diff --git a/src/applications/passphrase/storage/PassphraseCredential.php b/src/applications/passphrase/storage/PassphraseCredential.php
--- a/src/applications/passphrase/storage/PassphraseCredential.php
+++ b/src/applications/passphrase/storage/PassphraseCredential.php
@@ -5,6 +5,7 @@
     PhabricatorApplicationTransactionInterface,
     PhabricatorPolicyInterface,
     PhabricatorFlaggableInterface,
+    PhabricatorMentionableInterface,
     PhabricatorSubscribableInterface,
     PhabricatorDestructibleInterface,
     PhabricatorSpacesInterface,