diff --git a/src/codex/_client.py b/src/codex/_client.py
index 9bdd5f0..2641513 100644
--- a/src/codex/_client.py
+++ b/src/codex/_client.py
@@ -154,11 +154,7 @@ def qs(self) -> Querystring:
     @property
     @override
     def auth_headers(self) -> dict[str, str]:
-        if self._authenticated_api_key:
-            return self._authenticated_api_key
-        if self._public_access_key:
-            return self._public_access_key
-        return {}
+        return {**self._authenticated_api_key, **self._public_access_key}
 
     @property
     def _authenticated_api_key(self) -> dict[str, str]:
@@ -386,11 +382,7 @@ def qs(self) -> Querystring:
     @property
     @override
     def auth_headers(self) -> dict[str, str]:
-        if self._authenticated_api_key:
-            return self._authenticated_api_key
-        if self._public_access_key:
-            return self._public_access_key
-        return {}
+        return {**self._authenticated_api_key, **self._public_access_key}
 
     @property
     def _authenticated_api_key(self) -> dict[str, str]: