diff --git a/scripts/user/account_admin.php b/scripts/user/account_admin.php
--- a/scripts/user/account_admin.php
+++ b/scripts/user/account_admin.php
@@ -200,14 +200,17 @@
     $editor->updateUser($user, $verify_email);
   }
 
-  $editor->makeSystemAgentUser($user, $set_system_agent);
-
   $xactions = array();
   $xactions[] = id(new PhabricatorUserTransaction())
     ->setTransactionType(
       PhabricatorUserEmpowerTransaction::TRANSACTIONTYPE)
     ->setNewValue($set_admin);
 
+  $xactions[] = id(new PhabricatorUserTransaction())
+    ->setTransactionType(
+      PhabricatorUserSystemAgentTransaction::TRANSACTIONTYPE)
+    ->setNewValue($set_system_agent);
+
   $actor = PhabricatorUser::getOmnipotentUser();
   $content_source = PhabricatorContentSource::newForSource(
     PhabricatorConsoleContentSource::SOURCECONST);
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -4661,6 +4661,7 @@
     'PhabricatorUserIconField' => 'applications/people/customfield/PhabricatorUserIconField.php',
     'PhabricatorUserLog' => 'applications/people/storage/PhabricatorUserLog.php',
     'PhabricatorUserLogView' => 'applications/people/view/PhabricatorUserLogView.php',
+    'PhabricatorUserMailingListTransaction' => 'applications/people/xaction/PhabricatorUserMailingListTransaction.php',
     'PhabricatorUserMessageCountCacheType' => 'applications/people/cache/PhabricatorUserMessageCountCacheType.php',
     'PhabricatorUserNotificationCountCacheType' => 'applications/people/cache/PhabricatorUserNotificationCountCacheType.php',
     'PhabricatorUserNotifyTransaction' => 'applications/people/xaction/PhabricatorUserNotifyTransaction.php',
@@ -4680,6 +4681,7 @@
     'PhabricatorUserSchemaSpec' => 'applications/people/storage/PhabricatorUserSchemaSpec.php',
     'PhabricatorUserSinceField' => 'applications/people/customfield/PhabricatorUserSinceField.php',
     'PhabricatorUserStatusField' => 'applications/people/customfield/PhabricatorUserStatusField.php',
+    'PhabricatorUserSystemAgentTransaction' => 'applications/people/xaction/PhabricatorUserSystemAgentTransaction.php',
     'PhabricatorUserTestCase' => 'applications/people/storage/__tests__/PhabricatorUserTestCase.php',
     'PhabricatorUserTitleField' => 'applications/people/customfield/PhabricatorUserTitleField.php',
     'PhabricatorUserTransaction' => 'applications/people/storage/PhabricatorUserTransaction.php',
@@ -10773,6 +10775,7 @@
       'PhabricatorPolicyInterface',
     ),
     'PhabricatorUserLogView' => 'AphrontView',
+    'PhabricatorUserMailingListTransaction' => 'PhabricatorUserTransactionType',
     'PhabricatorUserMessageCountCacheType' => 'PhabricatorUserCacheType',
     'PhabricatorUserNotificationCountCacheType' => 'PhabricatorUserCacheType',
     'PhabricatorUserNotifyTransaction' => 'PhabricatorUserTransactionType',
@@ -10797,6 +10800,7 @@
     'PhabricatorUserSchemaSpec' => 'PhabricatorConfigSchemaSpec',
     'PhabricatorUserSinceField' => 'PhabricatorUserCustomField',
     'PhabricatorUserStatusField' => 'PhabricatorUserCustomField',
+    'PhabricatorUserSystemAgentTransaction' => 'PhabricatorUserTransactionType',
     'PhabricatorUserTestCase' => 'PhabricatorTestCase',
     'PhabricatorUserTitleField' => 'PhabricatorUserCustomField',
     'PhabricatorUserTransaction' => 'PhabricatorModularTransaction',
diff --git a/src/applications/people/controller/PhabricatorPeopleNewController.php b/src/applications/people/controller/PhabricatorPeopleNewController.php
--- a/src/applications/people/controller/PhabricatorPeopleNewController.php
+++ b/src/applications/people/controller/PhabricatorPeopleNewController.php
@@ -35,6 +35,7 @@
     $e_username = true;
     $e_realname = $require_real_name ? true : null;
     $e_email    = true;
+    $validation_exception = null;
     $errors = array();
 
     $welcome_checked = true;
@@ -78,7 +79,6 @@
 
       if (!$errors) {
         try {
-
           $email = id(new PhabricatorUserEmail())
             ->setAddress($new_email)
             ->setIsVerified(0);
@@ -95,17 +95,6 @@
             ->setActor($admin)
             ->createNewUser($user, $email);
 
-          if ($is_bot) {
-            id(new PhabricatorUserEditor())
-              ->setActor($admin)
-              ->makeSystemAgentUser($user, true);
-          }
-
-          if ($is_list) {
-            id(new PhabricatorUserEditor())
-              ->setActor($admin)
-              ->makeMailingListUser($user, true);
-          }
 
           if ($welcome_checked) {
             $welcome_engine = id(new PhabricatorPeopleWelcomeMailEngine())
@@ -116,9 +105,30 @@
             }
           }
 
