diff --git a/internal/handler/routes.go b/internal/handler/routes.go
index 24427f0..18fc977 100644
--- a/internal/handler/routes.go
+++ b/internal/handler/routes.go
@@ -186,6 +186,8 @@ func registerYggdrasilRoutesWithDI(v1 *gin.RouterGroup, h *Handlers) {
 			mcServices.POST("/player/attributes", h.Friends.UpdateAttributes)
 			mcServices.POST("/presence", h.Friends.UpdatePresence)
 			mcServices.GET("/privacy/blocklist", h.Friends.GetBlocklist)
+			// MC 1.21.7 /whitelist add 查询单用户名 UUID（authlib-injector issue #277）
+			mcServices.GET("/minecraft/profile/lookup/name/:name", h.Yggdrasil.LookupProfileByName)
 		}
 
 		authserver := ygg.Group("/authserver")
diff --git a/internal/handler/yggdrasil_handler.go b/internal/handler/yggdrasil_handler.go
index 4376fc9..b613927 100644
--- a/internal/handler/yggdrasil_handler.go
+++ b/internal/handler/yggdrasil_handler.go
@@ -682,6 +682,41 @@ func (h *YggdrasilHandler) GetProfileByName(c *gin.Context) {
 	c.JSON(http.StatusOK, result)
 }
 
+// LookupProfileByName 单用户名查 UUID（authlib-injector issue #277 / MC 1.21.7）
+// @Summary MinecraftServices 按用户名查 UUID
+// @Description 对应官方 api.minecraftservices.com/minecraft/profile/lookup/name/{name}，
+// @Description 1.21.7 的 /whitelist add 等命令会请求该接口。authlib-injector 把
+// @Description api.minecraftservices.com override 到 {apiRoot}/minecraftservices。
+// @Description 返回 {id,name}，未找到返回 404。
+// @Tags Yggdrasil
+// @Produce json
+// @Param name path string true "用户名"
+// @Success 200 {object} model.NameAndId "档案标识"
+// @Failure 404 {object} map[string]string "档案不存在"
+// @Router /api/yggdrasil/minecraftservices/minecraft/profile/lookup/name/{name} [get]
+func (h *YggdrasilHandler) LookupProfileByName(c *gin.Context) {
+	name := c.Param("name")
+	if name == "" {
+		c.JSON(http.StatusNotFound, gin.H{"error": "用户不存在"})
+		return
+	}
+
+	result, err := h.container.ProfileService.ProfileSearchByNameSingle(c.Request.Context(), name)
+	if err != nil {
+		h.logger.Warn("按用户名查档失败", zap.String("name", name), zap.Error(err))
+		c.JSON(http.StatusNotFound, gin.H{"error": "用户不存在"})
+		return
+	}
+	if result == nil {
+		h.logger.Info("用户名未找到", zap.String("name", name))
+		c.JSON(http.StatusNotFound, gin.H{"error": "用户不存在"})
+		return
+	}
+
+	h.logger.Info("成功获取档案", zap.String("name", name), zap.String("uuid", result.ID))
+	c.JSON(http.StatusOK, result)
+}
+
 // GetMetaData 获取Yggdrasil元数据
 // @Summary Yggdrasil元数据
 // @Description Yggdrasil协议: 获取服务器元数据