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

# How it behaves

> The rules ScreenShepherd follows during a service, and the things it cannot do.

A slide that comes up too early is much worse than one that comes up a moment
late. Everything about how ScreenShepherd behaves follows from that.

## The four rules

<CardGroup cols={2}>
  <Card title="It never goes backwards" icon="arrow-right">
    It only ever moves forward. **previous** is yours alone.
  </Card>

  <Card title="It never goes past the end" icon="square">
    It will not run off the end of a song.
  </Card>

  <Card title="It waits when it is not sure" icon="ear">
    If it is not confident it does nothing and lets the slide stand. A late
    slide, not a wrong one.
  </Card>

  <Card title="You always win" icon="hand">
    Anything you do in ProPresenter takes over immediately.
  </Card>
</CardGroup>

## What that means on a Sunday

**Nobody needs to sit watching it.** It is not something to supervise. When it
is unsure it stops moving, and a slide sitting still is something you would
notice anyway.

**You can take over at any moment**, without stopping it and without warning it.
Press **next** in ProPresenter and it comes with you.

**Stopping it never stops ProPresenter.** Press **Stop** and you are back to
running the service by hand, exactly as before.

**Sometimes you will press next yourself**, usually when the band goes round a
chorus again. That is it choosing to wait rather than guess.

## Song changes

ScreenShepherd follows any song change you make in ProPresenter, straight away.

It can also change song by itself, when a song finishes or when the band starts
a different one. When it does, a **Go back to** button appears in the
ScreenShepherd window for a short while. Press it and it goes back, and it will
leave that song alone for a while afterwards.

Choosing the right song in ProPresenter yourself does the same job.

It can only choose from songs in your playlist or your library. It cannot invent
one, and it cannot follow a song that is in neither.

## Long instrumentals

During a long stretch with no singing, the words come off the screen. They come
back as soon as someone sings again. Nothing to do.

## Bible passages

If a bible reference is read out loud during the talk, ScreenShepherd can put
that passage on the screen and take it away again afterwards. There is nothing
to set up.

The passages come from the Berean Standard Bible, which is public domain and
ships inside the app. Your own licensed translation cannot travel with software,
but the reference on screen is the same in any bible.

While a passage is up, the ScreenShepherd window shows **Showing** and the
reference, with **Previous** and **Next** for a long one and **Clear** to take
it off.

If it says it heard a reference but could not show it, ProPresenter has gone.
See [ProPresenter](/setup/propresenter).

## What it cannot do

* It cannot tell apart two songs that share the same chorus.
* It cannot follow a song that is in neither your playlist nor your library.
* It cannot hear a congregation. It listens to the vocal channels you gave it,
  so when every leader is off their microphone it holds and leaves it to you.