diff --git a/src/resources/chat/completions/completions.ts b/src/resources/chat/completions/completions.ts
index 3ca1365f7..e18ad91a5 100644
--- a/src/resources/chat/completions/completions.ts
+++ b/src/resources/chat/completions/completions.ts
@@ -278,6 +278,14 @@ export interface ChatCompletion {
    */
   object: 'chat.completion';
 
+  /**
+   * Developer-defined metadata attached to the completion.
+   *
+   * This is commonly present on stored completions (e.g. via `retrieve`/`list`) and
+   * may be omitted in immediate `create` responses.
+   */
+  metadata?: Shared.Metadata | null;
+
   /**
    * Specifies the processing type used for serving the request.
    *