diff --git a/resources/celerity/map.php b/resources/celerity/map.php
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -80,7 +80,7 @@
     'rsrc/css/application/flag/flag.css' => 'bba8f811',
     'rsrc/css/application/harbormaster/harbormaster.css' => 'f491c9f4',
     'rsrc/css/application/herald/herald-test.css' => 'a52e323e',
-    'rsrc/css/application/herald/herald.css' => 'dc31f6e9',
+    'rsrc/css/application/herald/herald.css' => 'cd8d0134',
     'rsrc/css/application/maniphest/batch-editor.css' => 'b0f0b6d5',
     'rsrc/css/application/maniphest/report.css' => '9b9580b7',
     'rsrc/css/application/maniphest/task-edit.css' => 'fda62a9b',
@@ -416,7 +416,7 @@
     'rsrc/js/application/drydock/drydock-live-operation-status.js' => '901935ef',
     'rsrc/js/application/files/behavior-icon-composer.js' => '8499b6ab',
     'rsrc/js/application/files/behavior-launch-icon-composer.js' => '48086888',
-    'rsrc/js/application/herald/HeraldRuleEditor.js' => 'd6a7e717',
+    'rsrc/js/application/herald/HeraldRuleEditor.js' => '2dff5579',
     'rsrc/js/application/herald/PathTypeahead.js' => 'f7fc67ec',
     'rsrc/js/application/herald/herald-rule-editor.js' => '7ebaeed3',
     'rsrc/js/application/maniphest/behavior-batch-editor.js' => '782ab6e7',
@@ -578,8 +578,8 @@
     'font-lato' => 'c7ccd872',
     'global-drag-and-drop-css' => 'b556a948',
     'harbormaster-css' => 'f491c9f4',
-    'herald-css' => 'dc31f6e9',
-    'herald-rule-editor' => 'd6a7e717',
+    'herald-css' => 'cd8d0134',
+    'herald-rule-editor' => '2dff5579',
     'herald-test-css' => 'a52e323e',
     'inline-comment-summary-css' => 'f23d4e8f',
     'javelin-aphlict' => 'e1d4b11a',
@@ -1106,6 +1106,15 @@
       'javelin-install',
       'javelin-event',
     ),
+    '2dff5579' => array(
+      'multirow-row-manager',
+      'javelin-install',
+      'javelin-util',
+      'javelin-dom',
+      'javelin-stratcom',
+      'javelin-json',
+      'phabricator-prefab',
+    ),
     '2ee659ce' => array(
       'javelin-install',
     ),
@@ -2001,15 +2010,6 @@
       'javelin-dom',
       'javelin-stratcom',
     ),
-    'd6a7e717' => array(
-      'multirow-row-manager',
-      'javelin-install',
-      'javelin-util',
-      'javelin-dom',
-      'javelin-stratcom',
-      'javelin-json',
-      'phabricator-prefab',
-    ),
     'd7a74243' => array(
       'javelin-behavior',
       'javelin-stratcom',
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
@@ -1337,6 +1337,7 @@
     'HeraldApplyTranscript' => 'applications/herald/storage/transcript/HeraldApplyTranscript.php',
     'HeraldBasicFieldGroup' => 'applications/herald/field/HeraldBasicFieldGroup.php',
     'HeraldBuildableState' => 'applications/herald/state/HeraldBuildableState.php',
+    'HeraldCommentAction' => 'applications/herald/action/HeraldCommentAction.php',
     'HeraldCommitAdapter' => 'applications/diffusion/herald/HeraldCommitAdapter.php',
     'HeraldCondition' => 'applications/herald/storage/HeraldCondition.php',
     'HeraldConditionTranscript' => 'applications/herald/storage/transcript/HeraldConditionTranscript.php',
@@ -1378,6 +1379,7 @@
     'HeraldProjectsField' => 'applications/project/herald/HeraldProjectsField.php',
     'HeraldRecursiveConditionsException' => 'applications/herald/engine/exception/HeraldRecursiveConditionsException.php',
