diff --git a/scripts/add-thought.lua b/scripts/add-thought.lua
index 2bd648edd..3739f85c7 100644
--- a/scripts/add-thought.lua
+++ b/scripts/add-thought.lua
@@ -30,6 +30,7 @@ validArgs = validArgs or utils.invert({
  'emotion',
  'severity',
  'strength',
+ 'subthought',
  'gui'
 })