---
url: "https://docs.on-book.app/rehearsal/modes/voice-rehearsal.md"
description: "A full-duplex AI scene partner that reads your cues and listens for your lines."
status: "proposed"
---

# Voice Rehearsal

> **Status: Proposed / pre-launch. On Book Rehearsal docs describe intended behavior and may not match a shipped app yet.**

> **A full-duplex AI scene partner that reads your cues and listens for your lines.**

***

## Overview

Voice Rehearsal lets you run scenes out loud with an AI partner powered by the **Gemini Multimodal Live API**. The AI speaks every character's lines except yours, then listens in real time as you deliver your lines back. It's like having a scene partner available 24/7.

***

## How It Works

1. **Select your scene and character** on the setup screen
2. Tap **Go** to connect to the AI session
3. The AI reads the first cue line aloud
4. **Speak your line** when it's your turn
5. The AI evaluates your delivery, then continues with the next cue
6. Repeat until the scene ends or you stop the session

The conversation is **full-duplex** — you can speak naturally without pressing any buttons. The AI listens continuously and responds in real time.

***

## The On-Book Protocol

The AI follows strict rules to keep the rehearsal authentic:

| Rule | Behavior |
|:---|:---|
| **Never volunteers your lines** | The AI will pause and wait — it won't read your part for you |
| **"Line?" prompt** | If you're stuck, tap the **Line** button or say "line?" and the AI will read only your next line |
| **Stays in character** | The AI performs cue lines with natural pacing, not robotic text-to-speech |
| **Corrects based on strictness** | How strictly the AI corrects you depends on your [strictness level](../guide/strictness.md) |

***

## Strictness in Voice Rehearsal

Your chosen strictness level controls how the AI responds to mistakes:

| Level | Name | Behavior |
|:---|:---|:---|
| 1 | **The Gist** | Very forgiving — paraphrasing is fine; only corrects missed plot points |
| 2 | **Rehearsal** | Standard accuracy — minor word swaps are OK; corrects significant deviations |
| 3 | **Opening Night** | Word-perfect — interrupts on any deviation from the script |

You can change your strictness level in [Settings](../guide/settings.md) or on the rehearsal setup screen.

***

## Session Recap

When you end a session, your performance data is saved:

* **Accuracy percentage** for the session
* **Trouble spots** — lines you struggled with
* **Session history** visible in the [Stats screen](../guide/settings.md#stats)

***

## Tips for Best Results

::: tip Quiet Environment
Background noise can interfere with speech recognition. Rehearse in a quiet space for the most accurate experience.
:::

::: tip Use Headphones
Headphones prevent the AI's audio output from being picked up by your microphone, which improves recognition accuracy.
:::

::: tip Mic Positioning
Keep your device within arm's reach with the microphone unobstructed. Avoid covering the mic with your hand or placing the device face-down.
:::

***

## Access Requirements

Voice Rehearsal is proposed behavior. Access tiers, billing, and production-member entitlements are not public commitments yet. If you are testing Rehearsal, use the access instructions provided by the owner/operator.

***

## Troubleshooting

| Problem | Solution |
|:---|:---|
| AI doesn't hear me | Check [microphone permissions](../reference/troubleshooting.md#microphone-permissions) in your device settings |
| Audio is choppy or delayed | Ensure a stable internet connection — Voice Rehearsal requires real-time streaming |
| AI reads my lines instead of waiting | Make sure you've selected the correct character on the setup screen |
| Session won't start | Check your access status in [Settings](../guide/settings.md) |

For more help, see the full [Troubleshooting](../reference/troubleshooting.md) guide.

***

## Related Guides

* [Italian Run (Speed Drill)](./italian-run.md)
* [Flashcard Mode](./flashcard.md)
* [Strictness Levels](../guide/strictness.md)
* [Scene & Character Selection](../guide/scene-selection.md)

***

*Last updated: February 19, 2026*