Explainroo

---
name: explainroo
description: Make an explainer video (MP4) with a voice-over using explainroo. The voice is made on this computer and no API key is needed. Use when the user asks for an explainer, how-to, walkthrough, launch or tutorial video, an animated diagram with a voice-over, or a short for YouTube, Reels or TikTok.
---

# Make an explainer video with explainroo

explainroo makes an MP4 video from two files: a script with the words the
voice says, and a small JavaScript file that draws the pictures. A voice
model on this computer reads the script. explainroo writes down when each
word is spoken, Chrome draws the frames, and explainroo adds music and sound
effects.

## Find or install explainroo

Try these first:

```bash
command -v explainroo
ls "${EXPLAINROO_HOME:-$HOME/.explainroo}/bin/explainroo.js"
```

If neither exists, install it. It needs Node.js 20.11 or newer, ffmpeg, and
Chrome or Chromium.

```bash
git clone https://github.com/vincentsch/explainroo.git "$HOME/.explainroo"
cd "$HOME/.explainroo" && npm install
node bin/explainroo.js doctor --fetch
```

In the rest of this file, `explainroo` means whichever one you found: the
`explainroo` command, or `node "$HOME/.explainroo/bin/explainroo.js"`.

## Read AGENTS.md

`AGENTS.md` in the explainroo folder has the steps, the writing rules, the
settings and the Scene API, which is the list of everything `scenes.js` can
draw. Read it before you start.

## Make the video

Create the project where the user wants it, for example `./video`:

```bash
explainroo init video --theme paper --title "..."
```

Then follow the steps in AGENTS.md. When the video is done, tell the user
where `video/out/video.mp4` is, how long it is, and what
`explainroo verify video` said.