diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 083ef473fa..a4d8a6b7a8 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -550,6 +550,7 @@ phutil_register_library_map(array(
     'DiffusionCommitHeraldFieldGroup' => 'applications/diffusion/herald/DiffusionCommitHeraldFieldGroup.php',
     'DiffusionCommitHookEngine' => 'applications/diffusion/engine/DiffusionCommitHookEngine.php',
     'DiffusionCommitHookRejectException' => 'applications/diffusion/exception/DiffusionCommitHookRejectException.php',
+    'DiffusionCommitMergeHeraldField' => 'applications/diffusion/herald/DiffusionCommitMergeHeraldField.php',
     'DiffusionCommitMessageHeraldField' => 'applications/diffusion/herald/DiffusionCommitMessageHeraldField.php',
     'DiffusionCommitPackageAuditHeraldField' => 'applications/diffusion/herald/DiffusionCommitPackageAuditHeraldField.php',
     'DiffusionCommitPackageHeraldField' => 'applications/diffusion/herald/DiffusionCommitPackageHeraldField.php',
@@ -4412,6 +4413,7 @@ phutil_register_library_map(array(
     'DiffusionCommitHeraldFieldGroup' => 'HeraldFieldGroup',
     'DiffusionCommitHookEngine' => 'Phobject',
     'DiffusionCommitHookRejectException' => 'Exception',
+    'DiffusionCommitMergeHeraldField' => 'DiffusionCommitHeraldField',
     'DiffusionCommitMessageHeraldField' => 'DiffusionCommitHeraldField',
     'DiffusionCommitPackageAuditHeraldField' => 'DiffusionCommitHeraldField',
     'DiffusionCommitPackageHeraldField' => 'DiffusionCommitHeraldField',
diff --git a/src/applications/diffusion/herald/DiffusionCommitMergeHeraldField.php b/src/applications/diffusion/herald/DiffusionCommitMergeHeraldField.php
new file mode 100644
index 0000000000..9fcfc985b0
--- /dev/null
+++ b/src/applications/diffusion/herald/DiffusionCommitMergeHeraldField.php
@@ -0,0 +1,20 @@
+<?php
+
+final class DiffusionCommitMergeHeraldField
+  extends DiffusionCommitHeraldField {
+
+  const FIELDCONST = 'diffusion.commit.merge';
+
+  public function getHeraldFieldName() {
+    return pht('Is merge commit');
+  }
+
+  public function getHeraldFieldValue($object) {
+    return $this->getAdapter()->loadIsMergeCommit();
+  }
+
+  protected function getHeraldFieldStandardType() {
+    return HeraldField::STANDARD_BOOL;
+  }
+
+}
diff --git a/src/applications/diffusion/herald/HeraldCommitAdapter.php b/src/applications/diffusion/herald/HeraldCommitAdapter.php
index 6530b72e6f..9baac6f2ad 100644
--- a/src/applications/diffusion/herald/HeraldCommitAdapter.php
+++ b/src/applications/diffusion/herald/HeraldCommitAdapter.php
@@ -209,18 +209,9 @@ final class HeraldCommitAdapter
   }
 
   private function loadCommitDiff() {
-    $drequest = DiffusionRequest::newFromDictionary(
-      array(
-        'user' => PhabricatorUser::getOmnipotentUser(),
-        'repository' => $this->repository,
-        'commit' => $this->commit->getCommitIdentifier(),
-      ));
-
     $byte_limit = self::getEnormousByteLimit();
 
-    $raw = DiffusionQuery::callConduitWithDiffusionRequest(
-      PhabricatorUser::getOmnipotentUser(),
-      $drequest,
+    $raw = $this->callConduit(
       'diffusion.rawdiffquery',
       array(
         'commit' => $this->commit->getCommitIdentifier(),
@@ -296,6 +287,32 @@ final class HeraldCommitAdapter
     return $result;
   }
 
+  public function loadIsMergeCommit() {
+    $parents = $this->callConduit(
+      'diffusion.commitparentsquery',
+      array(
+        'commit' => $this->getObject()->getCommitIdentifier(),
+      ));
+
+    return (count($parents) > 1);
+  }
+
+  private function callConduit($method, array $params) {
+    $viewer = PhabricatorUser::getOmnipotentUser();
+
+    $drequest = DiffusionRequest::newFromDictionary(
+      array(
+        'user' => $viewer,
+        'repository' => $this->repository,
+        'commit' => $this->commit->getCommitIdentifier(),
+      ));
+
+    return DiffusionQuery::callConduitWithDiffusionRequest(
+      $viewer,
+      $drequest,
+      $method,
+      $params);
+  }
 
 /* -(  HarbormasterBuildableAdapterInterface  )------------------------------ */