diff --git a/libc/include/termio.h b/libc/include/termio.h
index 9e26956..9ba3ce8 100644
--- a/libc/include/termio.h
+++ b/libc/include/termio.h
@@ -1 +1,10 @@
+#pragma once
+
+/**
+ * @file termio.h
+ * @brief Historical alternative to `<termios.h>`.
+ *
+ * New code should use `<termios.h>` directly.
+ */
+
 #include <termios.h>