diff --git a/demo/alu.cpp b/demo/alu.cpp
index 0a5d18a..08c4f00 100644
--- a/demo/alu.cpp
+++ b/demo/alu.cpp
@@ -1,4 +1,4 @@
-#include "../include/tools"
+#include "../include/tools.h"
 #include <iostream>
 
 bool reset;
diff --git a/docs/help.md b/docs/help.md
index 0e66470..05cd6a7 100644
--- a/docs/help.md
+++ b/docs/help.md
@@ -18,7 +18,7 @@ e.g. `g++ -std=c++2b ...`
 
 This is a header-only library, which means you just need to include all your required headers in your project.
 
-We strongly recommend you to include `include/tools` to simply include all the headers.
+We strongly recommend you to include `include/tools.h` to simply include all the headers.
 
 ```cpp
 #include "include/tools.h"
diff --git a/include/tools b/include/tools.h
similarity index 100%
rename from include/tools
rename to include/tools.h