_id
+      )
+      if (agentId) {
+        delete streamingMessages.value[agentId]
+        typingAgents.value.delete(agentId)
+      }
+    },
+    
+    // 兼容旧的流式格式
     onStream: (event, data, agentId, agentName) => {
       if (event === 'process_step') {
-        // data.step contains {id, index, type, content}
         const step = data.step || data
         if (!streamingMessages.value[agentId]) {
           streamingMessages.value[agentId] = { agentName, content: '' }
@@ -486,7 +608,6 @@ async function joinRoom(room) {
           streamingMessages.value[agentId].content = step.content
         }
       } else if (event === 'done') {
-        // Save streaming message to messages list before removing
         if (streamingMessages.value[agentId]) {
           messages.value.push({
             id: `msg-${Date.now()}`,
@@ -501,8 +622,16 @@ async function joinRoom(room) {
         typingAgents.value.delete(agentId)
       }
     },
+    
     onSystem: (data) => {
-      console.log('System:', data)
+      // {type, sender, content, message}
+      console.log('System event:', data)
+      if (data.message) {
+        // 提取 message 对象
+        const message = data.message.message || data.message
+        messages.value.push(message)
+        scrollToBottom()
+      }
     }
   })
 }
diff --git a/luxx/api/rooms.py b/luxx/api/rooms.py
index 062a68a..fb9cf42 100644
--- a/luxx/api/rooms.py
+++ b/luxx/api/rooms.py
@@ -22,6 +22,8 @@ class UpdateChatRoomRequest(BaseModel):
 
 class SendMessageRequest(BaseModel):
     content: str
+    reply_to: Optional[str] = None  # Message ID to reply to
+    mentions: Optional[List[str]] = None  # Mentioned agent IDs
 
 
 class AddAgentRequest(BaseModel):
@@ -56,7 +58,7 @@ async def create_chat_room(request: CreateChatRoomRequest):
 
 @router.get("/{room_id}")
 async def get_chat_room(room_id: str):
-    """Get a chat room by ID"""
+    """Get a chat room by ID with agents"""
     room = chat_room_service.get_room(room_id)
     if not room:
         raise HTTPException(status_code=404, detail="Chat room not found")
@@ -79,7 +81,7 @@ async def update_chat_room(room_id: str, request: UpdateChatRoomRequest):
 
 @router.delete("/{room_id}")
 async def delete_chat_room(room_id: str):
-    """Delete a chat room"""
+    """Delete a chat room and all related data"""
     success = chat_room_service.delete_room(room_id)
     if not success:
         raise HTTPException(status_code=404, detail="Chat room not found")
@@ -88,9 +90,23 @@ async def delete_chat_room(room_id: str):
 
 @router.get("/{room_id}/agents")
 async def get_room_agents(room_id: str):
-    """Get all agents in a chat room"""
+    """Get all agents in a chat room (from stable RoomAgent table)"""
+    # Return both BaseAgent objects and info from RoomAgent table
     agents = chat_room_service.get_room_agents(room_id)
-    return {"agents": [a.to_dict() for a in agents]}
+    agents_info = chat_room_service.get_room_agents_info(room_id)
+    
+    # Merge agent data
+    agent_data = []
+    for agent in agents:
+        agent_dict = agent.to_dict()
+        # Find matching info
+        for info in agents_info:
+            if info.get("id") == agent.agent_id:
+                agent_dict.update(info)
+                break
+        agent_data.append(agent_dict)
+    
+    return {"agents": agent_data, "count": len(agent_data)}
 
 
 @router.post("/{room_id}/agents")
@@ -99,7 +115,9 @@ async def add_agent_to_room(room_id: str, request: AddAgentRequest):
     success = chat_room_service.add_agent_to_room(room_id, request.agent_id)
     if not success:
         raise HTTPException(status_code=400, detail="Failed to add agent")
-    return {"success": True}
+    # Return updated agents list
+    agents = chat_room_service.get_room_agents_info(room_id)
+    return {"success": True, "agents": agents}
 
 
 @router.delete("/{room_id}/agents/{agent_id}")
@@ -115,12 +133,15 @@ async def remove_agent_from_room(room_id: str, agent_id: str):
 async def get_room_messages(room_id: str, limit: int = 50, before_id: str = None):
     """Get messages from a chat room"""
     messages = chat_room_service.get_messages(room_id, limit=limit, before_id=before_id)
-    return {"messages": messages}
+    return {"messages": messages, "count": len(messages)}
 
 
 @router.post("/{room_id}/messages")
 async def send_message(room_id: str, request: SendMessageRequest):
-    """Send a message to a chat room. Returns a streaming response via SSE."""
+    """Send a message to a chat room. Returns a streaming response via SSE.
+    
+    This endpoint is for HTTP-based messaging. WebSocket is preferred for real-time chat.
+    """
     from fastapi.responses import StreamingResponse
     import json
 
