pptx-to-md

Extract PPTX to per-slide markdown

This skill turns a .pptx file into one markdown file per slide, preserving layout context and image meaning. It does not paraphrase the text or describe images out of context. The output is suitable as input to a content uplift pass, a markdown-to-HTML build, or any other downstream transform.

When to use

The deck mixes text with embedded screenshots, diagrams, charts, or code samples in a layout that matters (columns, side-by-side panels, callouts). Plain text extraction would lose either the layout or the meaning of the images.

IMPORTANT: If the deck is: a PDF, text-only or if it has no images that are meaningful to the content, uvx 'markitdown[all]' <path-to-file> -o output.md is faster and usually sufficient without going through this skill's more complex pipeline as described below. You can try this and ask the user to review the output letting them know that if it's not sufficient you will continue with the more complex slide extraction pipeline.

Pipeline

PPTX -> prepare.py -> manifests + rendered JPGs + embedded PNGs
     -> dispatch one sub-agent per slide
     -> per-slide markdown files
     -> concatenate.py -> deck.md

The orchestrator (you, in the calling session) does two things: run the prepare and concatenate scripts, and dispatch one sub-agent per visible slide. Each sub-agent does the actual vision-and-text composition for one slide and writes one markdown file. Sub-agents are independent so they parallelise cleanly.

Step 1 - prepare the workspace

python <skill>/scripts/prepare.py <pptx-path> <workspace-dir>

This unzips the PPTX, renders every visible slide to a JPG via LibreOffice and pdftoppm, then writes one manifest JSON per visible slide. After rendering, the script checks the JPG count matches the slide count and warns to stderr if they diverge - LibreOffice has been known to silently drop slides, so always read that warning before dispatching sub-agents.

Run this step OUTSIDE any command sandbox. LibreOffice headless needs to write its per-user profile and set OS/task policies that a sandbox blocks, so under sandboxing soffice fails silently: no PDF, empty output, and no deck_index.json. Under Claude Code specifically, run prepare.py with the Bash tool's dangerouslyDisableSandbox: true. Symptom to recognise: rendered/ stays empty and no deck_index.json is written while the soffice process sits at near-zero CPU.