     'HeraldRelatedFieldGroup' => 'applications/herald/field/HeraldRelatedFieldGroup.php',
+    'HeraldRemarkupFieldValue' => 'applications/herald/value/HeraldRemarkupFieldValue.php',
     'HeraldRemarkupRule' => 'applications/herald/remarkup/HeraldRemarkupRule.php',
     'HeraldRepetitionPolicyConfig' => 'applications/herald/config/HeraldRepetitionPolicyConfig.php',
     'HeraldRule' => 'applications/herald/storage/HeraldRule.php',
@@ -6488,6 +6490,7 @@
     'HeraldApplyTranscript' => 'Phobject',
     'HeraldBasicFieldGroup' => 'HeraldFieldGroup',
     'HeraldBuildableState' => 'HeraldState',
+    'HeraldCommentAction' => 'HeraldAction',
     'HeraldCommitAdapter' => array(
       'HeraldAdapter',
       'HarbormasterBuildableAdapterInterface',
@@ -6535,6 +6538,7 @@
     'HeraldProjectsField' => 'HeraldField',
     'HeraldRecursiveConditionsException' => 'Exception',
     'HeraldRelatedFieldGroup' => 'HeraldFieldGroup',
+    'HeraldRemarkupFieldValue' => 'HeraldFieldValue',
     'HeraldRemarkupRule' => 'PhabricatorObjectRemarkupRule',
     'HeraldRepetitionPolicyConfig' => 'Phobject',
     'HeraldRule' => array(
diff --git a/src/applications/herald/action/HeraldAction.php b/src/applications/herald/action/HeraldAction.php
--- a/src/applications/herald/action/HeraldAction.php
+++ b/src/applications/herald/action/HeraldAction.php
@@ -9,6 +9,7 @@
   const STANDARD_NONE = 'standard.none';
   const STANDARD_PHID_LIST = 'standard.phid.list';
   const STANDARD_TEXT = 'standard.text';
+  const STANDARD_REMARKUP = 'standard.remarkup';
 
   const DO_STANDARD_EMPTY = 'do.standard.empty';
   const DO_STANDARD_NO_EFFECT = 'do.standard.no-effect';
@@ -60,6 +61,8 @@
         return new HeraldEmptyFieldValue();
       case self::STANDARD_TEXT:
         return new HeraldTextFieldValue();
+      case self::STANDARD_REMARKUP:
+        return new HeraldRemarkupFieldValue();
       case self::STANDARD_PHID_LIST:
         $tokenizer = id(new HeraldTokenizerFieldValue())
           ->setKey($this->getHeraldActionName())
diff --git a/src/applications/herald/action/HeraldCommentAction.php b/src/applications/herald/action/HeraldCommentAction.php
new file mode 100644
--- /dev/null
+++ b/src/applications/herald/action/HeraldCommentAction.php
@@ -0,0 +1,79 @@
+<?php
+
+final class HeraldCommentAction extends HeraldAction {
+
+  const ACTIONCONST = 'comment';
+  const DO_COMMENT = 'do.comment';
+
+  public function getHeraldActionName() {
+    return pht('Add comment');
+  }
+
+  public function getActionGroupKey() {
+    return HeraldUtilityActionGroup::ACTIONGROUPKEY;
+  }
+
+  public function supportsObject($object) {
+    if (!($object instanceof PhabricatorApplicationTransactionInterface)) {
+      return false;
+    }
+
+    $xaction = $object->getApplicationTransactionTemplate();
+    try {
+      $comment = $xaction->getApplicationTransactionCommentObject();
+      if (!$comment) {
+        return false;
+      }
+    } catch (PhutilMethodNotImplementedException $ex) {
+      return false;
+    }
+
+    return true;
+  }
+
+  public function supportsRuleType($rule_type) {
+    return ($rule_type != HeraldRuleTypeConfig::RULE_TYPE_PERSONAL);
+  }
+
+  public function applyEffect($object, HeraldEffect $effect) {
+    $adapter = $this->getAdapter();
