diff --git a/src/main.c b/src/main.c
index 430e662..73d2edf 100644
--- a/src/main.c
+++ b/src/main.c
@@ -7,6 +7,15 @@
 #define ANSI_COLOR_RED "\x1b[31m"
 #define ANSI_COLOR_RESET "\x1b[0m"
 
+/**
+ * @brief Assert a condition
+ * @details If the condition is false, print an error message
+ *          and exit the program
+ *
+ * @param condition The condition to assert
+ * @param message The message to print if the condition is false
+ * @return 0 if the condition is true
+ */
 int assert(bool condition, const char *message) {
   if (!condition) {
     printf(ANSI_COLOR_RED "Assertion failed: %s\n" ANSI_COLOR_RESET, message);
diff --git a/src/tree.h b/src/tree.h
index ef90695..c89a820 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -5,20 +5,37 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-// A regular node with a left and right branch
+/**
+ * @brief A node in a binary tree
+ * @details A node in a binary tree has some data
+ *          and can have a left and right branch
+ */
 struct Node {
+  /** @brief The data of the node */
   int data;
-  struct Node *left, *right;
+
+   /** @see Node */
+  struct Node *left;
+
+  /** @see Node */
+  struct Node *right;
 };
 typedef struct Node Node;
 
-// Represents a tree with a root node
+/** @brief Represents a tree with a root node */
 struct Tree {
+  /** @brief The root node of the tree */
   Node *root;
 };
 typedef struct Tree Tree;
 
-// Insert some data into the tree
+/**
+ * @brief Insert some data into the tree
+ * 
+ * @param tree 
+ * @param data 
+ * @return * Insert 
+ */
 int tree_insert(Tree *tree, int data);
 
 // Remove some data from the tree