diff --git a/src/applications/diviner/renderer/DivinerDefaultRenderer.php b/src/applications/diviner/renderer/DivinerDefaultRenderer.php
index 459095864f..cbe7eae3b8 100644
--- a/src/applications/diviner/renderer/DivinerDefaultRenderer.php
+++ b/src/applications/diviner/renderer/DivinerDefaultRenderer.php
@@ -3,11 +3,124 @@
 final class DivinerDefaultRenderer extends DivinerRenderer {
 
   public function renderAtom(DivinerAtom $atom) {
-    return "ATOM: ".$atom->getType()." ".$atom->getName()."!";
+    $out = array(
+      $this->renderAtomTitle($atom),
+      $this->renderAtomProperties($atom),
+      $this->renderAtomDescription($atom),
+    );
+
+    return phutil_tag(
+      'div',
+      array(
+        'class' => 'diviner-atom',
+      ),
+      $out);
+  }
+
+  protected function renderAtomTitle(DivinerAtom $atom) {
+    $name = $this->renderAtomName($atom);
+    $type = $this->renderAtomType($atom);
+
+    return phutil_tag(
+      'h1',
+      array(
+        'class' => 'atom-title',
+      ),
+      array($name, ' ', $type));
+  }
+
+  protected function renderAtomName(DivinerAtom $atom) {
+    return phutil_tag(
+      'div',
+      array(
+        'class' => 'atom-name',
+      ),
+      $this->getAtomName($atom));
+  }
+
+  protected function getAtomName(DivinerAtom $atom) {
+    if ($atom->getDocblockMetaValue('title')) {
+      return $atom->getDocblockMetaValue('title');
+    }
+
+    return $atom->getName();
+  }
+
+  protected function renderAtomType(DivinerAtom $atom) {
+    return phutil_tag(
+      'div',
+      array(
+        'class' => 'atom-name',
+      ),
+      $this->getAtomType($atom));
+  }
+
+  protected function getAtomType(DivinerAtom $atom) {
+    return ucwords($atom->getType());
+  }
+
+  protected function renderAtomProperties(DivinerAtom $atom) {
+    $props = $this->getAtomProperties($atom);
+
+    $out = array();
+    foreach ($props as $prop) {
+      list($key, $value) = $prop;
+
+      $out[] = phutil_tag('dt', array(), $key);
+      $out[] = phutil_tag('dd', array(), $value);
+    }
+
+    return phutil_tag(
+      'dl',
+      array(
+        'class' => 'atom-properties',
+      ),
+      $out);
+  }
+
+  protected function getAtomProperties(DivinerAtom $atom) {
+    $properties = array();
+    $properties[] = array(
+      pht('Defined'),
+      $atom->getFile().':'.$atom->getLine(),
+    );
+
+    return $properties;
+  }
+
+  protected function renderAtomDescription(DivinerAtom $atom) {
+    $text = $this->getAtomDescription($atom);
+    $engine = $this->getBlockMarkupEngine();
+    return phutil_tag(
+      'div',
+      array(
+        'class' => 'atom-description',
+      ),
+      $engine->markupText($text));
+  }
+
+  protected function getAtomDescription(DivinerAtom $atom) {
+    return $atom->getDocblockText();
   }
 
   public function renderAtomSummary(DivinerAtom $atom) {
-    return "A lovely atom named ".$atom->getName();
+    $text = $this->getAtomSummary($atom);
+    $engine = $this->getInlineMarkupEngine();
+    return phutil_tag(
+      'span',
+      array(
+        'class' => 'atom-summary',
+      ),
+      $engine->markupText($text));
+  }
+
+  protected function getAtomSummary(DivinerAtom $atom) {
+    if ($atom->getDocblockMetaValue('summary')) {
+      return $atom->getDocblockMetaValue('summary');
+    }
+
+    $text = $this->getAtomDescription($atom);
+    return PhabricatorMarkupEngine::summarize($text);
   }
 
   public function renderAtomIndex(array $refs) {
@@ -17,16 +130,53 @@ final class DivinerDefaultRenderer extends DivinerRenderer {
 
     $out = array();
     foreach ($groups as $group_key => $refs) {
-      $out[] = '<h1>'.$group_key.'</h1>';
-      $out[] = '<ul>';
-      foreach ($refs as $ref) {
-        $out[] = '<li>'.$ref->getName().' - '.$ref->getSummary().'</li>';
-      }
-      $out[] = '</ul>';
-    }
-    $out = implode("\n", $out);
+      $out[] = phutil_tag(
+        'h1',
+        array(
+          'class' => 'atom-group-name',
+        ),
+        $this->getGroupName($group_key));
 
-    return $out;
+      $items = array();
+      foreach ($refs as $ref) {
+        $items[] = phutil_tag(
+          'li',
+          array(
+            'class' => 'atom-index-item',
+          ),
+          array(
+            $ref->getName(),
+            ' - ',
+            $ref->getSummary(),
+          ));
+      }
+
+      $out[] = phutil_tag(
+        'ul',
+        array(
+          'class' => 'atom-index-list',
+        ),
+        $items);
+    }
+
+    return phutil_tag(
+      'div',
+      array(
+        'class' => 'atom-index',
+      ),
+      $out);
+  }
+
+  protected function getGroupName($group_key) {
+    return $group_key;
+  }
+
+  protected function getBlockMarkupEngine() {
+    return PhabricatorMarkupEngine::newMarkupEngine(array());
+  }
+
+  protected function getInlineMarkupEngine() {
+    return $this->getBlockMarkupEngine();
   }
 
 
diff --git a/src/applications/diviner/workflow/DivinerGenerateWorkflow.php b/src/applications/diviner/workflow/DivinerGenerateWorkflow.php
index 573e1dcfa1..248bd85f40 100644
--- a/src/applications/diviner/workflow/DivinerGenerateWorkflow.php
+++ b/src/applications/diviner/workflow/DivinerGenerateWorkflow.php
@@ -392,6 +392,10 @@ final class DivinerGenerateWorkflow extends DivinerWorkflow {
     $atom_cache = $this->getAtomCache();
     $atom = $atom_cache->getAtom($node_hash);
 
+    if (!$atom) {
+      throw new Exception("No such atom with node hash '{$node_hash}'!");
+    }
+
     $ref = DivinerAtomRef::newFromDictionary($atom['ref']);
     return $ref->toHash();
   }