There is no universal expressive-mode switch in the agent TTS contract. Model options and expressive-audio-tag capabilities are separate. Voice publication and live expressive conversation behavior remain unavailable.
Choose an approach
An emotion option does not imply support for arbitrary tags. Pronunciation dictionaries and phoneme tags are also separate capabilities; review pronunciation when the issue is how a word sounds.
Prepare a controlled comparison
1
Write the intended delivery
Describe a concrete result, such as a calm pace while explaining a failed payment. Avoid instructions that pressure the listener or claim emotions the agent cannot know.
2
Check the selected model
Use Get available AI model to inspect its parameter schema and expressive-tag capability. Do not borrow tag syntax or option names from another model.
3
Save only supported settings
If using a model option, place it under
conversation_config.tts.options with the matching schema_id. Preserve the rest of the configuration in a server draft.4
Keep the listening result separate
Read back the requested settings, then record the listening comparison as pending until a supported speech path is available. A saved option cannot establish that the delivery sounds natural.
Frequently asked questions
Can I add arbitrary stage directions to the prompt?
Can I add arbitrary stage directions to the prompt?
Treat tone instructions as text. Do not assume bracketed directions become audio controls; an unsupported model may ignore or speak them.
Does expressive support imply phoneme support?
Does expressive support imply phoneme support?
No. Check each capability independently for the selected TTS model.