diff --git a/src/applications/search/management/PhabricatorSearchManagementNgramsWorkflow.php b/src/applications/search/management/PhabricatorSearchManagementNgramsWorkflow.php
index ef0d73fa3d..1a1124b4d8 100644
--- a/src/applications/search/management/PhabricatorSearchManagementNgramsWorkflow.php
+++ b/src/applications/search/management/PhabricatorSearchManagementNgramsWorkflow.php
@@ -1,139 +1,139 @@
 <?php
 
 final class PhabricatorSearchManagementNgramsWorkflow
   extends PhabricatorSearchManagementWorkflow {
 
   protected function didConstruct() {
     $this
       ->setName('ngrams')
       ->setSynopsis(
         pht(
           'Recompute common ngrams. This is an advanced workflow that '.
           'can harm search quality if used improperly.'))
       ->setArguments(
         array(
           array(
             'name' => 'reset',
             'help' => pht('Reset all common ngram records.'),
           ),
           array(
             'name' => 'threshold',
             'param' => 'threshold',
             'help' => pht(
               'Prune ngrams present in more than this fraction of '.
-              'documents.'),
+              'documents. Provide a value between 0.0 and 1.0.'),
           ),
         ));
   }
 
   public function execute(PhutilArgumentParser $args) {
     $min_documents = 4096;
 
     $is_reset = $args->getArg('reset');
     $threshold = $args->getArg('threshold');
 
     if ($is_reset && $threshold !== null) {
       throw new PhutilArgumentUsageException(
         pht('Specify either --reset or --threshold, not both.'));
     }
 
     if (!$is_reset && $threshold === null) {
       throw new PhutilArgumentUsageException(
         pht('Specify either --reset or --threshold.'));
     }
 
     if (!$is_reset) {
       if (!is_numeric($threshold)) {
         throw new PhutilArgumentUsageException(
           pht('Specify a numeric threshold between 0 and 1.'));
       }
 
       $threshold = (double)$threshold;
       if ($threshold <= 0 || $threshold >= 1) {
         throw new PhutilArgumentUsageException(
           pht('Threshold must be greater than 0.0 and less than 1.0.'));
       }
     }
 
     $all_objects = id(new PhutilClassMapQuery())
       ->setAncestorClass('PhabricatorFerretInterface')
       ->execute();
 
     foreach ($all_objects as $object) {
       $engine = $object->newFerretEngine();
       $conn = $object->establishConnection('w');
       $display_name = get_class($object);
 
       if ($is_reset) {
         echo tsprintf(
           "%s\n",
           pht(
             'Resetting common ngrams for "%s".',
             $display_name));
 
         queryfx(
           $conn,
           'DELETE FROM %T',
           $engine->getCommonNgramsTableName());
         continue;
       }
 
       $document_count = queryfx_one(
         $conn,
         'SELECT COUNT(*) N FROM %T',
         $engine->getDocumentTableName());
       $document_count = $document_count['N'];
 
       if ($document_count < $min_documents) {
         echo tsprintf(
           "%s\n",
           pht(
             'Too few documents of type "%s" for any ngrams to be common.',
             $display_name));
         continue;
       }
 
       $min_frequency = (int)ceil($document_count * $threshold);
       $common_ngrams = queryfx_all(
         $conn,
         'SELECT ngram, COUNT(*) N FROM %T
           GROUP BY ngram
           HAVING N >= %d',
         $engine->getNgramsTableName(),
         $min_frequency);
 
       if (!$common_ngrams) {
         echo tsprintf(
           "%s\n",
           pht(
             'No new common ngrams exist for "%s".',
             $display_name));
         continue;
       }
 
       $sql = array();
       foreach ($common_ngrams as $ngram) {
         $sql[] = qsprintf(
           $conn,
           '(%s, 1)',
           $ngram['ngram']);
       }
 
       foreach (PhabricatorLiskDAO::chunkSQL($sql) as $chunk) {
         queryfx(
           $conn,
           'INSERT IGNORE INTO %T (ngram, needsCollection)
             VALUES %Q',
           $engine->getCommonNgramsTableName(),
           $chunk);
       }
 
       echo tsprintf(
         "%s\n",
         pht(
           'Updated common ngrams for "%s".',
           $display_name));
     }
   }
 
 }