+    $comment_text = $effect->getTarget();
+
+    $xaction = $adapter->newTransaction()
+      ->setTransactionType(PhabricatorTransactions::TYPE_COMMENT);
+
+    $comment = $xaction->getApplicationTransactionCommentObject()
+      ->setContent($comment_text);
+
+    $xaction->attachComment($comment);
+
+    $adapter->queueTransaction($xaction);
+
+    $this->logEffect(self::DO_COMMENT, $comment_text);
+  }
+
+  public function getHeraldActionStandardType() {
+    return self::STANDARD_REMARKUP;
+  }
+
+  protected function getActionEffectMap() {
+    return array(
+      self::DO_COMMENT => array(
+        'icon' => 'fa-comment',
+        'color' => 'blue',
+        'name' => pht('Added Comment'),
+      ),
+    );
+  }
+
+  public function renderActionDescription($value) {
+    $summary = PhabricatorMarkupEngine::summarize($value);
+    return pht('Add comment: %s', $summary);
+  }
+
+  protected function renderActionEffectDescription($type, $data) {
+    $summary = PhabricatorMarkupEngine::summarize($data);
+    return pht('Added a comment: %s', $summary);
+  }
+
+}
diff --git a/src/applications/herald/value/HeraldFieldValue.php b/src/applications/herald/value/HeraldFieldValue.php
--- a/src/applications/herald/value/HeraldFieldValue.php
+++ b/src/applications/herald/value/HeraldFieldValue.php
@@ -8,6 +8,7 @@
   const CONTROL_TEXT = 'herald.control.text';
   const CONTROL_SELECT = 'herald.control.select';
   const CONTROL_TOKENIZER = 'herald.control.tokenizer';
+  const CONTROL_REMARKUP = 'herald.control.remarkup';
 
   abstract public function getFieldValueKey();
   abstract public function getControlType();
diff --git a/src/applications/herald/value/HeraldRemarkupFieldValue.php b/src/applications/herald/value/HeraldRemarkupFieldValue.php
new file mode 100644
--- /dev/null
+++ b/src/applications/herald/value/HeraldRemarkupFieldValue.php
@@ -0,0 +1,22 @@
+<?php
+
+final class HeraldRemarkupFieldValue
+  extends HeraldFieldValue {
+
+  public function getFieldValueKey() {
+    return 'remarkup';
+  }
+
+  public function getControlType() {
+    return self::CONTROL_REMARKUP;
+  }
+
+  public function renderFieldValue($value) {
+    return $value;
+  }
+
+  public function renderEditorValue($value) {
+    return $value;
+  }
+
+}
diff --git a/webroot/rsrc/css/application/herald/herald.css b/webroot/rsrc/css/application/herald/herald.css
--- a/webroot/rsrc/css/application/herald/herald.css
+++ b/webroot/rsrc/css/application/herald/herald.css
@@ -37,6 +37,12 @@
   padding: 2px 4px;
 }
 
+.herald-action-table td textarea {
+  width: 95%;
+  height: 8em;
+  padding: 2px 4px;
+}
+
 .herald-action-table td.target {
   width: 100%;
 }
diff --git a/webroot/rsrc/js/application/herald/HeraldRuleEditor.js b/webroot/rsrc/js/application/herald/HeraldRuleEditor.js
--- a/webroot/rsrc/js/application/herald/HeraldRuleEditor.js
+++ b/webroot/rsrc/js/application/herald/HeraldRuleEditor.js
@@ -217,6 +217,11 @@
           get_fn = function() { return input.value; };
           set_fn = function(v) { input.value = v; };
           break;
+        case 'herald.control.remarkup':
+          input = JX.$N('textarea');
+          get_fn = function() { return input.value; };
+          set_fn = function(v) { input.value = v; };
+          break;
         case 'herald.control.select':
           var options;