diff --git a/backend/controllers/ai.go b/backend/controllers/ai.go
index 1514fc0..0a8e9f8 100644
--- a/backend/controllers/ai.go
+++ b/backend/controllers/ai.go
@@ -57,7 +57,7 @@ func (ctrl *AIController) TestConfig(c *gin.Context) {
 	if req.Model != "" {
 		cfg.Model = req.Model
 	}
-	// 传了新的 key 就用新的（掩码/空则沿用已保存的）
+	// key 解析:传新值才覆盖;掩码/空一律沿用已保存的真实 key(GetAIConfig 返回的是解密后的真值)
 	if req.APIKey != "" && !containsMask(req.APIKey) {
 		cfg.APIKey = req.APIKey
 	}