@@ -128,21 +149,27 @@ async def send_message(room_id: str, request: SendMessageRequest):
     user_name = "User"
 
     async def generate():
+        # Save user message first
+        user_msg = chat_room_service.save_message(
+            room_id=room_id,
+            sender_type="user",
+            sender_name=user_name,
+            content=request.content,
+            sender_id=user_id,
+            mentions=request.mentions,
+            parent_id=request.reply_to
+        )
+        
+        # Yield saved message event
+        yield f"data: {json.dumps({'event': 'message', 'data': {'message': user_msg}}, ensure_ascii=False)}\n\n"
+        
+        # Process and stream agent responses
         async for event in chat_room_service.process_message(
             room_id=room_id,
             user_message=request.content,
-            user_id=user_id,
-            user_name=user_name
+            sender_id=user_id,
+            sender_name=user_name
         ):
-            if event.get("event") in ["process_step", "done"]:
-                chat_room_service.save_message(
-                    room_id=room_id,
-                    sender_type="user",
-                    sender_id=user_id,
-                    sender_name=user_name,
-                    content=request.content
-                )
-
             yield f"data: {json.dumps(event, ensure_ascii=False)}\n\n"
 
     return StreamingResponse(
diff --git a/luxx/models/__init__.py b/luxx/models/__init__.py
index 838d782..8bd7bb3 100644
--- a/luxx/models/__init__.py
+++ b/luxx/models/__init__.py
@@ -1,12 +1,12 @@
 """Models package"""
 from luxx.models.user import User, LLMProvider, Project
 from luxx.models.chat import Conversation, Message
-from luxx.models.room import ChatRoom, Agent
+from luxx.models.room import ChatRoom, Agent, RoomAgent
 from luxx.models.participant import Participant, ParticipantType
 
 __all__ = [
     "User", "LLMProvider", "Project",
     "Conversation", "Message",
-    "ChatRoom", "Agent",
+    "ChatRoom", "Agent", "RoomAgent",
     "Participant", "ParticipantType",
 ]
diff --git a/luxx/models/chat.py b/luxx/models/chat.py
index e006ee4..261dedb 100644
--- a/luxx/models/chat.py
+++ b/luxx/models/chat.py
@@ -57,18 +57,35 @@ class Conversation(Base):
 
 class Message(Base):
     """Unified Message model for Conversation and ChatRoom.
-
-    role: user/assistant/system/tool
-    content: JSON format with text, attachments, tool_calls, steps
+    
+    统一消息模型，支持:
+    - Conversation: 单人会话
+    - ChatRoom: 聊天室（多 Agent）
+    
+    sender_type: user | agent | system
+    content: JSON 格式 {"text": "...", "steps": [...]}
     """
     __tablename__ = "messages"
 
     id: Mapped[str] = mapped_column(String(64), primary_key=True)
     conversation_id: Mapped[Optional[str]] = mapped_column(String(64), ForeignKey("conversations.id"), nullable=True)
     room_id: Mapped[Optional[str]] = mapped_column(String(64), nullable=True)
-    role: Mapped[str] = mapped_column(String(16), nullable=False)
-    content: Mapped[str] = mapped_column(Text, nullable=False, default="")
+    
+    # 发送者信息
+    sender_id: Mapped[str] = mapped_column(String(64), nullable=False, default="")      # 用户ID 或 AgentID
+    sender_type: Mapped[str] = mapped_column(String(16), nullable=False, default="user")  # "user" | "agent" | "system"
     sender_name: Mapped[str] = mapped_column(String(50), nullable=False, default="")
+    
+    # 消息内容（兼容旧格式，同时保留 role 字段用于兼容 Conversation）
+    role: Mapped[str] = mapped_column(String(16), nullable=False, default="user")  # 保留，兼容 Conversation
+    content: Mapped[str] = mapped_column(Text, nullable=False, default="")
+    
+    # 流式响应元数据
+    is_streaming: Mapped[bool] = mapped_column(Boolean, default=False)
+    stream_id: Mapped[Optional[str]] = mapped_column(String(64), nullable=True)
+    parent_id: Mapped[Optional[str]] = mapped_column(String(64), nullable=True)  # 回复的消息ID
+    
+    # 元数据
     mentions: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
     token_count: Mapped[int] = mapped_column(Integer, default=0)
     usage: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
@@ -84,18 +101,36 @@ class Message(Base):
     def target_id(self) -> str:
         return self.conversation_id or self.room_id or ""
 
-    def to_dict(self):
+    def to_dict(self, include_stream_data: bool = False):
+        """转换消息为字典
+        
+        统一使用 sender 格式，content 保留 JSON 和纯文本两种格式
+        """
         result = {
             "id": self.id,
             "conversation_id": self.conversation_id,
             "room_id": self.room_id,
             "target_type": self.target_type,
             "target_id": self.target_id,
-            "role": self.role,
+            "sender": {
+                "id": self.sender_id,
+                "type": self.sender_type,
+                "name": self.sender_name
+            },
+            # 兼容字段
+            "sender_id": self.sender_id,
+            "sender_type": self.sender_type,
             "sender_name": self.sender_name,
+            "role": self.role,  # 保留，兼容 Conversation
             "token_count": self.token_count,
+            "is_streaming": self.is_streaming,
             "created_at": self.created_at.isoformat() if self.created_at else None
         }
+        
+        # 流式数据
+        if include_stream_data:
+            result["stream_id"] = self.stream_id
+            result["parent_id"] = self.parent_id
 
         # Parse usage JSON
         if self.usage:
@@ -113,22 +148,20 @@ class Message(Base):
         else:
             result["mentions"] = []
 
