diff --git a/letta/server/server.py b/letta/server/server.py
index be188dac..79968f5e 100644
--- a/letta/server/server.py
+++ b/letta/server/server.py
@@ -530,7 +530,7 @@ class SyncServer(object):
         # update with model_settings
         if request.model_settings is not None:
             update_llm_config_params = request.model_settings._to_legacy_config_params()
-            request.llm_config.update(update_llm_config_params)
+            request.llm_config = request.llm_config.model_copy(update=update_llm_config_params)
 
         # Copy parallel_tool_calls from request to llm_config if provided
         if request.parallel_tool_calls is not None: