diff --git a/src/Requests/CreateCompletionRequest.php b/src/Requests/CreateCompletionRequest.php
index 4b0d927..0f0d214 100644
--- a/src/Requests/CreateCompletionRequest.php
+++ b/src/Requests/CreateCompletionRequest.php
@@ -45,6 +45,10 @@ public function resolveEndpoint(): string
 
     public function defaultBody(): array
     {
+        if(! isset($metadata['user_id'])) {
+            $metadata['user_id'] = uniqid();
+        }
+
         return [
             'model' => 'claude-2',
             'prompt' => $this->prompt,