diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 4d143d0d44..108c73b044 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1356,6 +1356,7 @@ phutil_register_library_map(array(
     'HeraldConditionTranscript' => 'applications/herald/storage/transcript/HeraldConditionTranscript.php',
     'HeraldContentSourceField' => 'applications/herald/field/HeraldContentSourceField.php',
     'HeraldController' => 'applications/herald/controller/HeraldController.php',
+    'HeraldCoreStateReasons' => 'applications/herald/state/HeraldCoreStateReasons.php',
     'HeraldDAO' => 'applications/herald/storage/HeraldDAO.php',
     'HeraldDifferentialAdapter' => 'applications/differential/herald/HeraldDifferentialAdapter.php',
     'HeraldDifferentialDiffAdapter' => 'applications/differential/herald/HeraldDifferentialDiffAdapter.php',
@@ -6529,6 +6530,7 @@ phutil_register_library_map(array(
     'HeraldConditionTranscript' => 'Phobject',
     'HeraldContentSourceField' => 'HeraldField',
     'HeraldController' => 'PhabricatorController',
+    'HeraldCoreStateReasons' => 'HeraldStateReasons',
     'HeraldDAO' => 'PhabricatorLiskDAO',
     'HeraldDifferentialAdapter' => 'HeraldAdapter',
     'HeraldDifferentialDiffAdapter' => 'HeraldDifferentialAdapter',
diff --git a/src/applications/herald/state/HeraldCoreStateReasons.php b/src/applications/herald/state/HeraldCoreStateReasons.php
new file mode 100644
index 0000000000..7a033ff51e
--- /dev/null
+++ b/src/applications/herald/state/HeraldCoreStateReasons.php
@@ -0,0 +1,18 @@
+<?php
+
+final class HeraldCoreStateReasons
+  extends HeraldStateReasons {
+
+  const REASON_SILENT = 'core.silent';
+
+  public function explainReason($reason) {
+    $reasons = array(
+      self::REASON_SILENT => pht(
+        'This change applied silently, so mail and other notifications '.
+        'will not be sent.'),
+    );
+
+    return idx($reasons, $reason);
+  }
+
+}
diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
index b4ad4365a7..829e3ab43d 100644
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
@@ -68,7 +68,9 @@ abstract class PhabricatorApplicationTransactionEditor
   private $feedNotifyPHIDs = array();
   private $feedRelatedPHIDs = array();
   private $feedShouldPublish = false;
+  private $mailShouldSend = false;
   private $modularTypes;
+  private $silent;
 
   private $transactionQueue = array();
 
@@ -187,6 +189,15 @@ abstract class PhabricatorApplicationTransactionEditor
     return $this->isPreview;
   }
 
+  public function setIsSilent($silent) {
+    $this->silent = $silent;
+    return $this;
+  }
+
+  public function getIsSilent() {
+    return $this->silent;
+  }
+
   public function setIsInverseEdgeEditor($is_inverse_edge_editor) {
     $this->isInverseEdgeEditor = $is_inverse_edge_editor;
     return $this;
@@ -790,6 +801,10 @@ abstract class PhabricatorApplicationTransactionEditor
       $xaction->setObjectPHID($object->getPHID());
     }
 
+    if ($this->getIsSilent()) {
+      $xaction->setIsSilentTransaction(true);
+    }
+
     return $xaction;
   }
 
@@ -1136,15 +1151,22 @@ abstract class PhabricatorApplicationTransactionEditor
     // Editors need to pass into workers.
     $object = $this->willPublish($object, $xactions);
 
-    if ($this->shouldSendMail($object, $xactions)) {
-      $this->mailToPHIDs = $this->getMailTo($object);
-      $this->mailCCPHIDs = $this->getMailCC($object);
-    }
+    if (!$this->getIsSilent()) {
+      if ($this->shouldSendMail($object, $xactions)) {
+        $this->mailShouldSend = true;
+        $this->mailToPHIDs = $this->getMailTo($object);
+        $this->mailCCPHIDs = $this->getMailCC($object);
+      }
 
-    if ($this->shouldPublishFeedStory($object, $xactions)) {
-      $this->feedShouldPublish = true;
-      $this->feedRelatedPHIDs = $this->getFeedRelatedPHIDs($object, $xactions);
-      $this->feedNotifyPHIDs = $this->getFeedNotifyPHIDs($object, $xactions);
+      if ($this->shouldPublishFeedStory($object, $xactions)) {
+        $this->feedShouldPublish = true;
+        $this->feedRelatedPHIDs = $this->getFeedRelatedPHIDs(
+          $object,
+          $xactions);
+        $this->feedNotifyPHIDs = $this->getFeedNotifyPHIDs(
+          $object,
+          $xactions);
+      }
     }
 
