diff --git a/backend/internal/eino/nodes_stt.go b/backend/internal/eino/nodes_stt.go
index 0f63a05..ca915da 100644
--- a/backend/internal/eino/nodes_stt.go
+++ b/backend/internal/eino/nodes_stt.go
@@ -10,6 +10,7 @@ import (
 	"github.com/hhs/camtalk/internal/ai/stt"
 	"github.com/hhs/camtalk/internal/logger"
 	"github.com/hhs/camtalk/internal/models"
+	"github.com/hhs/camtalk/internal/util"
 )
 
 // NewSTTLambda 创建 STT Lambda 节点。
@@ -39,8 +40,10 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 
 		// 文本输入模式：跳过 STT
 		if input.Text != "" {
-			log.Infow("使用文本输入，跳过 STT",
-				"request_id", requestID, "text", input.Text)
+			log.Debugw("text input mode, skipping stt",
+				"request_id", requestID,
+				"text_len", len(input.Text),
+				"text_preview", util.Truncate(input.Text, 50))
 
 			// 发送 stt_result 保持前端消息流一致性
 			if sender != nil {
@@ -101,7 +104,10 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 			text = "（未识别到语音）"
 		}
 
-		log.Infow("语音识别完成", "request_id", requestID, "text", text)
+		log.Debugw("stt recognition completed",
+			"request_id", requestID,
+			"text_len", len(text),
+			"text_preview", util.Truncate(text, 50))
 
 		// 发送 stt_result
 		if sender != nil {