Deck AI

deck-ai

Turn plain markdown into a themed, image-rich slide deck exported as PDF. Closest open-source equivalent to Gamma. Runs locally. No subscription.

What this skill does

1. Reads source markdown (slides separated by ---).
2. Picks a layout + image keyword per slide. Two modes:
   • LLM mode (preferred): Claude writes decisions.json directly using the Write tool. No extra API call.
   • Rules mode (fallback): deterministic regex picks. Used when the skill is invoked from a non-LLM harness.
3. Fetches images from Unsplash by keyword.
4. Renders the whole thing to PDF via Slidev.

When to invoke

Triggers: "make a deck", "turn this into slides", "slide version of X", "build a presentation from this", "gamma-style deck".

Do NOT invoke for plain editing / rewriting of existing slide content. Do NOT invoke if the user wants a PPTX specifically (use python-pptx instead).

Required setup (first run)

Prerequisites

• Node 18+ and pnpm on the user's machine. If missing:

  brew install node
  npm install -g pnpm
  

API key

• Unsplash (required): https://unsplash.com/oauth/applications — only the Access Key.
• Key lives in .env at the calling instance root:

  echo 'UNSPLASH_ACCESS_KEY=<your-key>' >> ./.env
  

• Never commit .env. Never paste the key into any file in this skill.
• No separate Anthropic key needed — when this skill runs inside Claude Code, Claude itself writes decisions.json.

Install workspace (one-time per instance)

bash <skill>/scripts/setup.sh ./deck-workspace

This creates a local Slidev workspace with themes installed. Takes ~1-2 minutes first run. Subsequent runs reuse it.

Workflow (per deck)

# 1. Preflight: key + deps must be present
bash <skill>/scripts/check_env.sh ./deck-workspace

# 2. (LLM mode) Claude reads <input.md>, decides layout + image keyword
#    per slide, and WRITES ./deck-workspace/decisions.json with the Write
#    tool (schema below). Skip this step when running outside Claude.

# 3. Generate Slidev markdown from source
#    LLM mode:
python3 <skill>/scripts/generate.py <input.md> ./deck-workspace/slides.raw.md \
    --theme seriph --decisions ./deck-workspace/decisions.json
#    Rules mode (no decisions file):
python3 <skill>/scripts/generate.py <input.md> ./deck-workspace/slides.raw.md --theme seriph

# 4. Fill image placeholders from Unsplash
python3 <skill>/scripts/fetch_images.py ./deck-workspace/slides.raw.md

# 5. Export PDF
bash <skill>/scripts/render.sh ./deck-workspace ./deck-workspace/slides.raw.md ./deck.pdf

decisions.json schema (step 2)

One object per slide, in source order. generate.py validates this file and exits non-zero on any violation.

[
  {"layout": "cover",       "image_keyword": "sunrise mountains"},
  {"layout": "image-right", "image_keyword": "student classroom"},
  {"layout": "center",      "image_keyword": null},
  {"layout": "end",         "image_keyword": null}
]

Rules Claude must follow when writing decisions.json:

• layout is one of: cover, center, statement, two-cols, image-right, image-left, quote, end, default.
• Slide 1 must be cover.
• If a slide has <!-- layout: X --> in the source, use that layout.
• image_keyword is 1-3 concrete nouns suitable for stock photo search. Required for cover, image-right, image-left. null for every other layout.
• No brand names, no anime character names, no abstract concepts. Use the underlying physical scene instead.

Good keywords: library books, koi fish, child drawing, mountain sunrise. Bad keywords: Naruto, loneliness, theme of courage, The Ordinary World.

Source markdown format

Slides separated by a line containing only ---. First slide is the cover.

Example:

# Deck Title

Subtitle line.

---

# Second slide

Body content here.

<!-- layout: image-right -->

Anime anchor: Naruto.

---

# Homework

Optional closing text.

Layouts

See references/layout-catalog.md for the full enum and pick rules. Force a layout by adding <!-- layout: <name> --> in a slide body.

Image keywords

Use concrete nouns in {{IMG:keyword}} placeholders. 1-3 words. Good: mountain sunrise, library books, child drawing. Bad: feeling of wonder, theme of courage (abstract concepts return weak results).

Themes

Default: @slidev/theme-seriph (clean serif, modern). Fallback: @slidev/theme-default (sans-serif, minimal).

Install more themes in the workspace:

cd ./deck-workspace && pnpm add @slidev/theme-<name>

Browse: https://sli.dev/resources/theme-gallery

Limitations

• Slidev renders via Playwright Chromium on first export (adds ~30s).
• Unsplash free tier: 50 requests/hour. Reuse keywords if hitting the limit.
• PDF export does not preserve interactive elements (embeds, live code).
• Slide source must be standard markdown. HTML-heavy content may break layout.

Troubleshooting

What this skill does NOT do (v2)

• AI-generated images (Unsplash stock only; could add Flux/Ideogram later)
• Brand theme editor (use provided themes or install more via pnpm)
• Per-slide image retries (one Unsplash result per keyword; no ranking)