diff --git a/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php
index 1153f82a34..27b8276c85 100644
--- a/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php
+++ b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php
@@ -7,6 +7,7 @@ final class PhabricatorCustomFieldEditField
   private $httpParameterType;
   private $conduitParameterType;
   private $bulkParameterType;
+  private $commentAction;
 
   public function setCustomField(PhabricatorCustomField $custom_field) {
     $this->customField = $custom_field;
@@ -47,6 +48,16 @@ final class PhabricatorCustomFieldEditField
     return $this->bulkParameterType;
   }
 
+  public function setCustomFieldCommentAction(
+    PhabricatorEditEngineCommentAction $comment_action) {
+    $this->commentAction = $comment_action;
+    return $this;
+  }
+
+  public function getCustomFieldCommentAction() {
+    return $this->commentAction;
+  }
+
   protected function buildControl() {
     if ($this->getIsConduitOnly()) {
       return null;
@@ -77,6 +88,19 @@ final class PhabricatorCustomFieldEditField
     return $clone->getNewValueForApplicationTransactions();
   }
 
+  protected function getValueForCommentAction($value) {
+    $field = $this->getCustomField();
+    $clone = clone $field;
+    $clone->setValueFromApplicationTransactions($value);
+
+    // TODO: This is somewhat bogus because only StandardCustomFields
+    // implement a getFieldValue() method -- not all CustomFields. Today,
+    // only StandardCustomFields can ever actually generate a comment action
+    // so we never reach this method with other field types.
+
+    return $clone->getFieldValue();
+  }
+
   protected function getValueExistsInSubmit(AphrontRequest $request, $key) {
     return true;
   }
@@ -110,6 +134,16 @@ final class PhabricatorCustomFieldEditField
     return null;
   }
 
+  protected function newCommentAction() {
+    $action = $this->getCustomFieldCommentAction();
+
+    if ($action) {
+      return clone $action;
+    }
+
+    return null;
+  }
+
   protected function newConduitParameterType() {
     $type = $this->getCustomFieldConduitParameterType();
 
diff --git a/src/infrastructure/customfield/field/PhabricatorCustomField.php b/src/infrastructure/customfield/field/PhabricatorCustomField.php
index 818bf119ff..36db8f239b 100644
--- a/src/infrastructure/customfield/field/PhabricatorCustomField.php
+++ b/src/infrastructure/customfield/field/PhabricatorCustomField.php
@@ -1127,6 +1127,16 @@ abstract class PhabricatorCustomField extends Phobject {
       $field->setCustomFieldBulkParameterType($bulk_type);
     }
 
+    $comment_action = $this->getCommentAction();
+    if ($comment_action) {
+      $field
+        ->setCustomFieldCommentAction($comment_action)
+        ->setCommentActionLabel(
+          pht(
+            'Change %s',
+            $this->getFieldName()));
+    }
+
     return $field;
   }
 
@@ -1459,6 +1469,17 @@ abstract class PhabricatorCustomField extends Phobject {
     return null;
   }
 
+  public function getCommentAction() {
+    return $this->newCommentAction();
+  }
+
+  protected function newCommentAction() {
+    if ($this->proxy) {
+      return $this->proxy->newCommentAction();
+    }
+    return null;
+  }
+
 
 /* -(  Herald  )------------------------------------------------------------- */
 
diff --git a/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldTokenizer.php b/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldTokenizer.php
index 9bf59d41f6..3c5268d65b 100644
--- a/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldTokenizer.php
+++ b/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldTokenizer.php
@@ -143,4 +143,26 @@ abstract class PhabricatorStandardCustomFieldTokenizer
       ->setDatasource($datasource);
   }
 
+  protected function newCommentAction() {
+    $viewer = $this->getViewer();
+
+    $datasource = $this->getDatasource()
+      ->setViewer($viewer);
+
+    $action = id(new PhabricatorEditEngineTokenizerCommentAction())
+      ->setDatasource($datasource);
+
+    $limit = $this->getFieldConfigValue('limit');
+    if ($limit) {
+      $action->setLimit($limit);
+    }
+
+    $value = $this->getFieldValue();
+    if ($value !== null) {
+      $action->setInitialValue($value);
+    }
+
+    return $action;
+  }
+
 }