diff --git a/biopet/biopet.wdl b/biopet/biopet.wdl
index e560e72e67950953ab0c548a7a88e7f30747ad32..8900983500d3d906ee52f2b8054a0818e7efaaa2 100644
--- a/biopet/biopet.wdl
+++ b/biopet/biopet.wdl
@@ -205,7 +205,7 @@ task FastqSync {
 task ReorderGlobbedScatters {
     input {
         Array[File]+ scatters
-        String scatterDir
+        File scatterDir
         # Should not be changed from the main pipeline. As it should not influence results.
         String dockerTag = "3.6"
     }