-        # Parse content JSON
+        # Parse content JSON - 提取 text 和 steps
         try:
             content_obj = json.loads(self.content) if self.content else {}
+            result["content"] = content_obj.get("text", content_obj.get("content", self.content))
+            result["text"] = result["content"]
+            result["process_steps"] = content_obj.get("steps", content_obj.get("process_steps", []))
+            result["attachments"] = content_obj.get("attachments", [])
+            result["tool_calls"] = content_obj.get("tool_calls", [])
         except json.JSONDecodeError:
+            # 纯文本内容
             result["text"] = self.content
+            result["content"] = self.content
+            result["process_steps"] = []
             result["attachments"] = []
             result["tool_calls"] = []
-            result["process_steps"] = []
-            return result
-
-        result["text"] = content_obj.get("text", "")
-        result["attachments"] = content_obj.get("attachments", [])
-        result["tool_calls"] = content_obj.get("tool_calls", [])
-        result["process_steps"] = content_obj.get("steps", [])
-
-        if "content" not in content_obj:
-            result["content"] = result["text"]
 
         return result
diff --git a/luxx/models/room.py b/luxx/models/room.py
index e07b28e..6105cff 100644
--- a/luxx/models/room.py
+++ b/luxx/models/room.py
@@ -1,7 +1,7 @@
 """ChatRoom models - unified participant architecture"""
 from datetime import datetime
 from typing import Optional, List, TYPE_CHECKING
-from sqlalchemy import String, Integer, Boolean, Text, DateTime, ForeignKey
+from sqlalchemy import String, Integer, Boolean, Text, DateTime, ForeignKey, UniqueConstraint
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from luxx.core.database import Base
@@ -27,14 +27,44 @@ class ChatRoom(Base):
     updated_at: Mapped[datetime] = mapped_column(DateTime, default=local_now, onupdate=local_now)
 
     owner: Mapped["User"] = relationship("User", backref="chat_rooms")
+    room_agents: Mapped[List["RoomAgent"]] = relationship("RoomAgent", back_populates="room", cascade="all, delete-orphan")
 
-    def to_dict(self):
-        return {
+    def to_dict(self, include_agents: bool = False):
+        result = {
             "id": self.id, "name": self.name, "description": self.description,
             "owner_id": self.owner_id, "is_active": self.is_active,
             "created_at": self.created_at.isoformat() if self.created_at else None,
             "updated_at": self.updated_at.isoformat() if self.updated_at else None
         }
+        if include_agents:
+            result["agents"] = [ra.to_dict() for ra in self.room_agents]
+        return result
+
+
+class RoomAgent(Base):
+    """ChatRoom 与 Agent 的关联表（替代依赖 Message 表的不稳定方案）"""
+    __tablename__ = "room_agents"
+    __table_args__ = (
+        UniqueConstraint('room_id', 'agent_id', name='uq_room_agent'),
+    )
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    room_id: Mapped[str] = mapped_column(String(64), ForeignKey("chat_rooms.id", ondelete="CASCADE"), nullable=False)
+    agent_id: Mapped[str] = mapped_column(String(64), ForeignKey("agents.id", ondelete="CASCADE"), nullable=False)
+    joined_at: Mapped[datetime] = mapped_column(DateTime, default=local_now)
+    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
+
+    room: Mapped["ChatRoom"] = relationship("ChatRoom", back_populates="room_agents")
+    agent: Mapped["Agent"] = relationship("Agent")
+
+    def to_dict(self):
+        return {
+            "id": self.agent_id,
+            "room_agent_id": self.id,
+            "joined_at": self.joined_at.isoformat() if self.joined_at else None,
+            "is_active": self.is_active,
+            "agent": self.agent.to_dict() if self.agent else None
+        }
 
 
 class Agent(Base):
diff --git a/luxx/services/participant.py b/luxx/services/participant.py
index d5a526a..e26733a 100644
--- a/luxx/services/participant.py
+++ b/luxx/services/participant.py
@@ -1,6 +1,6 @@
 """Participant Service - unified service for users and agents in chat rooms."""
 import logging
-from typing import Dict, Any, Optional, AsyncGenerator
+from typing import Dict, Any, Optional, AsyncGenerator, List
 
 from luxx.agents.base import BaseAgent
 from luxx.agents.registry import agent_registry
@@ -25,11 +25,11 @@ class ParticipantService:
     # ==================== Agent ====================
 
     def register_agent(self, agent: BaseAgent) -> Participant:
+        """Register an active agent in the participant service"""
         self._active_agents[agent.agent_id] = agent
         agent_registry.register(agent)
         return Participant.from_agent(
-            agent.agent_id, agent.name, agent.role, agent.avatar,
-            agent.auto_response, agent.mention_trigger, agent.priority
+            agent.agent_id, agent.name, agent.role, agent.avatar
         )
 
     def unregister_agent(self, agent_id: str) -> bool:
@@ -40,13 +40,13 @@ class ParticipantService:
         return False
 
     def get_agent_participant(self, agent_id: str) -> Optional[Participant]:
+        """Get agent participant info"""
         agent = self._active_agents.get(agent_id) or chat_room_service.get_agent(agent_id)
         if agent:
             if agent_id not in self._active_agents:
                 self._active_agents[agent_id] = agent
             return Participant.from_agent(
-                agent.agent_id, agent.name, agent.role, agent.avatar,
-                agent.auto_response, agent.mention_trigger, agent.priority
+                agent.agent_id, agent.name, agent.role, agent.avatar
             )
         return None
 
@@ -86,42 +86,76 @@ class ParticipantService:
         self, room_id: str, content: str, sender_id: str,
         sender_name: str, sender_type: str = "user", context: Dict = None
     ) -> AsyncGenerator[Dict[str, Any], None]:
+        """Process a message in a chat room
+        
+        This is a wrapper around chat_room_service.process_message
+        that handles broadcasting and typing indicators.
+        """
         cm = self._cm()
 
