diff --git a/backend/ai-core/cmd/main.go b/backend/ai-core/cmd/main.go
index 4be5e99..5b157e7 100644
--- a/backend/ai-core/cmd/main.go
+++ b/backend/ai-core/cmd/main.go
@@ -1077,7 +1077,18 @@ func handleChat(
 	}
 
 	// 平台静默观察模式：只记录消息、提取记忆、触发后台思考，不生成回复。
-	if req.Mode == "platform_silent" {
+	if req.Mode == "group_ambient" {
+			// 群聊环境消息 — 审查是否值得回应
+			message := req.Message
+			ctxBuilder.CacheMessage(req.SessionID, model.RoleUser, message)
+			if thinker != nil {
+				thinker.RecordUserMessage(req.SessionID)
+			}
+			// 在消息前加审查指令，让 LLM 自己判断是否插话
+			req.Message = "【群聊环境消息】" + message + "\n\n你不需要回复这条消息，除非你真有特别相关的话要说。如果不想说话，只用 <action> 在心里轻轻想一下即可，不用发消息。"
+			req.Mode = "text"
+		}
+		if req.Mode == "platform_silent" {
 		if thinker != nil {
 			thinker.RecordUserMessage(req.SessionID)
 			if req.Source.Platform != "" && req.Source.BotUID != "" {