     PhabricatorWorker::scheduleTask(
@@ -1186,7 +1208,7 @@ abstract class PhabricatorApplicationTransactionEditor
     $this->object = $object;
 
     $messages = array();
-    if ($this->shouldSendMail($object, $xactions)) {
+    if ($this->mailShouldSend) {
       $messages = $this->buildMail($object, $xactions);
     }
 
@@ -3138,6 +3160,16 @@ abstract class PhabricatorApplicationTransactionEditor
       $adapter->setApplicationEmail($this->getApplicationEmail());
     }
 
+    // If this editor is operating in silent mode, tell Herald that we aren't
+    // going to send any mail. This allows it to skip "the first time this
+    // rule matches, send me an email" rules which would otherwise match even
+    // though we aren't going to send any mail.
+    if ($this->getIsSilent()) {
+      $adapter->setForbiddenAction(
+        HeraldMailableState::STATECONST,
+        HeraldCoreStateReasons::REASON_SILENT);
+    }
+
     $xscript = HeraldEngine::loadAndApplyRules($adapter);
 
     $this->setHeraldAdapter($adapter);
@@ -3493,6 +3525,7 @@ abstract class PhabricatorApplicationTransactionEditor
       'feedNotifyPHIDs',
       'feedRelatedPHIDs',
       'feedShouldPublish',
+      'mailShouldSend',
     );
   }
 
@@ -3875,7 +3908,8 @@ abstract class PhabricatorApplicationTransactionEditor
       ->setActor($this->getActor())
       ->setContentSource($this->getContentSource())
       ->setContinueOnNoEffect($this->getContinueOnNoEffect())
-      ->setContinueOnMissingFields($this->getContinueOnMissingFields());
+      ->setContinueOnMissingFields($this->getContinueOnMissingFields())
+      ->setIsSilent($this->getIsSilent());
 
     if ($this->actingAsPHID !== null) {
       $editor->setActingAsPHID($this->actingAsPHID);
diff --git a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
index bf3c616df9..d49c3bf675 100644
--- a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
+++ b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
@@ -158,6 +158,14 @@ abstract class PhabricatorApplicationTransaction
     return (bool)$this->getMetadataValue('core.default', false);
   }
 
+  public function setIsSilentTransaction($silent) {
+    return $this->setMetadataValue('core.silent', $silent);
+  }
+
+  public function getIsSilentTransaction() {
+    return (bool)$this->getMetadataValue('core.silent', false);
+  }
+
   public function attachComment(
     PhabricatorApplicationTransactionComment $comment) {
     $this->comment = $comment;
@@ -1515,6 +1523,12 @@ abstract class PhabricatorApplicationTransaction
       if ($apart > (60 * 2)) {
         return false;
       }
+
+      // Don't group silent and nonsilent transactions together.
+      $is_silent = $this->getIsSilentTransaction();
+      if ($is_silent != $xaction->getIsSilentTransaction()) {
+        return false;
+      }
     }
 
     return true;
diff --git a/src/applications/transactions/view/PhabricatorApplicationTransactionView.php b/src/applications/transactions/view/PhabricatorApplicationTransactionView.php
index 0d427419d5..e10f5c008e 100644
--- a/src/applications/transactions/view/PhabricatorApplicationTransactionView.php
+++ b/src/applications/transactions/view/PhabricatorApplicationTransactionView.php
@@ -423,7 +423,8 @@ class PhabricatorApplicationTransactionView extends AphrontView {
       ->setUserHandle($xaction->getHandle($xaction->getAuthorPHID()))
       ->setIcon($xaction->getIcon())
       ->setColor($xaction->getColor())
-      ->setHideCommentOptions($this->getHideCommentOptions());
+      ->setHideCommentOptions($this->getHideCommentOptions())
+      ->setIsSilent($xaction->getIsSilentTransaction());
 
     list($token, $token_removed) = $xaction->getToken();
     if ($token) {
diff --git a/src/view/phui/PHUITimelineEventView.php b/src/view/phui/PHUITimelineEventView.php
index 51a0ea5aae..f07b40cb39 100644
--- a/src/view/phui/PHUITimelineEventView.php
+++ b/src/view/phui/PHUITimelineEventView.php
@@ -29,6 +29,7 @@ final class PHUITimelineEventView extends AphrontView {
   private $authorPHID;
   private $badges = array();
   private $pinboardItems = array();
+  private $isSilent;
 
   public function setAuthorPHID($author_phid) {
     $this->authorPHID = $author_phid;
@@ -177,6 +178,15 @@ final class PHUITimelineEventView extends AphrontView {
     return $this;
   }
 
+  public function setIsSilent($is_silent) {
+    $this->isSilent = $is_silent;
+    return $this;
+  }
+
+  public function getIsSilent() {
+    return $this->isSilent;
+  }
+
   public function setReallyMajorEvent($me) {
     $this->reallyMajorEvent = $me;
     return $this;