Add User-Agent header

Author: anastasia-nesterenko

src/data_designer/engine/models/facade.py

@@ -64,6 +64,7 @@ def completion(self, messages: list[dict[str, str]], skip_usage_tracking: bool =
         )
         response = None
         try:
+            kwargs.setdefault("extra_headers", {})["User-Agent"] = "data-designer"
             response = self._router.completion(self.model_name, messages, **kwargs)
             logger.debug(
                 f"Received completion from model {self.model_name!r}",

tests/engine/models/test_facade.py

@@ -147,4 +147,9 @@ def mock_completion(model_name, messages, **kwargs):
     result = stub_model_facade.completion(messages, **kwargs)
 
     assert result == stub_expected_response
-    assert captured_kwargs == kwargs
+    # The completion method adds extra_headers with User-Agent to the kwargs
+    expected_kwargs = {
+        "extra_headers": {"User-Agent": "data-designer"},
+        **kwargs,
+    }
+    assert captured_kwargs == expected_kwargs