diff --git a/src/Wrapped/Parser.php b/src/Wrapped/Parser.php
index bec5747..590165f 100644
--- a/src/Wrapped/Parser.php
+++ b/src/Wrapped/Parser.php
@@ -154,9 +154,13 @@ final class Parser {
 				$data[$name] = $value;
 			}
 		}
-		$attributeStart = strpos($data['attributes'], '(');
+		$attributeStart = isset($data['attributes']) ? strpos($data['attributes'], '(') : false;
 		if ($attributeStart === false) {
-			throw new Exception("Malformed state response from server");
+			throw new Exception(sprintf(
+				"Malformed state response from server, attributes field %s: %s",
+				isset($data['attributes']) ? "'" . $data['attributes'] . "'" : 'missing',
+				implode("\n", $output)
+			));
 		}
 		return [
 			'mtime' => (int)strtotime($data['write_time']),