diff --git a/runtime/lib/webdav-scan-diagnostic.php b/runtime/lib/webdav-scan-diagnostic.php
new file mode 100644
index 0000000..3bc3cf5
--- /dev/null
+++ b/runtime/lib/webdav-scan-diagnostic.php
@@ -0,0 +1,152 @@
+#!/usr/bin/env php
+<?php
+if (PHP_SAPI !== 'cli')
+{
+  fwrite(STDERR, "CLI only\n");
+  exit(1);
+}
+
+$connection_id = 0;
+foreach ($argv as $arg)
+{
+  if (preg_match('/^--connection-id=(\d+)$/', $arg, $m)) $connection_id = (int)$m[1];
+}
+if ($connection_id < 1)
+{
+  fwrite(STDERR, "--connection-id fehlt oder ist ungueltig.\n");
+  exit(2);
+}
+
+$piwigo_root = realpath(dirname(__DIR__, 4));
+if ($piwigo_root === false)
+{
+  fwrite(STDERR, "Piwigo-Root wurde nicht gefunden.\n");
+  exit(3);
+}
+define('PHPWG_ROOT_PATH', rtrim($piwigo_root, DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR);
+
+$_SERVER['REMOTE_ADDR'] = '127.0.0.1';
+$_SERVER['SERVER_ADDR'] = '127.0.0.1';
+$_SERVER['SERVER_NAME'] = 'localhost';
+$_SERVER['HTTP_HOST'] = 'localhost';
+$_SERVER['SERVER_PORT'] = '80';
+$_SERVER['REQUEST_METHOD'] = 'GET';
+$_SERVER['REQUEST_URI'] = '/';
+$_SERVER['SCRIPT_NAME'] = '/plugins/bratonien_tools/runtime/lib/webdav-scan-diagnostic.php';
+$_SERVER['PHP_SELF'] = $_SERVER['SCRIPT_NAME'];
+$_SERVER['QUERY_STRING'] = '';
+$_SERVER['HTTP_USER_AGENT'] = 'Bratonien-WebDAV-Scan-Diagnostic/0.9.7.1.20';
+$_SERVER['HTTPS'] = 'off';
+
+try
+{
+  require_once(PHPWG_ROOT_PATH.'include/common.inc.php');
+  if (!defined('BRATONIEN_TOOLS_PATH')) throw new RuntimeException('Bratonien Tools ist nicht aktiv.');
+  require_once(BRATONIEN_TOOLS_PATH.'include/nc_connector.inc.php');
+
+  $connection = bratonien_tools_nc_connector_connection($connection_id, true);
+  if (!$connection || empty($connection['enabled'])) throw new RuntimeException('WebDAV-Verbindung wurde nicht gefunden oder ist deaktiviert.');
+  if (!bratonien_tools_nc_connector_is_webdav($connection)) throw new RuntimeException('Verbindung ist keine WebDAV-Placeholder-Verbindung.');
+
+  $config = isset($connection['config']) && is_array($connection['config']) ? $connection['config'] : array();
+  $state_dir = rtrim((string)($config['state_dir'] ?? ''), '/');
+  $gallery_root = rtrim((string)($config['parallel_gallery_root'] ?? ''), '/');
+  if ($state_dir === '') throw new RuntimeException('Connector-State-Verzeichnis fehlt.');
+  if ($gallery_root === '') throw new RuntimeException('Shadow-Tree-Pfad fehlt in der Connector-Konfiguration.');
+
+  $mapping_file = $state_dir.'/webdav-map.json';
+  if (!is_file($mapping_file) || !is_readable($mapping_file)) throw new RuntimeException('WebDAV-Mapping fehlt oder ist nicht lesbar: '.$mapping_file);
+  $mapping = json_decode((string)file_get_contents($mapping_file), true);
+  if (!is_array($mapping) || !isset($mapping['files']) || !is_array($mapping['files'])) throw new RuntimeException('WebDAV-Mapping ist ungueltig.');
+  if (!is_dir($gallery_root)) throw new RuntimeException('Shadow-Tree fehlt: '.$gallery_root);
+
+  $normalize = static function ($path) {
+    return rtrim(str_replace('\\', '/', (string)$path), '/');
+  };
+
+  $mapped_files = array();
+  foreach ($mapping['files'] as $path=>$meta)
+  {
+    if (!is_array($meta) || (string)($meta['kind'] ?? '') !== 'file') continue;
+    $mapped_files[$normalize($path)] = $meta;
+  }
+
+  $shadow_links = 0;
+  $matched = 0;
+  $broken = 0;
+  $unmapped = 0;
+  $duplicates = 0;
+  $seen = array();
+  $examples = array();
+
+  $iterator = new RecursiveIteratorIterator(
+    new RecursiveDirectoryIterator($gallery_root, FilesystemIterator::SKIP_DOTS),
+    RecursiveIteratorIterator::LEAVES_ONLY
+  );
+  foreach ($iterator as $item)
+  {
+    $shadow = $item->getPathname();
+    if (!is_link($shadow)) continue;
+    $shadow_links++;
+    $resolved = realpath($shadow);
+    if ($resolved === false || !is_file($resolved))
+    {
+      $broken++;
+      if (count($examples) < 8) $examples[] = array('state'=>'broken','shadow'=>$shadow);
+      continue;
+    }
+    $resolved = $normalize($resolved);
+    if (!isset($mapped_files[$resolved]))
+    {
+      $unmapped++;
+      if (count($examples) < 8) $examples[] = array('state'=>'unmapped','shadow'=>$shadow,'target'=>$resolved);
+      continue;
+    }
+    if (isset($seen[$resolved]))
+    {
+      $duplicates++;
+      if (count($examples) < 8) $examples[] = array('state'=>'duplicate','shadow'=>$shadow,'target'=>$resolved);
+      continue;
+    }
+    $seen[$resolved] = true;
+    $matched++;
+    if (count($examples) < 8)
+    {
+      $meta = $mapped_files[$resolved];
+      $examples[] = array(
+        'state'=>'matched',
+        'shadow'=>$shadow,
+        'target'=>$resolved,
+        'fileid'=>(int)($meta['fileid'] ?? 0),
+        'webdav_path'=>(string)($meta['webdav_path'] ?? ''),
+        'etag'=>(string)($meta['etag'] ?? ''),
+      );
+    }
+  }
+
+  $payload = array(
+    'ok'=>($shadow_links > 0 && $matched === $shadow_links && $broken === 0 && $unmapped === 0 && $duplicates === 0),
+    'connection_id'=>$connection_id,
+    'state_dir'=>$state_dir,
+    'gallery_root'=>$gallery_root,
+    'mapping_file'=>$mapping_file,
+    'mapping_files'=>count($mapped_files),
+    'shadow_links'=>$shadow_links,
+    'matched'=>$matched,
+    'broken'=>$broken,
+    'unmapped'=>$unmapped,
+    'duplicates'=>$duplicates,
+    'examples'=>$examples,
+  );
+  echo json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT)."\n";
+  exit($payload['ok'] ? 0 : 4);
+}
+catch (Throwable $e)
+{
+  echo json_encode(array(
+    'ok'=>false,
+    'connection_id'=>$connection_id,
+    'fatal'=>$e->getMessage(),
+  ), JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT)."\n";
+  exit(1);
+}