diff --git a/toolflow/src/main/scala/com/minres/tgc/hammer/cli/HammerConf.scala b/toolflow/src/main/scala/com/minres/tgc/hammer/cli/HammerConf.scala
index 3db7013..86ce571 100644
--- a/toolflow/src/main/scala/com/minres/tgc/hammer/cli/HammerConf.scala
+++ b/toolflow/src/main/scala/com/minres/tgc/hammer/cli/HammerConf.scala
@@ -9,7 +9,7 @@ class HammerConf(arguments: Seq[String]) extends ScallopConf(arguments) {
   val outputDirectory: ScallopOption[Path] = opt[Path](default = Some("output".path()), descr = "The base output directory")
   val verbose: ScallopOption[Int] = tally(short = 'v', descr = "Controls the logging of tgc-hammer itself, using it multiple times (-vv) will print more. (0x => WARN, 1x => INFO, 2x => DEBUG, 3x => TRACE)")
   val emptyOutputDir: ScallopOption[Boolean] = toggle(default = Some(true), descrYes = "Whether to empty the output directory at the start; defaults to true")
-  val printToolOutput: ScallopOption[Boolean] = toggle(descrYes = s"Whether to directly print all output of the underlying tools to the terminal. Otherwise the output will be written to files in `logs` folder in the selected outputDirectory")
+  val printToolOutput: ScallopOption[Boolean] = toggle(descrYes = s"Whether to directly print all output of the underlying tools to the terminal. Otherwise the output will be written to files in `logs` folder in the selected outputDirectory", default = Some(false))
   addSubcommand(new LongnailCommand)
   addSubcommand(new TreenailCommand)
   addSubcommand(new LongnailMergeCommand)