diff --git a/src/bot/commands/task.ts b/src/bot/commands/task.ts
index ead81be..9b43773 100644
--- a/src/bot/commands/task.ts
+++ b/src/bot/commands/task.ts
@@ -9,8 +9,15 @@ export function handleTaskCommand(body: string, sender: string, groupId: string,
       const [action, ...args] = command.split(' ');
       const description = args.join(' ');
 
-      const assignedUserMatch = description.match(/@\w+/);
+      // Extract WhatsApp mention (format: @<phone_number>)
+      const assignedUserMatch = description.match(/@\d+/);
       const assignedUser = assignedUserMatch ? assignedUserMatch[0] : null;
+      
+      // Validate phone number format
+      if (assignedUser && !/^@\d{8,}$/.test(assignedUser)) {
+        sendMessage(sender, 'Formato de mención inválido. Usa @ seguido del número de teléfono');
+        return;
+      }
 
       const dueDateMatch = description.match(/\d{4}-\d{2}-\d{2}/);
       const dueDate = dueDateMatch ? dueDateMatch[0] : null;
@@ -40,17 +47,23 @@ export function handleTaskCommand(body: string, sender: string, groupId: string,
           sendMessage(sender, `❌ Error al crear la tarea: ${error.message}`);
         }
       } else if (action === 'asignar') {
-        const taskId = args[0];
-        if (assignedUser) {
-          assignTask(parseInt(taskId), assignedUser);
-          sendMessage(sender, `Tarea ${taskId} asignada a ${assignedUser}`);
-        } else {
-          sendMessage(sender, 'Debes mencionar a un usuario para asignar la tarea. Ejemplo: /tarea asignar 1 @usuario');
+        try {
+          const taskId = validateTaskId(args[0]);
+          if (!assignedUser) {
+            throw new Error('Debes mencionar a un usuario para asignar la tarea. Ejemplo: /tarea asignar 1 @12345678');
+          }
+          
+          assignTask(taskId, assignedUser);
+          sendMessage(sender, `✅ Tarea ${taskId} asignada a ${assignedUser}`);
+        } catch (error) {
+          console.error('Error assigning task:', error);
+          sendMessage(sender, `❌ Error al asignar tarea: ${error.message}`);
         }
-      } else if (action === 'lista' || (!action && args.length === 1 && !isNaN(Number(args[0])))) {
+      } else if (action === 'lista' || (!action && args.length === 1)) {
         // Handle both /tarea lista 14 and /tarea 14
-        const taskId = args[0];
-        const task = getTaskById(parseInt(taskId));
+        try {
+          const taskId = validateTaskId(args[0]);
+          const task = getTaskById(taskId);
         
         if (!task) {
           sendMessage(sender, `Tarea ${taskId} no encontrada`);
diff --git a/src/services/taskService.ts b/src/services/taskService.ts
index 968d6c5..9ec8a23 100644
--- a/src/services/taskService.ts
+++ b/src/services/taskService.ts
@@ -58,9 +58,22 @@ export function getPendingTasks(assignedTo: string) {
 
 // Get task by ID
 export function getTaskById(taskId: number) {
+  if (!Number.isInteger(taskId) || taskId <= 0) {
+    throw new Error('ID de tarea inválido');
+  }
+
   const tasks = query(
     'SELECT * FROM tasks WHERE id = ?',
     [taskId]
   );
   return tasks[0] || null;
 }
+
+// Validate task ID from string input
+export function validateTaskId(taskIdStr: string): number {
+  const taskId = parseInt(taskIdStr);
+  if (isNaN(taskId) || taskId <= 0) {
+    throw new Error('ID de tarea inválido. Debe ser un número positivo');
+  }
+  return taskId;
+}