diff --git a/nac3core/irrt/irrt/utils.hpp b/nac3core/irrt/irrt/utils.hpp
index a1707530..ea012c08 100644
--- a/nac3core/irrt/irrt/utils.hpp
+++ b/nac3core/irrt/irrt/utils.hpp
@@ -11,6 +11,9 @@ const T& min(const T& a, const T& b) {
     return a > b ? b : a;
 }
 
+/**
+ * @brief Compare contents of two arrays with the same length.
+ */
 template <typename T>
 bool arrays_match(int len, T* as, T* bs) {
     for (int i = 0; i < len; i++) {