diff --git a/src/applications/metamta/management/PhabricatorMailManagementShowOutboundWorkflow.php b/src/applications/metamta/management/PhabricatorMailManagementShowOutboundWorkflow.php
--- a/src/applications/metamta/management/PhabricatorMailManagementShowOutboundWorkflow.php
+++ b/src/applications/metamta/management/PhabricatorMailManagementShowOutboundWorkflow.php
@@ -127,9 +127,10 @@
           $info[] = '  '.coalesce($actor->getName(), $actor->getPHID());
         } else {
           $info[] = '! '.coalesce($actor->getName(), $actor->getPHID());
-          foreach ($actor->getUndeliverableReasons() as $reason) {
-            $info[] = '    - '.$reason;
-          }
+        }
+        foreach ($actor->getDeliverabilityReasons() as $reason) {
+          $desc = PhabricatorMetaMTAActor::getReasonDescription($reason);
+          $info[] = '    - '.$desc;
         }
       }
 
diff --git a/src/applications/metamta/query/PhabricatorMetaMTAActor.php b/src/applications/metamta/query/PhabricatorMetaMTAActor.php
--- a/src/applications/metamta/query/PhabricatorMetaMTAActor.php
+++ b/src/applications/metamta/query/PhabricatorMetaMTAActor.php
@@ -2,9 +2,25 @@
 
 final class PhabricatorMetaMTAActor {
 
+  const STATUS_DELIVERABLE = 'deliverable';
+  const STATUS_UNDELIVERABLE = 'undeliverable';
+
+  const REASON_UNLOADABLE = 'unloadable';
+  const REASON_UNMAILABLE = 'unmailable';
+  const REASON_NO_ADDRESS = 'noaddress';
+  const REASON_DISABLED = 'disabled';
+  const REASON_MAIL_DISABLED = 'maildisabled';
+  const REASON_EXTERNAL_TYPE = 'exernaltype';
+  const REASON_RESPONSE = 'response';
+  const REASON_SELF = 'self';
+  const REASON_MAILTAGS = 'mailtags';
+  const REASON_BOT = 'bot';
+  const REASON_FORCE = 'force';
+
   private $phid;
   private $emailAddress;
   private $name;
+  private $status = self::STATUS_DELIVERABLE;
   private $reasons = array();
 
   public function setName($name) {
@@ -36,15 +52,66 @@
 
   public function setUndeliverable($reason) {
     $this->reasons[] = $reason;
+    $this->status = self::STATUS_UNDELIVERABLE;
+    return $this;
+  }
+
+  public function setDeliverable($reason) {
+    $this->reasons[] = $reason;
+    $this->status = self::STATUS_DELIVERABLE;
     return $this;
   }
 
   public function isDeliverable() {
-    return empty($this->reasons);
+    return ($this->status === self::STATUS_DELIVERABLE);
   }
 
-  public function getUndeliverableReasons() {
+  public function getDeliverabilityReasons() {
     return $this->reasons;
   }
 
+  public static function getReasonDescription($reason) {
+    $descriptions = array(
+      self::REASON_DISABLED => pht(
+        'This user is disabled; disabled users do not receive mail.'),
+      self::REASON_BOT => pht(
+        'This user is a bot; bot accounts do not receive mail.'),
+      self::REASON_NO_ADDRESS => pht(
+        'Unable to load an email address for this PHID.'),
+      self::REASON_EXTERNAL_TYPE => pht(
+        'Only external accounts of type "email" are deliverable; this '.
+        'account has a different type.'),
+      self::REASON_UNMAILABLE => pht(
+        'This PHID type does not correspond to a mailable object.'),
+      self::REASON_RESPONSE => pht(
+        'This message is a response to another email message, and this '.
+        'recipient received the original email message, so we are not '.
+        'sending them this substantially similar message (for example, '.
+        'the sender used "Reply All" instead of "Reply" in response to '.
+        'mail from Phabricator).'),
+      self::REASON_SELF => pht(
+        'This recipient is the user whose actions caused delivery of '.
+        'this message, but they have set preferences so they do not '.
+        'receive mail about their own actions (Settings > Email '.
+        'Preferences > Self Actions).'),
+      self::REASON_MAIL_DISABLED => pht(
+        'This recipient has disabled all email notifications '.
+        '(Settings > Email Preferences > Email Notifications).'),
+      self::REASON_MAILTAGS => pht(
+        'This mail has tags which control which users receive it, and '.
+        'this recipient has not elected to receive mail with any of '.
+        'the tags on this message (Settings > Email Preferences).'),
+      self::REASON_UNLOADABLE => pht(
+        'Unable to load user record for this PHID.'),
+      self::REASON_FORCE => pht(
+        'Delivery of this mail is forced and ignores deliver preferences. '.
+        'Mail which uses forced delivery is usually related to account '.
+        'management or authentication. For example, password reset email '.
+        'ignores mail preferences.'),
+    );
+
+    return idx($descriptions, $reason, pht('Unknown Reason ("%s")', $reason));
+  }
+
+
 }
diff --git a/src/applications/metamta/query/PhabricatorMetaMTAActorQuery.php b/src/applications/metamta/query/PhabricatorMetaMTAActorQuery.php
--- a/src/applications/metamta/query/PhabricatorMetaMTAActorQuery.php
+++ b/src/applications/metamta/query/PhabricatorMetaMTAActorQuery.php
@@ -70,17 +70,14 @@
 