-        msg = chat_room_service.save_message(room_id, sender_type, sender_id, sender_name, content)
-        await cm.broadcast_to_room(room_id, {"event": "message", "data": msg})
+        # Save and broadcast message
+        msg = chat_room_service.save_message(
+            room_id=room_id,
+            sender_type=sender_type,
+            sender_name=sender_name,
+            content=content,
+            sender_id=str(sender_id)
+        )
+        await cm.broadcast_to_room(room_id, {"event": "message", "data": {"message": msg}})
 
+        # Get room agents
         room_agents = chat_room_service.get_room_agents(room_id)
         if sender_type == "agent":
             room_agents = [a for a in room_agents if a.agent_id != sender_id]
 
+        # Broadcast typing indicators
         for agent in room_agents:
             await cm.broadcast_to_room(room_id, {
                 "event": "typing",
-                "data": {"agent_id": agent.agent_id, "agent_name": agent.name, "is_typing": True}
+                "data": {
+                    "sender_id": agent.agent_id,
+                    "sender_type": "agent",
+                    "agent_name": agent.name,
+                    "is_typing": True
+                }
             })
 
+        # Process and yield events
         ctx = (context or {})
         ctx.update({"sender_type": sender_type, "sender_id": sender_id, "username": sender_name})
 
         async for event in chat_room_service.process_message(room_id, content, sender_id, sender_name, ctx):
             yield event
 
+        # Clear typing indicators
         for agent in room_agents:
             await cm.broadcast_to_room(room_id, {
                 "event": "typing",
-                "data": {"agent_id": agent.agent_id, "agent_name": agent.name, "is_typing": False}
+                "data": {
+                    "sender_id": agent.agent_id,
+                    "sender_type": "agent",
+                    "agent_name": agent.name,
+                    "is_typing": False
+                }
             })
 
     async def send_message(
         self, room_id: str, participant_id: str,
-        participant_type: str, participant_name: str, content: str
+        participant_type: str, participant_name: str, content: str,
+        mentions: List[str] = None, parent_id: str = None
     ):
+        """Send a message as a participant"""
         cm = self._cm()
         msg = chat_room_service.save_message(
-            room_id, participant_type, participant_id, participant_name, content
+            room_id=room_id,
+            sender_type=participant_type,
+            sender_name=participant_name,
+            content=content,
+            sender_id=str(participant_id),
+            mentions=mentions,
+            parent_id=parent_id
         )
-        await cm.broadcast_to_room(room_id, {"event": "message", "data": msg})
+        await cm.broadcast_to_room(room_id, {"event": "message", "data": {"message": msg}})
         return msg
 
 
diff --git a/luxx/services/room.py b/luxx/services/room.py
index e6fb445..9826153 100644
--- a/luxx/services/room.py
+++ b/luxx/services/room.py
@@ -2,10 +2,13 @@
 import json
 import uuid
 import logging
-from typing import List, Dict, Any, Optional, AsyncGenerator
+from typing import List, Dict, Optional
+from datetime import datetime
+
+from sqlalchemy.orm import joinedload
 
 from luxx.core.database import SessionLocal
-from luxx.models.room import ChatRoom, Agent
+from luxx.models.room import ChatRoom, Agent, RoomAgent
 from luxx.models.chat import Message
 from luxx.agents.base import BaseAgent
 
@@ -21,41 +24,42 @@ class ChatRoomService:
             db.close()
 
     def get_room_agents(self, room_id: str) -> List[BaseAgent]:
-        """Get active agents in a room from Message table"""
+        """Get active agents in a room from RoomAgent association table"""
         db = SessionLocal()
         try:
-            # Query distinct agent records from messages
-            messages = db.query(Message).filter(
-                Message.room_id == room_id,
-                Message.role == "agent"
-            ).distinct().all()
+            # Query from RoomAgent table (stable approach) with eager loading
+            room_agents = db.query(RoomAgent).options(
+                joinedload(RoomAgent.agent)
+            ).filter(
+                RoomAgent.room_id == room_id,
+                RoomAgent.is_active == True
+            ).all()
             
-            agent_ids = []
-            seen = set()
-            for msg in messages:
-                # Extract agent_id from content JSON
-                try:
-                    content = json.loads(msg.content) if msg.content else {}
-                    agent_id = content.get("agent_id")
-                    if agent_id and agent_id not in seen:
-                        seen.add(agent_id)
-                        agent_ids.append(agent_id)
-                except json.JSONDecodeError:
-                    pass
-
             agents = []
-            for agent_id in agent_ids:
-                agent_db = db.query(Agent).filter(
-                    Agent.id == agent_id,
-                    Agent.is_active == True
-                ).first()
-                if agent_db:
-                    agents.append(BaseAgent.from_model(agent_db))
+            for ra in room_agents:
+                if ra.agent and ra.agent.is_active:
+                    agents.append(BaseAgent.from_model(ra.agent))
             
             return sorted(agents, key=lambda a: a.priority)
         finally:
             db.close()
 
