pptx-custom

name: pptx-custom description: "Use this skill any time a .pptx file is involved in any way — as input, output, or both. This includes: creating slide decks, pitch decks, or presentations; reading, parsing, or extracting text from any .pptx file (even if the extracted content will be used elsewhere, like in an email or summary); editing, modifying, or updating existing presentations; combining or splitting slide files; working with templates, layouts, speaker notes, or comments; recovering decks that refuse to open in PowerPoint Online or that PowerPoint Desktop opens with a silent "Repaired" companion (Walnut Exporter, Aspose, Syncfusion, Spire, GemBox, OpenXML-SDK pipelines, or any non-Office producer). Trigger whenever the user mentions "deck," "slides," "presentation," or references a .pptx filename, regardless of what they plan to do with the content afterward. If a .pptx file needs to be opened, created, or touched, use this skill."

PPTX Skill

Intent Router

Load sections based on the task:

• Edit existing presentation → ALWAYS run scripts/check_fragility.py first, then read editing.md for the standard unpack/edit/pack workflow. If the fragility check reports any finding, switch to recovering-fragile-decks.md.
• Fragile / foreign-exporter deck → Read recovering-fragile-decks.md for canonicalization and byte-level surgical-patch workflows. Required whenever the file was produced by Walnut Exporter, Aspose, Syncfusion, Spire, GemBox, OpenXML SDK pipelines, or any non-Office producer.
• Create from scratch → Read pptxgenjs.md for generation mechanics and effective-maintainable-decks.md for editable, reusable, Office-compatible deck guidance; use the PptxGenJS library. If the request includes brand or theme inputs, use PptxGenJS theme fonts plus defineSlideMaster(...) / addSlide({ masterName: "..." }), then verify the generated OOXML theme and layout parts.
• Extract/analyze content → Use markitdown or thumbnail.py from "Reading Content"
• Design guidance → "Design Ideas" section for color palettes, typography, spacing, and anti-patterns; use effective-maintainable-decks.md when maintainability, reuse, or MS Office compatibility matters
• Visual QA → "QA (Required)" section for converting to images and inspection workflow
• Converting to images → "Converting to Images" section for pdftoppm workflow

Quick Start

For any .pptx request, first identify whether the file is being read, edited, created, or visually checked.

Quote file paths in shell commands when they contain spaces; the examples below use short placeholder filenames for readability.

# Read slide text and speaker-note content
python -m markitdown presentation.pptx

# Render a contact sheet for fast visual review
python pptx-custom/scripts/thumbnail.py presentation.pptx presentation-contact-sheet.jpg --cols 4 --dpi 120

# Check provenance before editing any existing deck
python pptx-custom/scripts/check_fragility.py presentation.pptx

• For editing, stop after check_fragility.py if it reports findings and follow recovering-fragile-decks.md; otherwise follow editing.md.
• For new decks, follow pptxgenjs.md, then apply effective-maintainable-decks.md before QA. When brand or theme inputs are supplied, confirm the result uses theme fonts and master-backed slide layouts instead of per-slide manual styling.
• For delivery review, run content extraction plus thumbnail/contact-sheet rendering, then complete the QA loop before declaring the deck finished.

Quick Reference

Reading Content

# Text extraction
python -m markitdown presentation.pptx

# Visual overview
python pptx-custom/scripts/thumbnail.py presentation.pptx

# Raw XML
python office-custom/scripts/unpack.py presentation.pptx unpacked/

Editing Workflow

Read editing.md for full details.

1. Provenance check — python pptx-custom/scripts/check_fragility.py file.pptx. Any finding means switch to recovering-fragile-decks.md; a normalizing re-save (python-pptx, ElementTree round-trip in pack.py) on a Walnut-style deck can break the file in both PowerPoint Online and PowerPoint Desktop, even when LibreOffice still opens it.
2. Analyze template with thumbnail.py
3. Unpack → manipulate slides → edit content → clean → pack

Creating from Scratch

Read pptxgenjs.md for full details. For client-facing, collaborative, or reusable decks, also read effective-maintainable-decks.md.

Use when no template or reference presentation is available.

Design Ideas

Don't create boring slides. Plain bullets on a white background won't impress anyone. Consider ideas from this list for each slide.

Before Starting

• Pick a bold, content-informed color palette: The palette should feel designed for THIS topic. If swapping your colors into a completely different presentation would still "work," you haven't made specific enough choices.
• Dominance over equality: One color should dominate (60-70% visual weight), with 1-2 supporting tones and one sharp accent. Never give all colors equal weight.
• Dark/light contrast: Dark backgrounds for title + conclusion slides, light for content ("sandwich" structure). Or commit to dark throughout for a premium feel.
• Commit to a visual motif: Pick ONE distinctive element and repeat it — rounded image frames, icons in colored circles, thick single-side borders. Carry it across every slide.

Color Palettes

Choose colors that match your topic — don't default to generic blue. Use these palettes as inspiration:

For Each Slide

Every slide needs a visual element — image, chart, icon, or shape. Text-only slides are forgettable.

Layout options:

• Two-column (text left, illustration on right)
• Icon + text rows (icon in colored circle, bold header, description below)
• 2x2 or 2x3 grid (image on one side, grid of content blocks on other)
• Half-bleed image (full left or right side) with content overlay

Data display:

• Large stat callouts (big numbers 60-72pt with small labels below)
• Comparison columns (before/after, pros/cons, side-by-side options)
• Timeline or process flow (numbered steps, arrows)

Visual polish:

• Icons in small colored circles next to section headers
• Italic accent text for key stats or taglines

Typography

Choose an interesting font pairing — don't default to Arial. Pick a header font with personality and pair it with a clean body font.

