diff --git a/kernel/model/graph.go b/kernel/model/graph.go
index c3f78d4fb..8f8c21b04 100644
--- a/kernel/model/graph.go
+++ b/kernel/model/graph.go
@@ -47,7 +47,7 @@ type GraphNode struct {
 type GraphLink struct {
 	From   string       `json:"from"`
 	To     string       `json:"to"`
-	Ref    bool         `json:"-"`
+	Ref    bool         `json:"ref"`
 	Arrows *GraphArrows `json:"arrows"`
 }