-          $response = id(new AphrontRedirectResponse())
-            ->setURI('/p/'.$user->getUsername().'/');
-          return $response;
+          $xactions = array();
+          $xactions[] = id(new PhabricatorUserTransaction())
+            ->setTransactionType(
+              PhabricatorUserSystemAgentTransaction::TRANSACTIONTYPE)
+            ->setNewValue($is_bot);
+
+          $xactions[] = id(new PhabricatorUserTransaction())
+            ->setTransactionType(
+              PhabricatorUserMailingListTransaction::TRANSACTIONTYPE)
+            ->setNewValue($is_list);
+
+          $editor = id(new PhabricatorUserTransactionEditor())
+            ->setActor($admin)
+            ->setContentSourceFromRequest($request)
+            ->setContinueOnNoEffect(true)
+            ->setContinueOnMissingFields(true);
+
+          try {
+            $editor->applyTransactions($user, $xactions);
+            return id(new AphrontRedirectResponse())
+              ->setURI('/p/'.$user->getUsername().'/');
+          } catch (PhabricatorApplicationTransactionValidationException $ex) {
+            $validation_exception = $ex;
+          }
         } catch (AphrontDuplicateKeyQueryException $ex) {
           $errors[] = pht('Username and email must be unique.');
 
@@ -220,7 +230,7 @@
 
     $box = id(new PHUIObjectBoxView())
       ->setHeaderText($title)
-      ->setFormErrors($errors)
+      ->setValidationException($validation_exception)
       ->setBackground(PHUIObjectBoxView::WHITE_CONFIG)
       ->setForm($form);
 
diff --git a/src/applications/people/editor/PhabricatorUserEditor.php b/src/applications/people/editor/PhabricatorUserEditor.php
--- a/src/applications/people/editor/PhabricatorUserEditor.php
+++ b/src/applications/people/editor/PhabricatorUserEditor.php
@@ -129,84 +129,6 @@
   }
 
 
-/* -(  Editing Roles  )------------------------------------------------------ */
-
-  /**
-   * @task role
-   */
-  public function makeSystemAgentUser(PhabricatorUser $user, $system_agent) {
-    $actor = $this->requireActor();
-
-    if (!$user->getID()) {
-      throw new Exception(pht('User has not been created yet!'));
-    }
-
-    $user->openTransaction();
-      $user->beginWriteLocking();
-
-        $user->reload();
-        if ($user->getIsSystemAgent() == $system_agent) {
-          $user->endWriteLocking();
-          $user->killTransaction();
-          return $this;
-        }
-
-        $log = PhabricatorUserLog::initializeNewLog(
-          $actor,
-          $user->getPHID(),
-          PhabricatorUserLog::ACTION_SYSTEM_AGENT);
-        $log->setOldValue($user->getIsSystemAgent());
-        $log->setNewValue($system_agent);
-
-        $user->setIsSystemAgent((int)$system_agent);
-        $user->save();
-
-        $log->save();
-
-      $user->endWriteLocking();
-    $user->saveTransaction();
-
-    return $this;
-  }
-
-  /**
-   * @task role
-   */
-  public function makeMailingListUser(PhabricatorUser $user, $mailing_list) {
-    $actor = $this->requireActor();
-
-    if (!$user->getID()) {
-      throw new Exception(pht('User has not been created yet!'));
-    }
-
-    $user->openTransaction();
-      $user->beginWriteLocking();
-
-        $user->reload();
-        if ($user->getIsMailingList() == $mailing_list) {
-          $user->endWriteLocking();
-          $user->killTransaction();
-          return $this;
-        }
-
-        $log = PhabricatorUserLog::initializeNewLog(
-          $actor,
-          $user->getPHID(),
-          PhabricatorUserLog::ACTION_MAILING_LIST);
-        $log->setOldValue($user->getIsMailingList());
-        $log->setNewValue($mailing_list);
-
-        $user->setIsMailingList((int)$mailing_list);
-        $user->save();
-
-        $log->save();
-
-      $user->endWriteLocking();
-    $user->saveTransaction();
-
-    return $this;
-  }
-
 /* -(  Adding, Removing and Changing Email  )-------------------------------- */
 