+    def get_room_agents_info(self, room_id: str) -> List[Dict]:
+        """Get room agents info with join metadata (using eager loading)"""
+        db = SessionLocal()
+        try:
+            # Use joinedload to eager load agent relationship
+            room_agents = db.query(RoomAgent).options(
+                joinedload(RoomAgent.agent)
+            ).filter(
+                RoomAgent.room_id == room_id,
+                RoomAgent.is_active == True
+            ).all()
+            
+            return [ra.to_dict() for ra in room_agents]
+        finally:
+            db.close()
+
     def get_agent(self, agent_id: str) -> Optional[BaseAgent]:
         db = SessionLocal()
         try:
@@ -75,6 +79,7 @@ class ChatRoomService:
             db.close()
 
     def create_room(self, name: str, owner_id: int, description: str = None, agent_ids: List[str] = None) -> Dict:
+        """Create a new chat room with optional initial agents"""
         db = SessionLocal()
         try:
             room = ChatRoom(
@@ -85,19 +90,31 @@ class ChatRoomService:
             )
             db.add(room)
 
-            # Record agents as join messages
+            # Add agents using RoomAgent association table
             for agent_id in (agent_ids or []):
-                msg = Message(
-                    id=str(uuid.uuid4()),
-                    room_id=room.id,
-                    role="agent",
-                    content=json.dumps({"type": "join", "agent_id": agent_id}),
-                    sender_name=agent_id
-                )
-                db.add(msg)
+                # Check if agent exists
+                agent = db.query(Agent).filter(Agent.id == agent_id).first()
+                if agent:
+                    room_agent = RoomAgent(
+                        room_id=room.id,
+                        agent_id=agent_id
+                    )
+                    db.add(room_agent)
+                    
+                    # Record system message
+                    msg = Message(
+                        id=str(uuid.uuid4()),
+                        room_id=room.id,
+                        sender_id=agent_id,
+                        sender_type="system",
+                        sender_name="System",
+                        role="system",
+                        content=json.dumps({"type": "agent_join", "agent_id": agent_id, "agent_name": agent.name})
+                    )
+                    db.add(msg)
 
             db.commit()
-            return room.to_dict()
+            return room.to_dict(include_agents=True)
         finally:
             db.close()
 
@@ -116,10 +133,14 @@ class ChatRoomService:
             db.close()
 
     def delete_room(self, room_id: str) -> bool:
+        """Delete a chat room and all related data"""
         db = SessionLocal()
         try:
             room = db.query(ChatRoom).filter(ChatRoom.id == room_id).first()
             if room:
+                # Delete related messages
+                db.query(Message).filter(Message.room_id == room_id).delete()
+                # RoomAgent will be cascade deleted due to relationship config
                 db.delete(room)
                 db.commit()
                 return True
@@ -160,6 +181,94 @@ class ChatRoomService:
         finally:
             db.close()
 
+    def add_agent_to_room(self, room_id: str, agent_id: str) -> bool:
+        """Add an agent to a chat room using RoomAgent association table"""
+        db = SessionLocal()
+        try:
+            room = db.query(ChatRoom).filter(ChatRoom.id == room_id).first()
+            if not room:
+                return False
+            
+            # Check if agent exists
+            agent = db.query(Agent).filter(Agent.id == agent_id).first()
+            if not agent:
+                return False
+
+            # Check if already in room
+            existing = db.query(RoomAgent).filter(
+                RoomAgent.room_id == room_id,
+                RoomAgent.agent_id == agent_id
+            ).first()
+            
+            if existing:
+                # Reactivate if was removed
+                if not existing.is_active:
+                    existing.is_active = True
+                    existing.joined_at = datetime.now()
+                db.commit()
+                return True
+
+            # Add new association
+            room_agent = RoomAgent(
+                room_id=room_id,
+                agent_id=agent_id
+            )
+            db.add(room_agent)
+            
+            # Record system message
+            msg = Message(
+                id=str(uuid.uuid4()),
+                room_id=room_id,
+                sender_id=agent_id,
+                sender_type="system",
+                sender_name="System",
+                role="system",
+                content=json.dumps({"type": "agent_join", "agent_id": agent_id, "agent_name": agent.name})
+            )
+            db.add(msg)
+            
+            db.commit()
+            return True
+        except Exception as e:
+            logger.error(f"Failed to add agent to room: {e}")
+            db.rollback()
+            return False
+        finally:
+            db.close()
+
+    def remove_agent_from_room(self, room_id: str, agent_id: str) -> bool:
+        """Remove an agent from a chat room"""
+        db = SessionLocal()
+        try:
+            # Soft delete: mark as inactive
+            result = db.query(RoomAgent).filter(
+                RoomAgent.room_id == room_id,
+                RoomAgent.agent_id == agent_id
+            ).update({"is_active": False})
+            
+            if result > 0:
+                # Record system message
+                agent = db.query(Agent).filter(Agent.id == agent_id).first()
+                msg = Message(
+                    id=str(uuid.uuid4()),
+                    room_id=room_id,
+                    sender_id=agent_id,
+                    sender_type="system",
+                    sender_name="System",
+                    role="system",
+                    content=json.dumps({"type": "agent_leave", "agent_id": agent_id, "agent_name": agent.name if agent else agent_id})
+                )
+                db.add(msg)
+                db.commit()
+                return True
+            return False
+        except Exception as e:
+            logger.error(f"Failed to remove agent from room: {e}")
+            db.rollback()
+            return False
+        finally:
+            db.close()
+
     def get_messages(self, room_id: str, limit: int = 50, before_id: str = None) -> List[Dict]:
         db = SessionLocal()
         try:
@@ -175,29 +284,59 @@ class ChatRoomService:
     def save_message(
         self,
         room_id: str,
-        role: str,
+        sender_type: str,
         sender_name: str,
         content: str,
+        sender_id: str = None,
         mentions: List[str] = None,
-        token_count: int = 0
+        token_count: int = 0,
+        is_streaming: bool = False,
+        stream_id: str = None,
+        parent_id: str = None
     ) -> Dict:
+        """Save a message to the room
+        
+        Args:
+            room_id: Room ID
+            sender_type: "user" | "agent" | "system"
+            sender_name: Display name of sender
+            content: Message content (can be plain text or JSON string)
+            sender_id: Sender ID (user_id or agent_id)
+            mentions: List of mentioned agent IDs
+            token_count: Token usage count
+            is_streaming: Whether this is a streaming message
+            stream_id: Streaming session ID
+            parent_id: Parent message ID (for replies)
+        """
         db = SessionLocal()
         try:
+            # Resolve sender_id from sender_name if not provided
+            if not sender_id:
+                sender_id = sender_name
+            
+            # Wrap plain text content in JSON format
+            if not content.startswith('{'):
+                content = json.dumps({"text": content})
+            
             msg = Message(
                 id=str(uuid.uuid4()),
                 room_id=room_id,
-                role=role,
+                sender_id=str(sender_id),
+                sender_type=sender_type,
                 sender_name=sender_name,
+                role=sender_type,  # Keep role in sync
                 content=content,
                 mentions=json.dumps(mentions) if mentions else None,
-                token_count=token_count
+                token_count=token_count,
+                is_streaming=is_streaming,
+                stream_id=stream_id,
+                parent_id=parent_id
             )
             db.add(msg)
             
