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
@@ -2840,6 +2840,7 @@
     'PhabricatorFerretFulltextEngineExtension' => 'applications/search/engineextension/PhabricatorFerretFulltextEngineExtension.php',
     'PhabricatorFerretInterface' => 'applications/search/ferret/PhabricatorFerretInterface.php',
     'PhabricatorFerretNgrams' => 'applications/search/ferret/PhabricatorFerretNgrams.php',
+    'PhabricatorFerretSearchEngineExtension' => 'applications/search/engineextension/PhabricatorFerretSearchEngineExtension.php',
     'PhabricatorFile' => 'applications/files/storage/PhabricatorFile.php',
     'PhabricatorFileAES256StorageFormat' => 'applications/files/format/PhabricatorFileAES256StorageFormat.php',
     'PhabricatorFileBundleLoader' => 'applications/files/query/PhabricatorFileBundleLoader.php',
@@ -8173,6 +8174,7 @@
     'PhabricatorFerretField' => 'PhabricatorSearchDAO',
     'PhabricatorFerretFulltextEngineExtension' => 'PhabricatorFulltextEngineExtension',
     'PhabricatorFerretNgrams' => 'PhabricatorSearchDAO',
+    'PhabricatorFerretSearchEngineExtension' => 'PhabricatorSearchEngineExtension',
     'PhabricatorFile' => array(
       'PhabricatorFileDAO',
       'PhabricatorApplicationTransactionInterface',
diff --git a/src/applications/maniphest/query/ManiphestTaskSearchEngine.php b/src/applications/maniphest/query/ManiphestTaskSearchEngine.php
--- a/src/applications/maniphest/query/ManiphestTaskSearchEngine.php
+++ b/src/applications/maniphest/query/ManiphestTaskSearchEngine.php
@@ -49,8 +49,6 @@
     $subtype_map = id(new ManiphestTask())->newEditEngineSubtypeMap();
     $hide_subtypes = (count($subtype_map) == 1);
 
-    $hide_ferret = !PhabricatorEnv::getEnvConfig('phabricator.show-prototypes');
-
     return array(
       id(new PhabricatorOwnersSearchField())
         ->setLabel(pht('Assigned To'))
@@ -91,10 +89,6 @@
       id(new PhabricatorSearchTextField())
         ->setLabel(pht('Contains Words'))
         ->setKey('fulltext'),
-      id(new PhabricatorSearchTextField())
-        ->setLabel(pht('Query (Prototype)'))
-        ->setKey('query')
-        ->setIsHidden($hide_ferret),
       id(new PhabricatorSearchThreeStateField())
         ->setLabel(pht('Open Parents'))
         ->setKey('hasParents')
@@ -150,7 +144,6 @@
       'statuses',
       'priorities',
       'subtypes',
-      'query',
       'fulltext',
       'hasParents',
       'hasSubtasks',
@@ -231,27 +224,6 @@
       $query->withFullTextSearch($map['fulltext']);
     }
 
-    if (strlen($map['query'])) {
-      $raw_query = $map['query'];
-
-      $compiler = id(new PhutilSearchQueryCompiler())
-        ->setEnableFunctions(true);
-
-      $raw_tokens = $compiler->newTokens($raw_query);
-
-      $fulltext_tokens = array();
-      foreach ($raw_tokens as $raw_token) {
-        $fulltext_token = id(new PhabricatorFulltextToken())
-          ->setToken($raw_token);
-
-        $fulltext_tokens[] = $fulltext_token;
-      }
-
-      $query->withFerretConstraint(
-        id(new ManiphestTask())->newFerretEngine(),
-        $fulltext_tokens);
-    }
-
     if ($map['parentIDs']) {
       $query->withParentTaskIDs($map['parentIDs']);
     }
diff --git a/src/applications/search/engineextension/PhabricatorFerretSearchEngineExtension.php b/src/applications/search/engineextension/PhabricatorFerretSearchEngineExtension.php
new file mode 100644
--- /dev/null
+++ b/src/applications/search/engineextension/PhabricatorFerretSearchEngineExtension.php
@@ -0,0 +1,70 @@
+<?php
+
+final class PhabricatorFerretSearchEngineExtension
+  extends PhabricatorSearchEngineExtension {
+
+  const EXTENSIONKEY = 'ferret';
+
+  public function isExtensionEnabled() {
+    return PhabricatorEnv::getEnvConfig('phabricator.show-prototypes');
+  }
+
+  public function getExtensionName() {
+    return pht('Fulltext Search');
+  }
+
+  public function getExtensionOrder() {
+    return 1000;
+  }
+
+  public function supportsObject($object) {
+    return ($object instanceof PhabricatorFerretInterface);
+  }
+
+  public function applyConstraintsToQuery(
+    $object,
+    $query,
+    PhabricatorSavedQuery $saved,
+    array $map) {
+
+    if (!strlen($map['query'])) {
+      return;
+    }
+
+    $engine = $object->newFerretEngine();
+
+    $raw_query = $map['query'];
+
+    $compiler = id(new PhutilSearchQueryCompiler())
+      ->setEnableFunctions(true);
+
+    $raw_tokens = $compiler->newTokens($raw_query);
+
+    $fulltext_tokens = array();
+    foreach ($raw_tokens as $raw_token) {
+      $fulltext_token = id(new PhabricatorFulltextToken())
+        ->setToken($raw_token);
+
+      $fulltext_tokens[] = $fulltext_token;
+    }
+
+    $query->withFerretConstraint($engine, $fulltext_tokens);
+  }
+
+  public function getSearchFields($object) {
+    $fields = array();
+
+    $fields[] = id(new PhabricatorSearchTextField())
+      ->setKey('query')
+      ->setLabel(pht('Query (Prototype)'))
+      ->setDescription(pht('Fulltext search.'));
+
+    return $fields;
+  }
+
+  public function getSearchAttachments($object) {
+    return array();
+  }
+
+
+}