diff --git a/tools/bit/command.h b/tools/bit/command.h
index fb44900b0806f..dd7103e10fe75 100644
--- a/tools/bit/command.h
+++ b/tools/bit/command.h
@@ -25,7 +25,7 @@ using namespace std;
 
 struct Command
 {
-    Command(const string& prog);
+    explicit Command(const string& prog);
     ~Command();
 
     void AddArg(const string& arg);
diff --git a/tools/streaming_proto/Errors.h b/tools/streaming_proto/Errors.h
index f14bbfd55b5fd..bddd9819e8f59 100644
--- a/tools/streaming_proto/Errors.h
+++ b/tools/streaming_proto/Errors.h
@@ -11,7 +11,7 @@ using namespace std;
 struct Error
 {
     Error();
-    explicit Error(const Error& that);
+    Error(const Error& that);
     Error(const string& filename, int lineno, const char* message);
 
     string filename;