             # Update room updated_at
             room = db.query(ChatRoom).filter(ChatRoom.id == room_id).first()
             if room:
-                from datetime import datetime
                 room.updated_at = datetime.now()
             
             db.commit()
@@ -206,8 +345,19 @@ class ChatRoomService:
             db.close()
 
     async def process_message(
-        self, room_id: str, user_message: str, sender_id: str, sender_name: str = None
+        self, room_id: str, user_message: str, sender_id: str, sender_name: str = None, 
+        context: dict = None, skip_save_user_message: bool = False
     ):
+        """Process a message and trigger agent responses
+        
+        Args:
+            room_id: Room ID
+            user_message: The user's message content
+            sender_id: Sender ID (user_id or agent_id)
+            sender_name: Sender display name
+            context: Additional context
+            skip_save_user_message: If True, skip saving user message (already saved by caller)
+        """
         room = self.get_room(room_id)
         if not room:
             yield {"event": "error", "data": {"content": "Chat room not found"}}
@@ -218,9 +368,10 @@ class ChatRoomService:
             yield {"event": "error", "data": {"content": "No agents available"}}
             return
 
-        # Check if sender is agent
+        # Determine sender type
         from luxx.agents.registry import agent_registry
         sender_is_agent = agent_registry.get(sender_id) is not None
+        sender_type = "agent" if sender_is_agent else "user"
         
         # Filter out sender if agent
         if sender_is_agent:
@@ -243,15 +394,108 @@ class ChatRoomService:
             yield {"event": "no_response", "data": {"message": "No agents triggered"}}
             return
 
-        # Get history
+        # Save user message (or use existing one if already saved)
+        if skip_save_user_message:
+            # Get the message that was already saved
+            from luxx.core.database import SessionLocal
+            from luxx.models.chat import Message
+            db = SessionLocal()
+            try:
+                recent_msg = db.query(Message).filter(
+                    Message.room_id == room_id
+                ).order_by(Message.created_at.desc()).first()
+                user_msg = recent_msg.to_dict() if recent_msg else {"id": None}
+            finally:
+                db.close()
+        else:
+            user_msg = self.save_message(
+                room_id=room_id,
+                sender_type="user",
+                sender_name=sender_name or "User",
+                content=user_message,
+                sender_id=str(sender_id),
+                mentions=[a.agent_id for a in triggered] if mentions else None
+            )
+        
+        # Get history for context
         messages = self.get_messages(room_id, limit=20)
         
-        # Stream responses
+        # Stream responses with new event format
         for agent in triggered:
-            async for event in agent.stream_response(user_message, messages):
-                yield event
+            stream_id = f"stream_{uuid.uuid4().hex[:8]}"
+            
+            # Emit stream_start
+            yield {
+                "event": "stream_start",
+                "data": {
+                    "stream_id": stream_id,
+                    "message_id": None,  # Will be set when complete
+                    "agent": {"id": agent.agent_id, "name": agent.name},
+                    "parent_message_id": user_msg["id"]
+                }
+            }
+            
+            full_content = ""
+            
+            # Parse SSE string and transform to new format
+            async for sse_str in agent.stream_response(user_message, messages):
+                # SSE format: "event: xxx\ndata: {...}\n\n"
+                try:
+                    event_type = "process_step"  # default
+                    data_str = ""
+                    
+                    for line in sse_str.strip().split('\n'):
+                        line = line.strip()
+                        if line.startswith('event: '):
+                            event_type = line[7:].strip()
+                        elif line.startswith('data: '):
+                            data_str = line[6:].strip()
+                    
+                    if not data_str:
+                        continue
+                    
+                    import json
+                    data = json.loads(data_str)
+                    
+                    if event_type == "process_step":
+                        step = data.get("step", {})
+                        full_content = step.get("content", full_content)
+                        yield {
+                            "event": "stream_step",
+                            "data": {
+                                "stream_id": stream_id,
+                                "step": {
+                                    "id": step.get("id", "step_0"),
+                                    "type": step.get("type", "text"),
+                                    "delta": step.get("content", ""),
+                                    "full": full_content,
+                                    "done": False
+                                }
+                            }
+                        }
+                    elif event_type == "done":
+                        yield {
+                            "event": "stream_end",
+                            "data": {
+                                "stream_id": stream_id,
+                                "content": full_content,
+                                "token_count": data.get("token_count", 0),
+                                "usage": data.get("usage", {})
+                            }
+                        }
+                    elif event_type == "error":
+                        yield {
+                            "event": "stream_error",
+                            "data": {
+                                "stream_id": stream_id,
+                                "error": data.get("content", "Unknown error")
+                            }
+                        }
+                except Exception as e:
+                    logger.error(f"Error parsing SSE string: {e}, raw: {sse_str[:100]}")
+                    continue
         
