diff --git a/include/command_line_interface.h b/include/command_line_interface.h
index 68ae8b4..b990a7b 100644
--- a/include/command_line_interface.h
+++ b/include/command_line_interface.h
@@ -20,7 +20,7 @@ namespace Hanabi {
     boost::optional<bool> interactive {};
     bool quiet { false };
     // If this holds std::monostate, then all clue numbers are evaluated
-    std::variant<std::monostate, clue_t> clue_spec;
+    std::variant<std::monostate, clue_t> clue_spec {static_cast<clue_t>(0)};
     bool recursive { false };
   };