Spacing

• 0.5" minimum margins
• 0.3-0.5" between content blocks
• Leave breathing room—don't fill every inch

Avoid (Common Mistakes)

• Don't repeat the same layout — vary columns, cards, and callouts across slides
• Don't center body text — left-align paragraphs and lists; center only titles
• Don't skimp on size contrast — titles need 36pt+ to stand out from 14-16pt body
• Don't default to blue — pick colors that reflect the specific topic
• Don't mix spacing randomly — choose 0.3" or 0.5" gaps and use consistently
• Don't style one slide and leave the rest plain — commit fully or keep it simple throughout
• Don't create text-only slides — add images, icons, charts, or visual elements; avoid plain title + bullets
• Don't forget text box padding — when aligning lines or shapes with text edges, set margin: 0 on the text box or offset the shape to account for padding
• Don't use low-contrast elements — icons AND text need strong contrast against the background; avoid light text on light backgrounds or dark text on dark backgrounds
• NEVER use accent lines under titles — these are a hallmark of AI-generated slides; use whitespace or background color instead

QA (Required)

Assume there are problems. Your job is to find them.

Your first render is almost never correct. Approach QA as a bug hunt, not a confirmation step. If you found zero issues on first inspection, you weren't looking hard enough.

Content QA

python -m markitdown output.pptx

Check for missing content, typos, wrong order.

When using templates, check for leftover placeholder text:

python -m markitdown output.pptx | grep -iE "\bx{3,}\b|lorem|ipsum|\bTODO|\[insert|this.*(page|slide).*layout"

If grep returns results, fix them before declaring success.

Visual QA

⚠️ USE SUBAGENTS — even for 2-3 slides. You've been staring at the code and will see what you expect, not what's there. Subagents have fresh eyes.

Convert slides to images (see Converting to Images), then use this prompt:

Visually inspect these slides. Assume there are issues — find them.

Look for:
- Overlapping elements (text through shapes, lines through words, stacked elements)
- Text overflow or cut off at edges/box boundaries
- Decorative lines positioned for single-line text but title wrapped to two lines
- Source citations or footers colliding with content above
- Elements too close (< 0.3" gaps) or cards/sections nearly touching
- Uneven gaps (large empty area in one place, cramped in another)
- Insufficient margin from slide edges (< 0.5")
- Columns or similar elements not aligned consistently
- Low-contrast text (e.g., light gray text on cream-colored background)
- Low-contrast icons (e.g., dark icons on dark backgrounds without a contrasting circle)
- Text boxes too narrow causing excessive wrapping
- Leftover placeholder content
- Flattened screenshots where editable text, charts, tables, or native diagrams
  are expected
- Missing unique slide titles, inaccessible reading order, or missing alt text on
  meaningful visuals
- Template drift: recurring content rebuilt as local formatting instead of using
  masters, layouts, placeholders, theme colors, and native PowerPoint objects
- Office compatibility risks such as unsupported fonts, unmanaged linked media,
  complex SmartArt, macros, OLE/ActiveX objects, or brittle animation trees

For each slide, list issues or areas of concern, even if minor.

Read and analyze these images — run `ls -1 "$PWD"/slide-*.jpg` and use the exact absolute paths it prints:
1. <absolute-path>/slide-N.jpg — (Expected: [brief description])
2. <absolute-path>/slide-N.jpg — (Expected: [brief description])
...

Report ALL issues found, including minor ones.

Verification Loop

1. Generate slides → Convert to images → Inspect
2. List issues found (if none found, look again more critically)
3. Fix issues
4. Re-verify affected slides — one fix often creates another problem
5. Repeat until a full pass reveals no new issues

Do not declare success until you've completed at least one fix-and-verify cycle.

Converting to Images

Convert presentations to individual slide images for visual inspection:

python office-custom/scripts/soffice.py --headless --convert-to pdf output.pptx
rm -f slide-*.jpg
pdftoppm -jpeg -r 150 output.pdf slide
ls -1 "$PWD"/slide-*.jpg

Pass the absolute paths printed above directly to the view tool. The rm clears stale images from prior runs. pdftoppm zero-pads based on page count: slide-1.jpg for decks under 10 pages, slide-01.jpg for 10-99, slide-001.jpg for 100+.

After fixes, rerun all four commands above — the PDF must be regenerated from the edited .pptx before pdftoppm can reflect your changes.

Dependencies

• pip install "markitdown[pptx]" - text extraction
• pip install Pillow - thumbnail grids
• npm install pptxgenjs - creating from scratch with project-local Node scripts. If installed globally, set NODE_PATH to npm root -g before running scripts that call require("pptxgenjs").
• LibreOffice (soffice) - PDF conversion (auto-configured for sandboxed environments via office-custom/scripts/soffice.py). On Windows: winget install --id TheDocumentFoundation.LibreOffice --source winget
• Poppler (pdftoppm) - PDF to images

API Reference

The PptxGenJS and python-pptx API quick lookups have moved to api-reference.md to keep this file scannable. Load that file for property tables, option blocks, and constructor signatures.

See Also

• editing.md — unpack/edit/repack workflow for healthy decks.
• recovering-fragile-decks.md — fragility detection, canonicalization, and byte-level surgical patching for decks produced by Walnut Exporter and other non-Office tools.
• pptxgenjs.md — creating new decks from scratch.
• effective-maintainable-decks.md — effective, editable, reusable, and Office-compatible deck construction.
• api-reference.md — PptxGenJS and python-pptx API quick reference.
• $raw-document — specification-level reference (OOXML/ODF schemas, namespace tables, package structure deep-dives, cross-format mapping). Use when this skill's content is insufficient or when schema validation, format recovery, or deep PresentationML element research is required.