diff --git a/src/Utils/BuildClientSchema.php b/src/Utils/BuildClientSchema.php
index 99e8988ee..060f52324 100644
--- a/src/Utils/BuildClientSchema.php
+++ b/src/Utils/BuildClientSchema.php
@@ -489,7 +489,7 @@ public function buildDirective(array $directive) : Directive
             'name' => $directive['name'],
             'description' => $directive['description'],
             'args' => $this->buildInputValueDefMap($directive['args']),
-            'isRepeatable' => $directive['isRepeatable'],
+            'isRepeatable' => $directive['isRepeatable'] ?? false,
             'locations' => $directive['locations'],
         ]);
     }