diff --git a/src/workflow/unit/ArcanistUnitWorkflow.php b/src/workflow/unit/ArcanistUnitWorkflow.php
index 10488905..bf976ec5 100644
--- a/src/workflow/unit/ArcanistUnitWorkflow.php
+++ b/src/workflow/unit/ArcanistUnitWorkflow.php
@@ -34,9 +34,10 @@ class ArcanistUnitWorkflow extends ArcanistBaseWorkflow {
 
   public function getCommandHelp() {
     return phutil_console_format(<<<EOTEXT
-      **unit**
+      **unit** [__paths__]
           Supports: git, svn
-          Run unit tests that cover local changes.
+          Run unit tests that cover specified paths. If no paths are specified,
+          unit tests covering all modified files will be run.
 EOTEXT
       );
   }