diff --git a/src/Changelog/ChangelogException.php b/src/Changelog/ChangelogException.php
index cc220d43..9ffb4f26 100644
--- a/src/Changelog/ChangelogException.php
+++ b/src/Changelog/ChangelogException.php
@@ -1,6 +1,6 @@
 <?php
 namespace Misuzu\Changelog;
 
-use Exception;
+use Misuzu\MisuzuException;
 
-class ChangelogException extends Exception {}
+class ChangelogException extends MisuzuException {}
diff --git a/src/Comments/CommentsException.php b/src/Comments/CommentsException.php
index cd7f45a0..eaccf53b 100644
--- a/src/Comments/CommentsException.php
+++ b/src/Comments/CommentsException.php
@@ -1,6 +1,6 @@
 <?php
 namespace Misuzu\Comments;
 
-use Exception;
+use Misuzu\MisuzuException;
 
-class CommentsException extends Exception {}
+class CommentsException extends MisuzuException {}
diff --git a/src/MisuzuException.php b/src/MisuzuException.php
new file mode 100644
index 00000000..5f1c4393
--- /dev/null
+++ b/src/MisuzuException.php
@@ -0,0 +1,6 @@
+<?php
+namespace Misuzu;
+
+use Exception;
+
+class MisuzuException extends Exception {}
diff --git a/src/News/NewsException.php b/src/News/NewsException.php
index aaa4c004..2a6b9775 100644
--- a/src/News/NewsException.php
+++ b/src/News/NewsException.php
@@ -1,6 +1,6 @@
 <?php
 namespace Misuzu\News;
 
-use Exception;
+use Misuzu\MisuzuException;
 
-class NewsException extends Exception {}
+class NewsException extends MisuzuException {}
diff --git a/src/Users/ChatToken.php b/src/Users/ChatToken.php
index bb4f855e..40a0fb6b 100644
--- a/src/Users/ChatToken.php
+++ b/src/Users/ChatToken.php
@@ -8,16 +8,10 @@ use RuntimeException;
 final class ChatToken {
     public const TOKEN_LIFETIME = 60 * 60 * 24 * 7;
 
-    public function hasUserId(): bool {
-        return isset($this->user_id);
-    }
     public function getUserId(): int {
         return $this->user_id ?? 0;
     }
 
-    public function hasToken(): bool {
-        return isset($this->token_string);
-    }
     public function getToken(): string {
         return $this->token_string ?? '';
     }
@@ -33,9 +27,6 @@ final class ChatToken {
     }
 
     public function delete(): void {
-        if(!$this->hasUserId() || !$this->hasToken())
-            return;
-
         DB::prepare('
             DELETE FROM `msz_user_chat_tokens`
             WHERE `user_id` = :user,
diff --git a/src/Users/UsersException.php b/src/Users/UsersException.php
index 15a6a2c9..d71b87ac 100644
--- a/src/Users/UsersException.php
+++ b/src/Users/UsersException.php
@@ -1,6 +1,6 @@
 <?php
 namespace Misuzu\Users;
 
-use Exception;
+use Misuzu\MisuzuException;
 
-class UsersException extends Exception {}
+class UsersException extends MisuzuException {}