### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

When I use latest codex cli connect to LiteLLM to NIM nemotron-3-ultra-550b-a55b, I got the following exception, I have set on Codex config "disable_tools=true", also set "drop_params=true" on LiteLLM config.

drop_params strips unrecognized top-level parameters, if the structural error is deeply nested inside the tools array itself, it still caused this error. the fix maybe need strip all "namespace" to "function" or remove it

### Steps to Reproduce

1. in LLM Config.toml setup the nvidia nim model nemotron-3-ultra-550b-a55b 2. Open Codex 3. Exception Occur in Codex CLI terminal A bug happened! {"error":{"message":"litellm.BadRequestError: Nvidia_nimException - unknown variant `namespace`, expected `function`. Received Model Group=nemotron-3-ultra-550b-a55b-nvidia\nAvailable Model Group Fallbacks=['nemotron-3-super-120b-a12b-nvidia']\nError doing the fallback: litellm.BadRequestError: Nvidia_nimException - unknown variant `namespace`, expected `function`. Received Model Group=nemotron-3-super-120b-a12b-nvidia\nAvailable Model Group Fallba…