diff --git a/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php b/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php
--- a/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php
+++ b/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php
@@ -5,7 +5,7 @@
 
   private $viewer;
 
-  const KEY_EMBED_FILE_PHIDS = 'phabricator.embedded-file-phids';
+  const KEY_ATTACH_INTENT_FILE_PHIDS = 'files.attach-intent';
 
   protected function getObjectNamePrefix() {
     return 'F';
@@ -23,13 +23,44 @@
           PhabricatorFileThumbnailTransform::TRANSFORM_PREVIEW,
         ))
       ->execute();
+    $objects = mpull($objects, null, 'getID');
 
-    $phids_key = self::KEY_EMBED_FILE_PHIDS;
-    $phids = $engine->getTextMetadata($phids_key, array());
-    foreach (mpull($objects, 'getPHID') as $phid) {
-      $phids[] = $phid;
+
+    // Identify files embedded in the block with "attachment intent", i.e.
+    // those files which the user appears to want to attach to the object.
+    // Files referenced inside quoted blocks are not considered to have this
+    // attachment intent.
+
+    $metadata_key = self::KEY_RULE_OBJECT.'.'.$this->getObjectNamePrefix();
+    $metadata = $engine->getTextMetadata($metadata_key, array());
+
+    $attach_key = self::KEY_ATTACH_INTENT_FILE_PHIDS;
+    $attach_phids = $engine->getTextMetadata($attach_key, array());
+
+    foreach ($metadata as $item) {
+
+      // If this reference was inside a quoted block, don't count it. Quoting
+      // someone else doesn't establish an intent to attach a file.
+      $depth = idx($item, 'quote.depth');
+      if ($depth > 0) {
+        continue;
+      }
+
+      $id = $item['id'];
+      $file = idx($objects, $id);
+
+      if (!$file) {
+        continue;
+      }
+
+      $attach_phids[] = $file->getPHID();
     }
-    $engine->setTextMetadata($phids_key, $phids);
+
+    $attach_phids = array_fuse($attach_phids);
+    $attach_phids = array_keys($attach_phids);
+
+    $engine->setTextMetadata($attach_key, $attach_phids);
+
 
     return $objects;
   }
diff --git a/src/infrastructure/markup/PhabricatorMarkupEngine.php b/src/infrastructure/markup/PhabricatorMarkupEngine.php
--- a/src/infrastructure/markup/PhabricatorMarkupEngine.php
+++ b/src/infrastructure/markup/PhabricatorMarkupEngine.php
@@ -632,7 +632,7 @@
     foreach ($content_blocks as $content_block) {
       $engine->markupText($content_block);
       $phids = $engine->getTextMetadata(
-        PhabricatorEmbedFileRemarkupRule::KEY_EMBED_FILE_PHIDS,
+        PhabricatorEmbedFileRemarkupRule::KEY_ATTACH_INTENT_FILE_PHIDS,
         array());
       foreach ($phids as $phid) {
         $files[$phid] = $phid;
diff --git a/src/infrastructure/markup/blockrule/PhutilRemarkupBlockRule.php b/src/infrastructure/markup/blockrule/PhutilRemarkupBlockRule.php
--- a/src/infrastructure/markup/blockrule/PhutilRemarkupBlockRule.php
+++ b/src/infrastructure/markup/blockrule/PhutilRemarkupBlockRule.php
@@ -43,6 +43,14 @@
     return;
   }
 
+  public function willMarkupChildBlocks() {
+    return;
+  }
+
+  public function didMarkupChildBlocks() {
+    return;
+  }
+
   final public function setEngine(PhutilRemarkupEngine $engine) {
     $this->engine = $engine;
     $this->updateRules();
diff --git a/src/infrastructure/markup/blockrule/PhutilRemarkupQuotedBlockRule.php b/src/infrastructure/markup/blockrule/PhutilRemarkupQuotedBlockRule.php
--- a/src/infrastructure/markup/blockrule/PhutilRemarkupQuotedBlockRule.php
+++ b/src/infrastructure/markup/blockrule/PhutilRemarkupQuotedBlockRule.php
@@ -7,6 +7,22 @@
     return true;
   }
 
+  public function willMarkupChildBlocks() {
+    $engine = $this->getEngine();
+
+    $depth = $engine->getQuoteDepth();
+    $depth = $depth + 1;
+    $engine->setQuoteDepth($depth);
+  }
+
+  public function didMarkupChildBlocks() {
+    $engine = $this->getEngine();
+
+    $depth = $engine->getQuoteDepth();
+    $depth = $depth - 1;
+    $engine->setQuoteDepth($depth);
+  }
+
   final protected function normalizeQuotedBody($text) {
     $text = phutil_split_lines($text, true);
     foreach ($text as $key => $line) {
diff --git a/src/infrastructure/markup/remarkup/PhutilRemarkupEngine.php b/src/infrastructure/markup/remarkup/PhutilRemarkupEngine.php
--- a/src/infrastructure/markup/remarkup/PhutilRemarkupEngine.php
+++ b/src/infrastructure/markup/remarkup/PhutilRemarkupEngine.php
@@ -42,6 +42,14 @@
     return $this->mode & self::MODE_HTML_MAIL;
   }
 
+  public function getQuoteDepth() {
+    return $this->getConfig('runtime.quote.depth', 0);
+  }
+
+  public function setQuoteDepth($depth) {
+    return $this->setConfig('runtime.quote.depth', $depth);
+  }
+
   public function setBlockRules(array $rules) {
     assert_instances_of($rules, 'PhutilRemarkupBlockRule');
 
@@ -255,18 +263,24 @@
   }
 
   private function markupBlock(array $block) {
+    $rule = $block['rule'];
+
+    $rule->willMarkupChildBlocks();
+
     $children = array();
     foreach ($block['children'] as $child) {
       $children[] = $this->markupBlock($child);
     }
 
+    $rule->didMarkupChildBlocks();
+
     if ($children) {
       $children = $this->flattenOutput($children);
     } else {
       $children = null;
     }
 
-    return $block['rule']->markupText($block['text'], $children);
+    return $rule->markupText($block['text'], $children);
   }
 
   private function flattenOutput(array $output) {
diff --git a/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php b/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php
--- a/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php
+++ b/src/infrastructure/markup/rule/PhabricatorObjectRemarkupRule.php
@@ -318,6 +318,7 @@
       'id' => $matches[1],
       'options' => idx($matches, 2),
       'original' => $matches[0],
+      'quote.depth' => $engine->getQuoteDepth(),
     ));
   }
 
@@ -337,6 +338,7 @@
       'id' => $matches[1],
       'anchor' => idx($matches, 2),
       'original' => $matches[0],
+      'quote.depth' => $engine->getQuoteDepth(),
     ));
   }