diff --git a/api/handler/chatimpl/chat_handler.go b/api/handler/chatimpl/chat_handler.go
index d56d00aa..ebbf9f2a 100644
--- a/api/handler/chatimpl/chat_handler.go
+++ b/api/handler/chatimpl/chat_handler.go
@@ -252,15 +252,17 @@ func (h *ChatHandler) sendMessage(ctx context.Context, session *types.ChatSessio
 
 			// loading the role context
 			var messages []types.Message
-			err := utils.JsonDecode(role.Context, &messages)
-			if err == nil {
-				for _, v := range messages {
-					tks, _ := utils.CalcTokens(v.Content, req.Model)
-					if tokens+tks >= types.ModelToTokens[req.Model] {
-						break
+			if len(messages) > 0 {
+				err := utils.JsonDecode(role.Context, &messages)
+				if err == nil {
+					for _, v := range messages {
+						tks, _ := utils.CalcTokens(v.Content, req.Model)
+						if tokens+tks >= types.ModelToTokens[req.Model] {
+							break
+						}
+						tokens += tks
+						chatCtx = append(chatCtx, v)
 					}
-					tokens += tks
-					chatCtx = append(chatCtx, v)
 				}
 			}