diff --git a/packages/client/src/api/hermes/group-chat.ts b/packages/client/src/api/hermes/group-chat.ts
index 39d3eea7b..bb60832f2 100644
--- a/packages/client/src/api/hermes/group-chat.ts
+++ b/packages/client/src/api/hermes/group-chat.ts
@@ -48,6 +48,7 @@ export interface ChatMessage {
     reasoning_details?: string | null
     reasoning_content?: string | null
     isStreaming?: boolean
+    isIncomplete?: boolean
     toolName?: string
     toolCallId?: string
     toolArgs?: unknown
@@ -55,6 +56,8 @@ export interface ChatMessage {
     toolResult?: unknown
     toolStatus?: 'running' | 'done' | 'error'
     attachments?: Array<{ id: string; name: string; type: string; size: number; url: string }>
+    /** Captured at stream_start and never overwritten; used for stable sort order. */
+    firstSeenAt?: number
 }
 
 export interface MemberInfo {
diff --git a/packages/client/src/stores/hermes/group-chat.ts b/packages/client/src/stores/hermes/group-chat.ts
index 2f7d0eb37..83933413b 100644
--- a/packages/client/src/stores/hermes/group-chat.ts
+++ b/packages/client/src/stores/hermes/group-chat.ts
@@ -110,6 +110,8 @@ function mergeFinalMessage(existing: ChatMessage | null, msg: ChatMessage): Chat
         reasoning: hasText(msg.reasoning) ? msg.reasoning : existing?.reasoning ?? msg.reasoning ?? null,
         reasoning_content: hasText(msg.reasoning_content) ? msg.reasoning_content : existing?.reasoning_content ?? msg.reasoning_content ?? null,
         isStreaming: false,
+        isIncomplete: msg.isIncomplete ?? existing?.isIncomplete ?? undefined,
+        firstSeenAt: existing?.firstSeenAt || msg.firstSeenAt,
         attachments: existing?.attachments || msg.attachments,
     }
 }
@@ -284,7 +286,7 @@ const currentUserAvatar = ref('')
     }
 
     // ─── Computed ───────────────────────────────────────────
-    const sortedMessages = computed(() => mapGroupMessages([...messages.value].sort((a, b) => a.timestamp - b.timestamp)))
+    const sortedMessages = computed(() => mapGroupMessages([...messages.value].sort((a, b) => (a.firstSeenAt || a.timestamp) - (b.firstSeenAt || b.timestamp))))
 
     const memberNames = computed(() => {
         return members.value.map(m => m.name)
@@ -374,6 +376,8 @@ const currentUserAvatar = ref('')
                 !m.tool_calls?.length
             ))
             msg.isStreaming = true
+            // Capture firstSeenAt once — never overwritten, used for stable sort
+            msg.firstSeenAt = msg.firstSeenAt || msg.timestamp || Date.now()
             const idx = messages.value.findIndex(m => m.id === msg.id)
             if (idx >= 0) {
                 const existing = messages.value[idx]
@@ -418,9 +422,10 @@ const currentUserAvatar = ref('')
             messages.value = [...messages.value]
         })
 
-        socket.on('message_stream_end', (data: { roomId: string; id: string }) => {
+        socket.on('message_stream_end', (data: { roomId: string; id: string; finishReason?: string }) => {
             if (data.roomId !== currentRoomId.value) return
             const idx = messages.value.findIndex(m => m.id === data.id)
+            const isIncomplete = data.finishReason && data.finishReason !== 'stop'
             if (
                 idx >= 0 &&
                 !messages.value[idx].content?.trim() &&
@@ -429,9 +434,12 @@ const currentUserAvatar = ref('')
             ) {
                 messages.value.splice(idx, 1)
             } else if (idx >= 0) {
+                const content = messages.value[idx].content || ''
                 messages.value[idx] = {
                     ...messages.value[idx],
                     isStreaming: false,
+                    isIncomplete: isIncomplete || undefined,
+                    content: isIncomplete && content ? content + '  ⚠️ [回复中断]' : content,
                 }
                 messages.value = [...messages.value]
                 if (needsFinalContentRecovery(messages.value[idx])) {
diff --git a/packages/server/src/services/hermes/group-chat/agent-clients.ts b/packages/server/src/services/hermes/group-chat/agent-clients.ts
index 70a7e8c19..3cee2a8e1 100644
--- a/packages/server/src/services/hermes/group-chat/agent-clients.ts
+++ b/packages/server/src/services/hermes/group-chat/agent-clients.ts
@@ -290,9 +290,9 @@ class AgentClient {
         this.socket!.emit('message_reasoning_delta', { roomId, id: messageId, delta })
     }
 
-    emitMessageStreamEnd(roomId: string, messageId: string): void {
+    emitMessageStreamEnd(roomId: string, messageId: string, finishReason?: string): void {
         this.ensureConnected()
-        this.socket!.emit('message_stream_end', { roomId, id: messageId })
+        this.socket!.emit('message_stream_end', { roomId, id: messageId, finishReason: finishReason || 'stop' })
     }
 
     getJoinedRooms(): string[] {
@@ -561,7 +561,7 @@ class AgentClient {
             if (lastChunk?.status === 'error') {
                 logger.error(`[AgentClients] ${this.name}: bridge response failed: ${lastChunk.error || 'unknown error'}`)
                 await this.sendAgentErrorMessage(roomId, streamMessageId, lastChunk.error || 'Run failed', msg, reasoningContent)
-                this.emitMessageStreamEnd(roomId, streamMessageId)
+                this.emitMessageStreamEnd(roomId, streamMessageId, 'error')
                 this.stopTyping(roomId)
                 onStatus?.('ready')
                 return
@@ -581,20 +581,20 @@ class AgentClient {
                     reasoning: reasoningContent || null,
                     reasoning_content: reasoningContent || null,
                 })
-                this.emitMessageStreamEnd(roomId, streamMessageId)
+                this.emitMessageStreamEnd(roomId, streamMessageId, 'stop')
                 await this.refreshRoomFullContextEstimate(roomId, sessionId, bridge, instructions, modelContext)
                 onStatus?.('ready')
                 return
             }
             logger.warn(`[AgentClients] ${this.name}: bridge response completed without content`)
-            this.emitMessageStreamEnd(roomId, streamMessageId)
+            this.emitMessageStreamEnd(roomId, streamMessageId, 'stop')
             this.stopTyping(roomId)
             onStatus?.('ready')
         } catch (err: any) {
             logger.error(`[AgentClients] ${this.name}: error handling message: ${err.message}`)
             try {
                 await this.sendAgentErrorMessage(roomId, streamMessageId, err, msg, reasoningContent)
-                if (streamStarted) this.emitMessageStreamEnd(roomId, streamMessageId)
+                if (streamStarted) this.emitMessageStreamEnd(roomId, streamMessageId, 'error')
             } catch (sendErr: any) {
                 logger.warn(`[AgentClients] ${this.name}: failed to send error message: ${sendErr.message}`)
             }