diff --git a/include/mtl/string.hpp b/include/mtl/string.hpp
index b4ba97e..f6cd944 100644
--- a/include/mtl/string.hpp
+++ b/include/mtl/string.hpp
@@ -107,7 +107,11 @@ public:
 	
 	void clear();
 
-	// Insert from self only works if index is after input range
+	/**
+	 * \brief Insert a string at the given index
+	 *
+	 * Inserting a substring of the destination string is not supported.
+	 */
 	istring& insert(size_t index, const istring& str);
 	istring& insert(size_t index, const istring& str, size_t s_index, size_t count = npos);
 	istring& insert(size_t index, const string_view& str);