diff --git a/src/lib/CLIAppBase.hx b/src/lib/CLIAppBase.hx
index 3489cda..48c7218 100644
--- a/src/lib/CLIAppBase.hx
+++ b/src/lib/CLIAppBase.hx
@@ -40,12 +40,12 @@ abstract class CLIAppBase implements Process {
 
 	private function registerSyncSubcommand(command: String, callback: (Array<String>) -> Bool, synopsis: String = null) {
 		_subcommandsSync.set(command, callback);
-		_subcommandsSynopsis.push(command + " " + synopsis);
+		_subcommandsSynopsis.push(command + " " + (synopsis ?? ""));
 	}
 
 	private function registerAsyncSubcommand(command: String, callback: (Array<String>) -> Future<Bool>, synopsis: String = null) {
 		_subcommandsAsync.set(command, callback);
-		_subcommandsSynopsis.push(command + " " + synopsis);
+		_subcommandsSynopsis.push(command + " " + (synopsis ?? ""));
 	}
 
 	private function printHelp() {