There is no Hermes-specific remote config endpoint.
Select the protocol explicitly
Hermes custom endpoints default tochat_completions, which uses /external/v1/chat/completions and Chat-style nested tool definitions/results. Keep that default for a generic Compose provider unless your Hermes configuration explicitly selects its Responses transport.
When api_mode: codex_responses is explicitly configured, point it at the same external base URL and verify that the selected Hermes version sends standard /responses items. Compose’s route accepts flat Responses tools, interleaved function calls, and multiple function_call_output items. Do not mix Chat tool messages with Responses items in one turn.