diff --git a/packages/toolbox-core/README.md b/packages/toolbox-core/README.md
index c4461df3..0c440d91 100644
--- a/packages/toolbox-core/README.md
+++ b/packages/toolbox-core/README.md
@@ -463,6 +463,11 @@ async with ToolboxClient("http://127.0.0.1:5000") as toolbox:
     print(result)
 ```
 
+> [!NOTE]
+> An auth token getter for a specific name (e.g., "GOOGLE_ID") will replace any
+> client header with the same name followed by "_token" (e.g.,
+> "GOOGLE_ID_token").
+
 ## Binding Parameter Values
 
 The SDK allows you to pre-set, or "bind", values for specific tool parameters
diff --git a/packages/toolbox-core/src/toolbox_core/tool.py b/packages/toolbox-core/src/toolbox_core/tool.py
index 1545ded4..1d3c25e7 100644
--- a/packages/toolbox-core/src/toolbox_core/tool.py
+++ b/packages/toolbox-core/src/toolbox_core/tool.py
@@ -276,12 +276,14 @@ async def __call__(self, *args: Any, **kwargs: Any) -> str:
 
         # create headers for auth services
         headers = {}
+        for client_header_name, client_header_val in self.__client_headers.items():
+            headers[client_header_name] = await resolve_value(client_header_val)
+
+        # In case of conflict, override the client header by the auth token getter
         for auth_service, token_getter in self.__auth_service_token_getters.items():
             headers[self.__get_auth_header(auth_service)] = await resolve_value(
                 token_getter
             )
-        for client_header_name, client_header_val in self.__client_headers.items():
-            headers[client_header_name] = await resolve_value(client_header_val)
 
         async with self.__session.post(
             self.__url,