When starting a Hume EVI chat, pass your own config ID if you need a instructions or tools; the defaults ship without them. You can update session settings like the voice mid-chat without reconnecting.

Context: Official Hume EVI TypeScript quickstart: documents the configuration gotchas. The config ID is optional; without one EVI uses the default configuration, which includes a preset voice and language model but no instructions and no tools. To customize behavior you must create your own configuration and pass its ID. Session settings, including the voice, can be updated mid-chat while preserving conversation context, so voice switching does not require reconnecting.