-        self.save_message(room_id, "user", sender_id, sender_name, user_message)
+        yield {"event": "message_sent", "data": {"message": user_msg}}
 
 
 # Global instance
diff --git a/luxx/services/room_ws.py b/luxx/services/room_ws.py
index 0302d7c..58696dd 100644
--- a/luxx/services/room_ws.py
+++ b/luxx/services/room_ws.py
@@ -1,4 +1,5 @@
 """WebSocket handler for Chat Rooms - unified user and agent participants."""
+import json
 import logging
 from typing import Dict, Set
 from fastapi import WebSocket, WebSocketDisconnect
@@ -9,6 +10,11 @@ from luxx.services.participant import participant_service
 logger = logging.getLogger(__name__)
 
 
+def _ws_message(event: str, data: dict) -> dict:
+    """Create a standardized WebSocket message"""
+    return {"event": event, "data": data}
+
+
 class ConnectionManager:
     def __init__(self):
         self._rooms: Dict[str, Set[WebSocket]] = {}
@@ -18,25 +24,44 @@ class ConnectionManager:
         await ws.accept()
         self._rooms.setdefault(room_id, set()).add(ws)
         self._info[ws] = {"type": ptype, "id": pid, "name": pname}
-        await ws.send_json({"event": "connected", "data": {"room_id": room_id, "type": ptype}})
+        await ws.send_json(_ws_message("connected", {
+            "room_id": room_id,
+            "participant_type": ptype,
+            "participant_id": pid,
+            "joined_at": None  # Will be set by caller
+        }))
 
     def disconnect(self, ws: WebSocket):
         info = self._info.pop(ws, {})
-        room = self._rooms.get(self._info.get(ws, {}).get("id"))
-        if room:
-            room.discard(ws)
-            if not room:
-                del self._rooms[room]
+        for room_id, room_ws in list(self._rooms.items()):
+            if ws in room_ws:
+                room_ws.discard(ws)
+                if not room_ws:
+                    del self._rooms[room_id]
+                break
         return info
 
     async def broadcast(self, room_id: str, msg: dict, exclude: WebSocket = None):
-        for ws in self._rooms.get(room_id, set()):
+        """Broadcast message to all clients in a room"""
+        ws_list = list(self._rooms.get(room_id, set()))
+        for ws in ws_list:
             if ws != exclude:
                 try:
                     await ws.send_json(msg)
                 except:
                     self.disconnect(ws)
 
+    async def send_to(self, ws: WebSocket, msg: dict):
+        """Send message to a specific client"""
+        try:
+            await ws.send_json(msg)
+        except:
+            self.disconnect(ws)
+
+    async def broadcast_to_room(self, room_id: str, msg: dict, exclude: WebSocket = None):
+        """Alias for broadcast - for compatibility with participant_service"""
+        await self.broadcast(room_id, msg, exclude)
+
     def size(self, room_id: str) -> int:
         return len(self._rooms.get(room_id, set()))
 
@@ -45,6 +70,7 @@ cm = ConnectionManager()
 
 
 async def websocket_handler(ws: WebSocket, room_id: str):
+    """Main WebSocket handler for chat rooms"""
     params = dict(ws.query_params)
     ptype = params.get("participant_type", "user")
     pid = params.get("participant_id", "")
@@ -54,27 +80,61 @@ async def websocket_handler(ws: WebSocket, room_id: str):
 
     room = chat_room_service.get_room(room_id)
     if not room:
-        await ws.send_json({"event": "error", "data": {"content": "Room not found"}})
+        await ws.send_json(_ws_message("error", {"content": "Room not found"}))
         await ws.close()
         return
 
+    # Register agent if applicable
     if ptype == "agent" and pid:
         agent = chat_room_service.get_agent(pid)
         if agent:
             participant_service.register_agent(agent)
 
     try:
+        # Get room agents info (only once)
+        agents = chat_room_service.get_room_agents_info(room_id)
+        
+        # Send room info
+        room_dict = room.to_dict()
+        room_dict["agents"] = agents
+        await ws.send_json(_ws_message("room_info", {
+            "room": room_dict
+        }))
+
         # Send history
-        await ws.send_json({"event": "history", "data": {"messages": chat_room_service.get_messages(room_id)}})
-        await ws.send_json({"event": "agents", "data": {
-            "agents": [a.to_dict() for a in chat_room_service.get_room_agents(room_id)]
-        }})
+        messages = chat_room_service.get_messages(room_id)
+        await ws.send_json(_ws_message("history", {
+            "messages": messages,
+            "has_more": False
+        }))
 
