pre — slide + audio container CLI

pre is a small CLI that does exactly two things:

1. pre package — bundle a slides/ directory (one HTML file per page) and an audio/ directory (one audio file per page, matching basename) into a single .pre file. A browser player is embedded automatically.
2. pre play — extract a .pre, serve it on a local 127.0.0.1 port, and open the browser player. The server shuts itself down when the browser goes away.

It never generates content, runs TTS, calls an LLM, or converts PDF/PPTX. Produce the slides/ and audio/ inputs yourself (write HTML, export from tools, or use other skills/agents), THEN call pre package.

Install

Recommended: grab a prebuilt binary from Releases, or use Homebrew:

brew install --cask Z-Mackintosh/tap/pre   # macOS

Build from source instead (requires Go 1.23+):

go install github.com/Z-Mackintosh/pre@latest
# or: git clone https://github.com/Z-Mackintosh/pre.git && cd pre && go build -o pre .

The binary lands in $(go env GOPATH)/bin (%USERPROFILE%\go\bin on Windows) — make sure it is on PATH.

Verify:

pre -h
# pre — slide + audio container
#   pre package --slides <dir> --audio <dir> -o <file.pre> [--title T] [--author A] [--notes notes.md]
#   pre play <file.pre>

If pre is not found, ensure $(go env GOPATH)/bin is on PATH:

case ":$PATH:" in *":$(go env GOPATH)/bin:"*) ;; *) export PATH="$(go env GOPATH)/bin:$PATH";; esac

Installing this skill into an agent

This skill is just this SKILL.md file — the repo is the pre CLI project, not a skill repo. Do not clone the whole repo into your skills directory (that pulls in main.go, internal/, samples/, etc.). Place skill/SKILL.md into your agent's skills directory as pre/SKILL.md.

Common skills directories: Claude Code ~/.claude/skills/, Codex ~/.codex/skills/, Cursor .cursor/skills/ (project-level). See your agent's docs for others.

A. download the single file (recommended)

mkdir -p ~/.<agent>/skills/pre
curl -fsSL https://raw.githubusercontent.com/Z-Mackintosh/pre/main/skill/SKILL.md \
  -o ~/.<agent>/skills/pre/SKILL.md

B. copy from a local clone (if you cloned the repo to build the CLI)

mkdir -p ~/.<agent>/skills/pre
cp /path/to/pre/skill/SKILL.md ~/.<agent>/skills/pre/SKILL.md

C. ask the agent to install it

Install the pre skill. The repo is a CLI project, not a skill repo — only skill/SKILL.md is the skill. Do NOT clone the whole repo. Download https://raw.githubusercontent.com/Z-Mackintosh/pre/main/skill/SKILL.md to ~/.<agent>/skills/pre/SKILL.md, verify it, then confirm.

To update later, re-run the download command.

This skill assumes the pre CLI is already installed and on PATH.

Input conventions (critical)

pre package takes two directories. Files are paired by basename:

slides/            audio/
  01.html   <-->     01.mp3
  02.html   <-->     02.m4a
  intro.html <-->   intro.wav

• slides/: one .html file per page. Order is by filename sort. Each HTML is a complete standalone page (it will be loaded in an <iframe>).
• audio/: one audio file per slide, basename must match the HTML exactly. Supported formats: wav, mp3, m4a, ogg. Formats can be mixed across slides. Audio duration is probed to build the timeline — there is no trimming, splitting, or transcoding.
• A slide with no matching audio (or vice versa) is an error. Use the same basename for every pair (e.g. 03.html + 03.ogg, NOT 03.html + slide3.ogg).

The CLI copies inputs verbatim into the container. It never modifies them.

Commands

pre package

pre package --slides <slides-dir> --audio <audio-dir> -o <out.pre> \
  [--title "Talk title"] [--author "Name"] [--notes notes.md]

Produces <out.pre> (a ZIP) containing manifest.json, slides/, audio/, the embedded player/, and optional notes.md.

Example:

pre package --slides ./slides --audio ./audio -o talk.pre \
  --title "Q3 roadmap" --author "me" --notes script.md

pre play

pre play <file.pre>

Extracts to a temp dir, serves on http://127.0.0.1:<random-port>/, opens the browser at the player. The local server auto-shuts-down once the browser stops sending heartbeats (~5s of inactivity), and cleans up temp files. Listens only on 127.0.0.1 (never exposed to the LAN).

Player controls (no visible UI — keyboard only)

Typical agent workflow

1. Generate slides/01.html, 02.html, … (write HTML yourself, export from a tool, or use another skill). Each file is a full standalone HTML page.
2. Generate audio/01.<fmt>, 02.<fmt>, … with matching basenames (record, TTS, etc.). Any of wav/mp3/m4a/ogg, mixable.
3. pre package --slides slides --audio audio -o out.pre --title "...".
4. To verify: pre play out.pre (opens a browser; close the tab to stop).

Do NOT ask pre to write copy, synthesize speech, or convert PDF/PPTX. Do those upstream and hand the resulting files to pre package.

Container layout (for reference)

out.pre  (ZIP)
├── manifest.json     # version, title, author, timeline (start/end per slide)
├── slides/NN.html
├── audio/NN.<fmt>
├── player/           # player.html, app.js, style.css (embedded by CLI)
└── notes.md          # optional, only if --notes given

manifest.json example:

{
  "version": "1.0.0",
  "title": "...",
  "author": "...",
  "slides": [
    { "id": "01", "file": "slides/01.html", "audio": "audio/01.mp3",
      "start": 0.0, "end": 12.5 }
  ]
}

Troubleshooting

• pre: command not found → $(go env GOPATH)/bin not on PATH (see Install).
• package: no audio matching slide "01" → basename mismatch; the audio file for 01.html must be named 01.* (same basename, any supported ext).
• play: container has no player/player.html → the file is not a .pre produced by pre package.

License

MIT. Source: https://github.com/Z-Mackintosh/pre