diff --git a/src/parser/argument/PhutilArgumentParser.php b/src/parser/argument/PhutilArgumentParser.php
--- a/src/parser/argument/PhutilArgumentParser.php
+++ b/src/parser/argument/PhutilArgumentParser.php
@@ -627,6 +627,16 @@
     return $this;
   }
 
+  public function setWorkflows($workflows) {
+    $workflows = mpull($workflows, null, 'getName');
+    $this->workflows = $workflows;
+    return $this;
+  }
+
+  public function getWorkflows() {
+    return $this->workflows;
+  }
+
 
 /* -(  Command Help  )------------------------------------------------------- */
 
diff --git a/src/parser/argument/workflow/PhutilHelpArgumentWorkflow.php b/src/parser/argument/workflow/PhutilHelpArgumentWorkflow.php
--- a/src/parser/argument/workflow/PhutilHelpArgumentWorkflow.php
+++ b/src/parser/argument/workflow/PhutilHelpArgumentWorkflow.php
@@ -2,6 +2,17 @@
 
 final class PhutilHelpArgumentWorkflow extends PhutilArgumentWorkflow {
 
+  private $runtime;
+
+  public function setRuntime($runtime) {
+    $this->runtime = $runtime;
+    return $this;
+  }
+
+  public function getRuntime() {
+    return $this->runtime;
+  }
+
   protected function didConstruct() {
     $this->setName('help');
     $this->setExamples(<<<EOHELP
@@ -28,6 +39,45 @@
   public function execute(PhutilArgumentParser $args) {
     $with = $args->getArg('help-with-what');
 
+    $runtime = $this->getRuntime();
+    $toolset = $runtime->getToolset();
+    if ($toolset->getToolsetKey() === 'arc') {
+      $workflows = $args->getWorkflows();
+
+      $legacy = array();
+
+      $legacy[] = new ArcanistCloseRevisionWorkflow();
+      $legacy[] = new ArcanistCommitWorkflow();
+      $legacy[] = new ArcanistCoverWorkflow();
+      $legacy[] = new ArcanistDiffWorkflow();
+      $legacy[] = new ArcanistExportWorkflow();
+      $legacy[] = new ArcanistGetConfigWorkflow();
+      $legacy[] = new ArcanistSetConfigWorkflow();
+      $legacy[] = new ArcanistInstallCertificateWorkflow();
+      $legacy[] = new ArcanistLandWorkflow();
+      $legacy[] = new ArcanistLintersWorkflow();
+      $legacy[] = new ArcanistLintWorkflow();
+      $legacy[] = new ArcanistListWorkflow();
+      $legacy[] = new ArcanistPatchWorkflow();
+      $legacy[] = new ArcanistPasteWorkflow();
+      $legacy[] = new ArcanistTasksWorkflow();
+      $legacy[] = new ArcanistTodoWorkflow();
+      $legacy[] = new ArcanistUnitWorkflow();
+      $legacy[] = new ArcanistWhichWorkflow();
+
+      foreach ($legacy as $workflow) {
+        // If this workflow has been updated but not removed from the list
+        // above yet, just skip it.
+        if ($workflow instanceof ArcanistArcWorkflow) {
+          continue;
+        }
+
+        $workflows[] = $workflow->newLegacyPhutilWorkflow();
+      }
+
+      $args->setWorkflows($workflows);
+    }
+
     if (!$with) {
       $args->printHelpAndExit();
     } else {
diff --git a/src/runtime/ArcanistRuntime.php b/src/runtime/ArcanistRuntime.php
--- a/src/runtime/ArcanistRuntime.php
+++ b/src/runtime/ArcanistRuntime.php
@@ -9,6 +9,7 @@
   private $stack = array();
 
   private $viewer;
+  private $toolset;
   private $hardpointEngine;
   private $symbolEngine;
   private $conduitEngine;
@@ -107,6 +108,7 @@
     $config->validateConfiguration($this);
 
     $toolset = $this->newToolset($argv);
+    $this->setToolset($toolset);
 
     $args->parsePartial($toolset->getToolsetArguments());
 
@@ -118,13 +120,13 @@
 
     $phutil_workflows = array();
     foreach ($workflows as $key => $workflow) {
-      $phutil_workflows[$key] = $workflow->newPhutilWorkflow();
-
       $workflow
         ->setRuntime($this)
         ->setConfigurationEngine($config_engine)
         ->setConfigurationSourceList($config)
         ->setConduitEngine($conduit_engine);
+
+      $phutil_workflows[$key] = $workflow->newPhutilWorkflow();
     }
 
 
@@ -858,4 +860,13 @@
     return $this->conduitEngine;
   }
 
+  public function setToolset($toolset) {
+    $this->toolset = $toolset;
+    return $this;
+  }
+
+  public function getToolset() {
+    return $this->toolset;
+  }
+
 }
diff --git a/src/toolset/workflow/ArcanistHelpWorkflow.php b/src/toolset/workflow/ArcanistHelpWorkflow.php
--- a/src/toolset/workflow/ArcanistHelpWorkflow.php
+++ b/src/toolset/workflow/ArcanistHelpWorkflow.php
@@ -8,7 +8,8 @@
   }
 
   public function newPhutilWorkflow() {
-    return new PhutilHelpArgumentWorkflow();
+    return id(new PhutilHelpArgumentWorkflow())
+      ->setRuntime($this->getRuntime());
   }
 
   public function supportsToolset(ArcanistToolset $toolset) {
diff --git a/src/workflow/ArcanistWorkflow.php b/src/workflow/ArcanistWorkflow.php
--- a/src/workflow/ArcanistWorkflow.php
+++ b/src/workflow/ArcanistWorkflow.php
@@ -166,6 +166,47 @@
     return $phutil_workflow;
   }
 
+  final public function newLegacyPhutilWorkflow() {
+    $phutil_workflow = id(new ArcanistPhutilWorkflow())
+      ->setName($this->getWorkflowName());
+
+    $arguments = $this->getArguments();
+
+    $specs = array();
+    foreach ($arguments as $key => $argument) {
+      if ($key == '*') {
+        $key = $argument;
+        $argument = array(
+          'wildcard' => true,
+        );
+      }
+
+      unset($argument['paramtype']);
+      unset($argument['supports']);
+      unset($argument['nosupport']);
+      unset($argument['passthru']);
+      unset($argument['conflict']);
+
+      $spec = array(
+        'name' => $key,
+      ) + $argument;
+
+      $specs[] = $spec;
+    }
+
+    $phutil_workflow->setArguments($specs);
+
+    $synopses = $this->getCommandSynopses();
+    $phutil_workflow->setSynopsis($synopses);
+
+    $help = $this->getCommandHelp();
+    if (strlen($help)) {
+      $phutil_workflow->setHelp($help);
+    }
+
+    return $phutil_workflow;
+  }
+
   final protected function newWorkflowArgument($key) {
     return id(new ArcanistWorkflowArgument())
       ->setKey($key);