-        await cm.broadcast(room_id, {
-            "event": "system",
-            "data": {"content": f"{pname} joined", "type": f"{ptype}_join"}
-        }, exclude=ws)
+        # Send agents list (from RoomAgent table - stable source)
+        await ws.send_json(_ws_message("agents", {
+            "agents": agents,
+            "count": len(agents)
+        }))
 
+        # Broadcast join event
+        join_msg = chat_room_service.save_message(
+            room_id=room_id,
+            sender_type="system",
+            sender_name="System",
+            content=json.dumps({
+                "type": "participant_join",
+                "participant_type": ptype,
+                "participant_id": pid,
+                "participant_name": pname
+            }),
+            sender_id=pid
+        )
+        await cm.broadcast(room_id, _ws_message("system", {
+            "type": "participant_join",
+            "sender": {"id": pid, "type": ptype, "name": pname},
+            "content": f"{pname} joined the room",
+            "message": join_msg
+        }), exclude=ws)
+
+        # Main message loop
         while True:
             data = await ws.receive_json()
             action = data.get("action")
@@ -84,27 +144,94 @@ async def websocket_handler(ws: WebSocket, room_id: str):
                 if not content:
                     continue
 
-                sid = pid if ptype == "agent" else str(data.get("user_id", pid or "anonymous"))
-                sname = pname if ptype == "agent" else data.get("user_name", pname or "Anonymous")
+                reply_to = data.get("reply_to")  # Optional: reply to a message
+                mentions = data.get("mentions", [])  # Optional: mentioned agents
 
-                async for event in participant_service.process_message(
-                    room_id, content, sid, sname, ptype
+                # Save user message first
+                user_msg = chat_room_service.save_message(
+                    room_id=room_id,
+                    sender_type=ptype,
+                    sender_name=pname,
+                    content=content,
+                    sender_id=pid,
+                    mentions=mentions,
+                    parent_id=reply_to
+                )
+
+                # Broadcast user message
+                await cm.broadcast(room_id, _ws_message("message", {
+                    "message": user_msg
+                }))
+
+                # Process and broadcast agent responses
+                sender_id = pid if ptype == "agent" else str(data.get("user_id", pid or "anonymous"))
+                sender_name = pname if ptype == "agent" else data.get("user_name", pname or "Anonymous")
+
+                async for event in chat_room_service.process_message(
+                    room_id, content, sender_id, sender_name, skip_save_user_message=True
                 ):
-                    if event.get("event") in ["process_step", "done", "error"]:
-                        await cm.broadcast(room_id, {
-                            "event": event["event"],
-                            "data": event.get("data", {}),
-                            "agent_id": event.get("agent_id")
-                        })
+                    # Broadcast stream events to all clients
+                    await cm.broadcast(room_id, event)
+
+                    # Also send the final message to message list
+                    if event.get("event") == "stream_end":
+                        stream_data = event.get("data", {})
+                        agent_info = event.get("data", {}).get("agent")
+                        
+                        # Save agent response as final message
+                        agent_msg = chat_room_service.save_message(
+                            room_id=room_id,
+                            sender_type="agent",
+                            sender_name=agent_info.get("name", "Agent") if agent_info else "Agent",
+                            content=stream_data.get("content", ""),
+                            sender_id=agent_info.get("id") if agent_info else None,
+                            token_count=stream_data.get("token_count", 0),
+                            parent_id=user_msg.get("id")
+                        )
+                        
+                        # Broadcast saved message
+                        await cm.broadcast(room_id, _ws_message("message", {
+                            "message": agent_msg
+                        }))
+
+            elif action == "join":
+                # Handle re-join with updated info
+                ptype = data.get("participant_type", ptype)
+                pid = data.get("participant_id", pid)
+                pname = data.get("participant_name", pname)
+                cm._info[ws] = {"type": ptype, "id": pid, "name": pname}
+                await ws.send_json(_ws_message("joined", {
+                    "participant_type": ptype,
+                    "participant_id": pid,
+                    "participant_name": pname
+                }))
 
             elif action == "ping":
-                await ws.send_json({"event": "pong", "data": {}})
+                await ws.send_json(_ws_message("pong", {}))
 
     except WebSocketDisconnect:
-        await cm.broadcast(room_id, {"event": "system", "data": {"content": f"{pname} left", "type": "leave"}})
+        # Broadcast leave event
+        leave_msg = chat_room_service.save_message(
+            room_id=room_id,
+            sender_type="system",
+            sender_name="System",
+            content=json.dumps({
+                "type": "participant_leave",
+                "participant_type": ptype,
+                "participant_id": pid,
+                "participant_name": pname
+            }),
+            sender_id=pid
+        )
+        await cm.broadcast(room_id, _ws_message("system", {
+            "type": "participant_leave",
+            "sender": {"id": pid, "type": ptype, "name": pname},
+            "content": f"{pname} left the room",
+            "message": leave_msg
+        }))
     except Exception as e:
         logger.error(f"WebSocket error: {e}")
-        await cm.broadcast(room_id, {"event": "error", "data": {"content": str(e)}})
+        await cm.broadcast(room_id, _ws_message("error", {"content": str(e)}))
     finally:
         cm.disconnect(ws)