diff --git a/openai-java-core/src/main/kotlin/com/openai/core/http/HttpResponse.kt b/openai-java-core/src/main/kotlin/com/openai/core/http/HttpResponse.kt
index 495acfd4a..6ceea355d 100644
--- a/openai-java-core/src/main/kotlin/com/openai/core/http/HttpResponse.kt
+++ b/openai-java-core/src/main/kotlin/com/openai/core/http/HttpResponse.kt
@@ -11,6 +11,10 @@ interface HttpResponse : AutoCloseable {
 
     fun headers(): Headers
 
+    /**
+     * Returns the value of the `x-request-id` header, or an empty [Optional] if there's no such
+     * header in the response.
+     */
     fun requestId(): Optional<String> =
         Optional.ofNullable(headers().values("x-request-id").firstOrNull())