What is a speech-to-speech agent?
A standard Bolna agent runs three services in a chain: a transcriber turns caller audio into text, an LLM decides what to say, and a synthesizer turns that back into audio. A speech-to-speech agent replaces all three with one model that takes audio in and produces audio out over a single connection. Because the model never converts speech to text and back, it hears how something was said, not just what was said, and it answers without waiting for three services in sequence.When to choose speech-to-speech
Speech-to-speech suits agents where responsiveness and natural delivery matter more than fine control of each stage. The classic pipeline remains the better fit when you need a specific transcriber for a language or accent, a specific voice from a specific synthesizer, or per-stage control such as keyword boosting.Supported providers
How to configure an agent
A speech-to-speech agent carries ans2s block in tools_config and no llm_agent, transcriber or synthesizer. The pipeline in toolchain is a single s2s stage.
Shared settings
What carries over from a standard agent
Your prompt, welcome message, hangup message,end_call and transfer_call, custom tools with pre-call webhooks, DTMF, ambient noise, recording, transcripts, post-call extraction and billing all behave the same way. Barge-in is handled by the provider rather than by Bolna, and is tuned with the per-provider settings on the pages above.