diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 40a99c4..6a24087 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        os: [ubuntu-latest]
+        os: [ubuntu-latest, macos-latest]
         php: [8.1, 8.2]
         symfony: [5.4.*, 6.3.*, 6.4.*, 7.0.*]
         dependency-version: [prefer-lowest, prefer-stable]
diff --git a/src/Resources/config/services.php b/src/Resources/config/services.php
index a4780b6..42ad5b5 100644
--- a/src/Resources/config/services.php
+++ b/src/Resources/config/services.php
@@ -17,6 +17,7 @@
         ->set(Factory::class)
         ->factory([OpenAI::class, 'factory'])
         ->call('withHttpClient', [service('openai.http_client')])
+        ->call('withHttpHeader', ['OpenAI-Beta', 'assistants=v1'])
 
         ->set(Client::class)
         ->factory([service(Factory::class), 'make'])