ai-agents-chat-template-overri-custom-chat-template-or-chat-template-kwargs-are-i-7c7f3bc7

THEN Modify the `get_system_message()` function in `vllm/entrypoints/openai/parser/harmony_utils.py` to accept and apply `chat_template_kwargs`, or patch the function at runtime to override the hardcoded defaults such as `model_identity`. Alternatively, pass custom values directly in the request payload rather than relying on `chat_template_kwargs`.

In `harmony_utils.py`, change `def get_system_message(model_identity='gpt-oss-20b', ...)` to accept `**kwargs` and replace the hardcoded string with values from `kwargs` when provided.