diff --git a/survivor.wdl b/survivor.wdl
index 8b0360d87fe7e783d01a3f6e128a44590e16ef53..de232405b4d617a46a785f7aa9970a45f474b60b 100644
--- a/survivor.wdl
+++ b/survivor.wdl
@@ -44,9 +44,9 @@ task Merge {
         fileList \
         ~{breakpointDistance} \
         ~{suppVecs} \
-        ~{true=1 false=0 svType} \
-        ~{true=1 false=0 strandType} \
-        ~{true=1 false=0 distanceBySvSize} \
+        ~{true='1' false='0' svType} \
+        ~{true='1' false='0' strandType} \
+        ~{true='1' false='0' distanceBySvSize} \
         ~{minSize} \
         ~{outputPath}
     }