> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentscope.io/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> For AgentScope Python, use https://docs.agentscope.io/stable/en/index for new projects. For existing projects, check the installed agentscope version and use matching versioned documentation.
> The /latest/ alias points to development documentation. Use it only with the matching development source. Do not mix AgentScope 1.x and 2.x APIs.
> State the AgentScope version when providing installation commands or code examples. ReMe uses its own continuously updated /reme/latest/ documentation.

# Overview

> Talk to an agent by voice, and let it call tools while the conversation runs

<Warning>
  Realtime agents are experimental. The interfaces may change in future releases.
</Warning>

A realtime agent (`RealtimeAgent`) takes speech in and sends speech back: it listens continuously, answers out loud, and calls tools mid-conversation, instead of waiting for a complete text message before replying.

Two implementations exist, differing in how audio reaches the model:

| Implementation             | How it works                                                                                                                       |
| -------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| Speech-to-speech           | Audio flows straight in and out of one end-to-end speech model, which handles recognition, understanding, and synthesis internally |
| Cascaded (ASR + LLM + TTS) | Speech recognition turns the user's voice into text for an `Agent`, and speech synthesis speaks the reply                          |

AgentScope supports the speech-to-speech implementation today; the cascaded one is coming soon. Both share the following capabilities:

| Capability             | Description                                                                                                                                                                   |
| ---------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Turn detection         | Voice activity detection (VAD) decides when the user starts and stops speaking, which marks the turn boundaries. The provider API can do this, or you can plug in a local VAD |
| Barge-in               | The moment the user speaks, the current reply stops, and the context keeps only the part the user actually heard. Your code can interrupt as well                             |
| Tool calling           | Works with `Toolkit` and the permission system, so tools run during the voice conversation                                                                                    |
| Human-in-the-loop      | The agent can ask the user to confirm a tool call without pausing the audio stream                                                                                            |
| Automatic reconnection | After the provider API closes a session, the user's next utterance reconnects it, with the conversation history kept in the agent's state                                     |

Each implementation has its own page:

<CardGroup cols={2}>
  <Card title="Speech-to-Speech" icon="waveform-lines" href="/versions/2.0.8/en/building-blocks/realtime/speech-to-speech" cta="Learn more" arrow>
    Hold a realtime voice conversation through an end-to-end speech model, with barge-in, tool calling, and automatic reconnection.
  </Card>
</CardGroup>