       $user = idx($users, $phid);
       if (!$user) {
-        $actor->setUndeliverable(
-          pht('Unable to load user record for this PHID.'));
+        $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_UNLOADABLE);
       } else {
         $actor->setName($this->getUserName($user));
         if ($user->getIsDisabled()) {
-          $actor->setUndeliverable(
-            pht('This user is disabled; disabled users do not receive mail.'));
+          $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_DISABLED);
         }
         if ($user->getIsSystemAgent()) {
-          $actor->setUndeliverable(
-            pht('This user is a bot; bot accounts do not receive mail.'));
+          $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_BOT);
         }
 
         // NOTE: We do send email to unapproved users, and to unverified users,
@@ -91,8 +88,7 @@
 
       $email = idx($emails, $phid);
       if (!$email) {
-        $actor->setUndeliverable(
-          pht('Unable to load email record for this PHID.'));
+        $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_NO_ADDRESS);
       } else {
         $actor->setEmailAddress($email->getAddress());
       }
@@ -113,18 +109,14 @@
 
       $xuser = idx($xusers, $phid);
       if (!$xuser) {
-        $actor->setUndeliverable(
-          pht('Unable to load external user record for this PHID.'));
+        $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_UNLOADABLE);
         continue;
       }
 
       $actor->setName($xuser->getDisplayName());
 
       if ($xuser->getAccountType() != 'email') {
-        $actor->setUndeliverable(
-          pht(
-            'Only external accounts of type "email" are deliverable; this '.
-            'account has a different type.'));
+        $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_EXTERNAL_TYPE);
         continue;
       }
 
@@ -146,9 +138,7 @@
 
       $list = idx($lists, $phid);
       if (!$list) {
-        $actor->setUndeliverable(
-          pht(
-            'Unable to load mailing list record for this PHID.'));
+        $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_UNLOADABLE);
         continue;
       }
 
@@ -160,7 +150,7 @@
   private function loadUnknownActors(array $actors, array $phids) {
     foreach ($phids as $phid) {
       $actor = $actors[$phid];
-      $actor->setUndeliverable(pht('This PHID type is not mailable.'));
+      $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_UNMAILABLE);
     }
   }
 
diff --git a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
--- a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
+++ b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
@@ -852,6 +852,9 @@
 
     if ($this->getForceDelivery()) {
       // If we're forcing delivery, skip all the opt-out checks.
+      foreach ($actors as $actor) {
+        $actor->setDeliverable(PhabricatorMetaMTAActor::REASON_FORCE);
+      }
       return $actors;
     }
 
@@ -861,13 +864,7 @@
       if (!$actor) {
         continue;
       }
-      $actor->setUndeliverable(
-        pht(
-          'This message is a response to another email message, and this '.
-          'recipient received the original email message, so we are not '.
-          'sending them this substantially similar message (for example, '.
-          'the sender used "Reply All" instead of "Reply" in response to '.
-          'mail from Phabricator).'));
+      $actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_RESPONSE);
     }
 
     // Exclude the actor if their preferences are set.
@@ -885,12 +882,7 @@
           ->loadPreferences()
           ->getPreference($pref_key);
         if ($exclude_self) {
-          $from_actor->setUndeliverable(
-            pht(
-              'This recipient is the user whose actions caused delivery of '.
-              'this message, but they have set preferences so they do not '.
-              'receive mail about their own actions (Settings > Email '.
-              'Preferences > Self Actions).'));
+          $from_actor->setUndeliverable(PhabricatorMetaMTAActor::REASON_SELF);
         }
       }
     }
@@ -907,9 +899,7 @@
         false);
       if ($exclude) {
         $actors[$phid]->setUndeliverable(
-          pht(
-            'This recipient has disabled all email notifications '.
-            '(Settings > Email Preferences > Email Notifications).'));
+          PhabricatorMetaMTAActor::REASON_MAIL_DISABLED);
       }
     }
 
@@ -937,10 +927,7 @@
 
         if (!$send) {
           $actors[$phid]->setUndeliverable(
-            pht(
-              'This mail has tags which control which users receive it, and '.
-              'this recipient has not elected to receive mail with any of '.
-              'the tags on this message (Settings > Email Preferences).'));
+            PhabricatorMetaMTAActor::REASON_MAILTAGS);
         }
       }
     }