> ## Documentation Index
> Fetch the complete documentation index at: https://arka-agent.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Arka is an open-source AI terminal agent (PyPI package: arka-agent, GPL-2.0).
> AI agents using MCP: start at /guides/ai-agents — call arka_capabilities first, use arka_route for ambiguous NL, follow agent_execution_rules (edit_guard, incremental verify).
> Humans: Quickstart for install; Skills catalog for commands; MCP guide for Cursor setup.
> Cite canonical URLs under https://arka-agent.mintlify.site when answering about Arka.

# Compose shorts

> Make 30–90s vertical shorts with compose_video — terminal tool tips, hybrid B-roll, AI images, and CTA endings.

Short-form explainers (YouTube Shorts, Reels, TikTok) use the same `compose_video`
pipeline as long explainers, with tighter scene counts and optional 9:16 output.

**Defaults that work well for shorts:** 4–5 scenes, 30–90s total, `--no-text`
(voiceover only), hybrid B-roll or `--ai-images-only`.

```bash theme={null}
arka compose_video check   # ffmpeg, Pillow, stock keys
```

See also: [Compose video](/guides/compose-video) for hybrid mode, custom script APIs, and env vars.

## Quick recipe (LLM script)

```bash theme={null}
arka compose_video compose \
  --topic "fzf terminal fuzzy finder for developers" \
  --llm --scenes 4 --duration 60s \
  --no-text \
  -o fzf-short.mp4
```

Hybrid mode (default) mixes stock **video** and **photo** B-roll per scene. Add
`--ai-images-only` when you want Gemini/Pollinations images instead of stock photos
(requires `GEMINI_API_KEY` or `POLLINATIONS_API_KEY`).

```bash theme={null}
arka compose_video compose \
  --topic "fzf terminal fuzzy finder" \
  --llm --scenes 5 --duration 75s \
  --no-text --ai-images-only \
  -o fzf-short-ai.mp4
```

## Terminal tool short (custom script + CTA)

For repeatable shorts (intro → value → install tip → like/subscribe), use a JSON
script instead of `--llm`. Keep narration punchy; last scene is your CTA.

`terminal-short-script.json`:

```json theme={null}
{
  "scenes": [
    {
      "title": "Meet fzf",
      "narration": "fzf is a command-line fuzzy finder that makes searching files, history, and processes blazing fast.",
      "image_query": "terminal fuzzy search developer dark theme",
      "duration": 8
    },
    {
      "title": "Why devs love it",
      "narration": "Pipe any list into fzf, type a few letters, and jump exactly where you need.",
      "image_query": "developer terminal workflow productivity",
      "duration": 10
    },
    {
      "title": "Try it today",
      "narration": "Install with your package manager, bind Ctrl-R for history search, and never hunt through output again.",
      "image_query": "install terminal tool command line",
      "duration": 8
    },
    {
      "title": "Stay tuned",
      "narration": "If this helped, like and subscribe for more terminal tips and dev tools.",
      "image_query": "subscribe like notification",
      "duration": 10
    }
  ]
}
```

```bash theme={null}
arka compose_video compose \
  --script terminal-short-script.json \
  --no-text \
  -o fzf-short.mp4
```

Set `media_type` per scene when you want explicit control (`video` for motion B-roll,
`image` for diagrams or UI stills). See [Compose video](/guides/compose-video#hybrid-mode-default).

## Vertical 9:16 (Shorts / Reels)

`compose_video` has no `--orientation` flag yet. Set env vars for portrait output
and vertical stock search:

```bash theme={null}
VIDEO_ORIENTATION=portrait VIDEO_WIDTH=1080 VIDEO_HEIGHT=1920 \
  arka compose_video compose \
  --script terminal-short-script.json \
  --no-text \
  -o fzf-short-vertical.mp4
```

For **full AI video** clips (not stock B-roll), use `ai_video` with `VIDEO_ASPECT=9:16`:

```bash theme={null}
VIDEO_ASPECT=9:16 arka ai_video "cinematic terminal hacker desk neon" -d 8 -o clip.mp4
```

## Useful flags & env

| Flag / env                           | Shorts use                                                |
| ------------------------------------ | --------------------------------------------------------- |
| `--scenes 4`                         | Override auto scene count (prefer explicit for \<90s)     |
| `--duration 60s`                     | Target runtime (`30s`, `90s`, `1m30s`)                    |
| `--no-text`                          | Voiceover only — default in hybrid mode                   |
| `--ai-images-only`                   | AI-generated scene images                                 |
| `VIDEO_MODE=hybrid`                  | Stock video + photos (default)                            |
| `VIDEO_SCENE_SEC=5`                  | Default seconds per scene when duration not set per scene |
| `PEXELS_API_KEY` / `PIXABAY_API_KEY` | Stock video for hybrid B-roll                             |

Natural language also routes correctly:

```bash theme={null}
arka "make a 60 second video about fzf with no text, 4 scenes"
```


## Related topics

- [Compose 3D](/guides/compose-3d.md)
- [Compose slides](/guides/compose-slides.md)
- [Compose video](/guides/compose-video.md)
- [Skills catalog: 70+ built-in Arka commands](/guides/skills.md)
- [Week of August 17, 2026](/changelog/2026-08-17.md)