Flush syntax
# support
o
I want to check if the LLM is actually generating responses with flush syntax, so I’m trying to extract the raw LLM response. I tested with voice.chunkPlan and voice.chunkPlan.formatPlan.enabled = false, but I didn’t see any tags in the assistant’s output. https://docs.vapi.ai/assistants/voice-formatting-plan#customizing-the-formatting-plan I’ve enabled the required configurations for flush syntax, but the results are inconsistent across calls. https://docs.vapi.ai/assistants/flush-syntax LLM: OpenAI GPT5 Mini Voice: ElevenLabs Has anyone figured out a reliable way to confirm if the LLM is outputting flush tags in its raw response?
c
Hi orthogenius, To get the LLM to use flush syntax, follow these steps: 1. **Flush Configuration**: Make sure to use
<flush />
,
<flush>
, or
</flush>
in the LLM outputs where you want immediate audio feedback. 2. **Voice Configuration**: Check that
voice.chunkPlan
has
"enabled": true
and
"formatPlan": { "enabled": true }
. 3. **Extract Raw LLM Output**: Disable other formatting to see flush tags in the raw output by setting
voice.chunkPlan.formatPlan.enabled = false
. 4. **Troubleshooting**: If flush tags aren't recognized, check for syntax errors or config issues. You can find more details [here](https://docs.vapi.ai/assistants/flush-syntax). Test with different scenarios to see how flush syntax works. If issues continue, review your configurations or simulate responses to pinpoint the problem.
o
Thanks for the reply, Pravin After multiple trials, the LLM did output tags — I verified this by setting voice.chunkPlan.formatPlan.enabled = false. Later, I switched to voice.chunkPlan.enabled = true and formatPlan.enabled = true to see how the flush syntax works. But in the call logs during testing, I noticed "flush": false at the points where I had predefined tags in the system prompt setup.
c
Could you please provide a call id where that occurred?
o
Sure Call IDs where flush configs were enabled but returned "flush": false in call logs: a19d9b74-36a3-466a-b335-a02faa463817 9f9b5691-4415-4ba1-805f-77d54ad7efcd
c
Thank you for the call ids. We will look into this and get back to you
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