diff --git a/daemon/mgmt/command-validator.hpp b/daemon/mgmt/command-validator.hpp
index 290cabd..0162796 100644
--- a/daemon/mgmt/command-validator.hpp
+++ b/daemon/mgmt/command-validator.hpp
@@ -7,6 +7,7 @@
 #ifndef NFD_MGMT_COMMAND_VALIDATOR_HPP
 #define NFD_MGMT_COMMAND_VALIDATOR_HPP
 
+#include "common.hpp"
 #include "config-file.hpp"
 #include <ndn-cpp-dev/util/command-interest-validator.hpp>
 
@@ -19,6 +20,7 @@
   class Error : public std::runtime_error
   {
   public:
+    explicit
     Error(const std::string& what)
       : std::runtime_error(what)
     {