diff --git a/tools/src/main/scala/caliban/tools/ClientWriter.scala b/tools/src/main/scala/caliban/tools/ClientWriter.scala
index 04514feb3..d7bb45fda 100644
--- a/tools/src/main/scala/caliban/tools/ClientWriter.scala
+++ b/tools/src/main/scala/caliban/tools/ClientWriter.scala
@@ -862,6 +862,7 @@ object ClientWriter {
     "return",
     "sealed",
     "super",
+    "then",
     "this",
     "throw",
     "trait",