diff --git a/types.go b/types.go
index eacbb06..3cac8b5 100644
--- a/types.go
+++ b/types.go
@@ -195,6 +195,9 @@ type MisterScriptArgs struct {
 	GlobalArgs
 	// Hidden controls whether the script window is hidden.
 	Hidden string `advarg:"hidden"`
+	// LaunchOriginID sets LAUNCH_ORIGIN_ID in the script's environment. It is
+	// left unset when empty.
+	LaunchOriginID string `advarg:"launch_origin_id"`
 }
 
 // PlaytimeExtendArgs contains advanced arguments for the playtime.extend
diff --git a/types_advargs_test.go b/types_advargs_test.go
index c03206e..116de72 100644
--- a/types_advargs_test.go
+++ b/types_advargs_test.go
@@ -46,6 +46,12 @@ func TestSlotAdvargFields(t *testing.T) {
 	requireAdvargField(t, reflect.TypeOf(PlaylistArgs{}), "slot")
 }
 
+func TestMisterScriptLaunchOriginAdvargField(t *testing.T) {
+	t.Parallel()
+
+	requireAdvargField(t, reflect.TypeOf(MisterScriptArgs{}), "launch_origin_id")
+}
+
 func requireAdvargField(t *testing.T, typ reflect.Type, tag string) {
 	t.Helper()