diff --git a/src/validation.cc b/src/validation.cc
index 2c73902..cc7b703 100644
--- a/src/validation.cc
+++ b/src/validation.cc
@@ -9,48 +9,11 @@
 #include <algorithm>
 #include <string>
 
-/**
- * Check if a player belongs to a given room.
- *
- * @param player Pointer to the player object.
- * @param room Pointer to the room object.
- * @return `true` if the player belongs to the room, otherwise `false`.
- */
-bool player_belongs_to_room(const Player *player, const Room *room) {
-    return std::find(room->players.begin(), room->players.end(), *player) != room->players.end();
-}
-
-/**
- * Check if an action belongs to a given role.
- *
- * @param role Pointer to the role object.
- * @param action Pointer to the action object.
- * @return `true` if the action belongs to the role, otherwise `false`.
- */
-bool action_belongs_to_role(const Role *role, const Action *action) {
-    return std::find(role->actions.begin(), role->actions.end(), *action) != role->actions.end();
-}
-
-/**
- * Check if an action is allowed based on relevant events.
- *
- * @param action Pointer to the action object.
- * @param relevantEvents Pointer to the vector of relevant events.
- * @return `true` if the action is allowed, otherwise `false`.
- */
-bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events) {
-    bool allowed = false;  // Actions are disabled by default
-    std::sort(relevant_events->begin(), relevant_events->end());
-    for (const auto &event : *relevant_events) {
-        if (std::find(event.prohibits.begin(), event.prohibits.end(), *action) != event.prohibits.end()) {
-            allowed = false;
-        }
-        if (std::find(event.allows.begin(), event.allows.end(), *action) != event.allows.end()) {
-            allowed = true;
-        }
-    }
-    return allowed;
-}
+// These functions need to be declared to use the top-down rule and
+// make them as module private functions.
+bool player_belongs_to_room(const Player *player, const Room *room);
+bool action_belongs_to_role(const Role *role, const Action *action);
+bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events);
 
 /**
  * Validate if an action is valid for a player in a room based on related events.
@@ -98,6 +61,49 @@ ValidationStatus validate_action(
     return ValidationStatus::ActionValid;
 }
 
+/**
+ * Check if a player belongs to a given room.
+ *
+ * @param player Pointer to the player object.
+ * @param room Pointer to the room object.
+ * @return `true` if the player belongs to the room, otherwise `false`.
+ */
+bool player_belongs_to_room(const Player *player, const Room *room) {
+    return std::find(room->players.begin(), room->players.end(), *player) != room->players.end();
+}
+
+/**
+ * Check if an action belongs to a given role.
+ *
+ * @param role Pointer to the role object.
+ * @param action Pointer to the action object.
+ * @return `true` if the action belongs to the role, otherwise `false`.
+ */
+bool action_belongs_to_role(const Role *role, const Action *action) {
+    return std::find(role->actions.begin(), role->actions.end(), *action) != role->actions.end();
+}
+
+/**
+ * Check if an action is allowed based on relevant events.
+ *
+ * @param action Pointer to the action object.
+ * @param relevantEvents Pointer to the vector of relevant events.
+ * @return `true` if the action is allowed, otherwise `false`.
+ */
+bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events) {
+    bool allowed = false;  // Actions are disabled by default
+    std::sort(relevant_events->begin(), relevant_events->end());
+    for (const auto &event : *relevant_events) {
+        if (std::find(event.prohibits.begin(), event.prohibits.end(), *action) != event.prohibits.end()) {
+            allowed = false;
+        }
+        if (std::find(event.allows.begin(), event.allows.end(), *action) != event.allows.end()) {
+            allowed = true;
+        }
+    }
+    return allowed;
+}
+
 std::string ValidationStatusUtils::to_string(ValidationStatus status) {
     switch (status) {
         case ValidationStatus::PlayerNotInRoom: return "player not in room";