 
diff --git a/src/applications/people/xaction/PhabricatorUserMailingListTransaction.php b/src/applications/people/xaction/PhabricatorUserMailingListTransaction.php
new file mode 100644
--- /dev/null
+++ b/src/applications/people/xaction/PhabricatorUserMailingListTransaction.php
@@ -0,0 +1,98 @@
+<?php
+
+final class PhabricatorUserMailingListTransaction
+  extends PhabricatorUserTransactionType {
+
+  const TRANSACTIONTYPE = 'user.mailing-list';
+
+  public function generateOldValue($object) {
+    return (bool)$object->getIsMailingList();
+  }
+
+  public function generateNewValue($object, $value) {
+    return (bool)$value;
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setIsMailingList((int)$value);
+  }
+
+  public function applyExternalEffects($object, $value) {
+    $user = $object;
+
+    $this->newUserLog(PhabricatorUserLog::ACTION_MAILING_LIST)
+      ->setOldValue($this->getOldValue())
+      ->setNewValue($value)
+      ->save();
+  }
+
+  public function validateTransactions($object, array $xactions) {
+    $user = $object;
+    $actor = $this->getActor();
+
+    $errors = array();
+
+    if ($object->getIsMailingList()) {
+      $errors[] = $this->newInvalidError(
+        pht('Users cannot be both bots and mailing lists.'));
+    }
+
+    foreach ($xactions as $xaction) {
+      $old = $xaction->getOldValue();
+      $new = $xaction->getNewValue();
+
+      if ($old === $new) {
+        continue;
+      }
+
+      $is_admin = $actor->getIsAdmin();
+      $is_omnipotent = $actor->isOmnipotent();
+
+      if (!$is_admin && !$is_omnipotent) {
+        $errors[] = $this->newInvalidError(
+          pht('You must be an administrator to turn users into mailing lists.'),
+          $xaction);
+      }
+    }
+
+    return $errors;
+  }
+
+  public function getTitle() {
+    $new = $this->getNewValue();
+    if ($new) {
+      return pht(
+        '%s transformed this user into a mailing list.',
+        $this->renderAuthor());
+    } else {
+      return pht(
+        '%s transformed this user from a mailing list into a regular user.',
+        $this->renderAuthor());
+    }
+  }
+
+  public function getTitleForFeed() {
+    $new = $this->getNewValue();
+    if ($new) {
+      return pht(
+        '%s transformed user %s into a mailing list.',
+        $this->renderAuthor(),
+        $this->renderObject());
+    } else {
+      return pht(
+        '%s transformed %s from a mailing list into a user.',
+        $this->renderAuthor(),
+        $this->renderObject());
+    }
+  }
+
+  public function getRequiredCapabilities(
+    $object,
+    PhabricatorApplicationTransaction $xaction) {
+
+    // Unlike normal user edits, making users into mailing lists requires admin
+    // permissions, which is enforced by validateTransactions().
+
+    return null;
+  }
+}
diff --git a/src/applications/people/xaction/PhabricatorUserSystemAgentTransaction.php b/src/applications/people/xaction/PhabricatorUserSystemAgentTransaction.php
new file mode 100644
--- /dev/null
+++ b/src/applications/people/xaction/PhabricatorUserSystemAgentTransaction.php
@@ -0,0 +1,98 @@
+<?php
+
+final class PhabricatorUserSystemAgentTransaction
+  extends PhabricatorUserTransactionType {
+
+  const TRANSACTIONTYPE = 'user.system-agent';
+
+  public function generateOldValue($object) {
+    return (bool)$object->getIsSystemAgent();
+  }
+
+  public function generateNewValue($object, $value) {
+    return (bool)$value;
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setIsSystemAgent((int)$value);
+  }
+
+  public function applyExternalEffects($object, $value) {
+    $user = $object;
+
+    $this->newUserLog(PhabricatorUserLog::ACTION_SYSTEM_AGENT)
+      ->setOldValue($this->getOldValue())
+      ->setNewValue($value)
+      ->save();
+  }
+
+  public function validateTransactions($object, array $xactions) {
+    $user = $object;
+    $actor = $this->getActor();
+
+    $errors = array();
+
+    if ($object->getIsMailingList()) {
+      $errors[] = $this->newInvalidError(
+        pht('Users cannot be both bots and mailing lists.'));
+    }
+
+    foreach ($xactions as $xaction) {
+      $old = $xaction->getOldValue();
+      $new = $xaction->getNewValue();
+
+      if ($old === $new) {
+        continue;
+      }
+
+      $is_admin = $actor->getIsAdmin();
+      $is_omnipotent = $actor->isOmnipotent();
+
+      if (!$is_admin && !$is_omnipotent) {
+        $errors[] = $this->newInvalidError(
+          pht('You must be an administrator to turn users into bots.'),
+          $xaction);
+      }
+    }
+
+    return $errors;
+  }
+
+  public function getTitle() {
+    $new = $this->getNewValue();
+    if ($new) {
+      return pht(
+        '%s transformed this user into a bot.',
+        $this->renderAuthor());
+    } else {
+      return pht(
+        '%s transformed this user from a bot into a regular user.',
+        $this->renderAuthor());
+    }
+  }
+
+  public function getTitleForFeed() {
+    $new = $this->getNewValue();
+    if ($new) {
+      return pht(
+        '%s transformed user %s into a bot.',
+        $this->renderAuthor(),
+        $this->renderObject());
+    } else {
+      return pht(
+        '%s transformed %s from a bot into a regular user.',
+        $this->renderAuthor(),
+        $this->renderObject());
+    }
+  }
+
+  public function getRequiredCapabilities(
+    $object,
+    PhabricatorApplicationTransaction $xaction) {
+
+    // Unlike normal user edits, making users into system agents requires admin
+    // permissions, which is enforced by validateTransactions().
+
+    return null;
+  }
+}