diff --git a/src/components/graph/NodeTooltip.vue b/src/components/graph/NodeTooltip.vue
index 5f06386ba..6419326d6 100644
--- a/src/components/graph/NodeTooltip.vue
+++ b/src/components/graph/NodeTooltip.vue
@@ -83,7 +83,7 @@ const onIdle = () => {
     const inputName = node.inputs[inputSlot].name
     const translatedTooltip = st(
       `nodeDefs.${normalizeI18nKey(node.type ?? '')}.inputs.${normalizeI18nKey(inputName)}.tooltip`,
-      nodeDef.inputs[inputName]?.tooltip ?? ''
+      nodeDef?.inputs[inputName]?.tooltip ?? ''
     )
     return showTooltip(translatedTooltip)
   }
@@ -97,7 +97,7 @@ const onIdle = () => {
   if (outputSlot !== -1) {
     const translatedTooltip = st(
       `nodeDefs.${normalizeI18nKey(node.type ?? '')}.outputs.${outputSlot}.tooltip`,
-      nodeDef.outputs[outputSlot]?.tooltip ?? ''
+      nodeDef?.outputs[outputSlot]?.tooltip ?? ''
     )
     return showTooltip(translatedTooltip)
   }
@@ -107,7 +107,7 @@ const onIdle = () => {
   if (widget && !isDOMWidget(widget)) {
     const translatedTooltip = st(
       `nodeDefs.${normalizeI18nKey(node.type ?? '')}.inputs.${normalizeI18nKey(widget.name)}.tooltip`,
-      nodeDef.inputs[widget.name]?.tooltip ?? ''
+      nodeDef?.inputs[widget.name]?.tooltip ?? ''
     )
     // Widget tooltip can be set dynamically, current translation collection does not support this.
     return showTooltip(widget.tooltip ?? translatedTooltip)