diff --git a/macs2.wdl b/macs2.wdl
index 53be0abd4fdc36342b95c5d2db4e86134b399bd8..854db814a062b1c85b7764d6cfd742ba8bb476a5 100644
--- a/macs2.wdl
+++ b/macs2.wdl
@@ -36,7 +36,7 @@ task PeakCalling {
         Float pval_thres = 0.01
         Boolean bdg = true
         String keepdup = "auto"
-        String callsummits = true
+        Boolean callsummits = true
         Int timeMinutes = 600  # Default to 10 hours
         String memory = "8G"
         String dockerImage = "quay.io/biocontainers/macs2:2.1.2--py27r351_0"