diff --git a/src/Commands/CallbackqueryCommand.php b/src/Commands/CallbackqueryCommand.php
new file mode 100644
index 0000000..f8fcb79
--- /dev/null
+++ b/src/Commands/CallbackqueryCommand.php
@@ -0,0 +1,25 @@
+<?php
+namespace Bot\Command\System;
+
+use Longman\TelegramBot\Commands\SystemCommand;
+use Longman\TelegramBot\Entities\ServerResponse;
+use Longman\TelegramBot\Request;
+
+class CallbackqueryCommand extends SystemCommand
+{
+    public function execute(): ServerResponse
+    {
+        try {
+            $callbackQuery = $this->getUpdate()->getCallbackQuery();
+            $originalSenderId = json_decode($callbackQuery->getData(), true)['sender_id'];
+            if ($originalSenderId === $callbackQuery->getFrom()?->getId()) {
+                return Request::deleteMessage([
+                    'chat_id'    => $callbackQuery->getMessage()->getChat()->getId(),
+                    'message_id' => $callbackQuery->getMessage()->getMessageId(),
+                ]);
+            }
+        } catch (\Exception $e) {
+        }
+        return Request::emptyResponse();
+    }
+}
\ No newline at end of file
diff --git a/src/Commands/DiagCommand.php b/src/Commands/DiagCommand.php
new file mode 100644
index 0000000..54235bb
--- /dev/null
+++ b/src/Commands/DiagCommand.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Longman\TelegramBot\Commands\UserCommands;
+
+use Longman\TelegramBot\Commands\UserCommand;
+use Longman\TelegramBot\Entities\ServerResponse;
+
+class DiagCommand extends UserCommand
+{
+    /** @var string */
+    protected $name = 'diag';
+
+    /** @var string */
+    protected $description = 'Show diagnosis information';
+
+    /** @var string */
+    protected $usage = '/diag';
+
+    /** @var string */
+    protected $version = '1.0.0';
+
+    public function execute(): ServerResponse
+    {
+        $fromId = $this->getMessage()?->getFrom()?->getId() ?? 'null';
+        $chatId = $this->getMessage()?->getChat()?->getId() ?? 'null';
+        return $this->replyToChat(
+            <<<END
+            Your user ID is `$fromId`.
+            This chat ID is `$chatId`.
+            END, [
+                'parse_mode' => 'markdown',
+                'disable_web_page_preview' => true,
+            ]);
+    }
+}
\ No newline at end of file
diff --git a/src/Commands/GenericmessageCommand.php b/src/Commands/GenericmessageCommand.php
index d784461..0a86c76 100755
--- a/src/Commands/GenericmessageCommand.php
+++ b/src/Commands/GenericmessageCommand.php
@@ -3,8 +3,11 @@
 namespace Longman\TelegramBot\Commands\SystemCommands;
 
 use Longman\TelegramBot\Commands\SystemCommand;
+use Longman\TelegramBot\Entities\InlineKeyboard;
+use Longman\TelegramBot\Entities\InlineKeyboardButton;
 use Longman\TelegramBot\Entities\ServerResponse;
 use Longman\TelegramBot\Request;
+
 // This class name is magic
 class GenericmessageCommand extends SystemCommand
 {
@@ -20,9 +23,9 @@ class GenericmessageCommand extends SystemCommand
         global $allowed_chat_ids;
         
         $message = $this->getMessage();
-        $chat_id = $message->getChat()->getId();
-        if(count($allowed_chat_ids) > 0 && !in_array($chat_id, $allowed_chat_ids)) {
-            return $this->replyToChat("Chat ID $chat_id not allowed");
+        $chatId = $message->getChat()->getId();
+        if(count($allowed_chat_ids) > 0 && !in_array($chatId, $allowed_chat_ids)) {
+            return $this->replyToChat("Chat ID $chatId not allowed");
         }
 
         $text = $message->getText(true);
@@ -44,12 +47,20 @@ class GenericmessageCommand extends SystemCommand
             }
         }
 
-        return $this->replyToChat(
-            "https://fxtwitter.com/$author/status/$tweetId$photoNo",
-            [
-                'reply_to_message_id' => $message->getMessageId(),
-                'disable_notification' => true,
-            ]
-        );
+        $data = [
+            'reply_to_message_id' => $message->getMessageId(),
+            'disable_notification' => true,
+        ];
+        if ($message->getFrom() !== null) {
+            $deleteButton = new InlineKeyboardButton([
+                'text' => '❌ Delete (original sender only)',
+                'callback_data' => json_encode([
+                    'sender_id' => $message->getFrom()?->getId(),
+                ]),
+            ]);
+            $data['reply_markup'] = new InlineKeyboard([$deleteButton]);
+        }
+
+        return $this->replyToChat("https://vxtwitter.com/$author/status/$tweetId$photoNo", $data);
     }
 }
\ No newline at end of file
diff --git a/src/Commands/HelpCommand.php b/src/Commands/HelpCommand.php
index 010c0e9..a17bf57 100644
--- a/src/Commands/HelpCommand.php
+++ b/src/Commands/HelpCommand.php
@@ -19,6 +19,8 @@ class HelpCommand extends UserCommand
     /** @var string */
     protected $version = '1.0.0';
 
+    protected $private_only = true;
+
     public function execute(): ServerResponse
     {
         return $this->replyToChat(