Anthropic skill
pptx
Use this skill any time a .pptx or .potx 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 or .potx 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 (.potx), layouts, speaker notes, or comments. Trigger whenever the user mentions \"deck,\" \"slides,\" \"presentation,\" or references a .pptx or .potx filename, regardless of what they plan to do with the content afterward. If a .pptx or .potx file needs to be opened, created, or touched, use this skill.
A `.pptx` is a ZIP archive of XML files. Choose your approach by task:
#pdf
#documents
#presentations
#slides
#design
Last updated
16 days ago
Repository path
skills/pptx
Source files
3
Use cases
A `.pptx` is a ZIP archive of XML files. Choose your approach by task:
| Task | Approach |
|---|---|
| **Create** a new deck | Write a `pptxgenjs` script — see gotchas below |
| **Edit** an existing deck, or build from a template | unzip → edit `ppt/slides/slideN.xml` → zip |
| **Read** content | `markitdown deck.pptx` (one block per slide under `<!-- Slide number: N -->` markers); visual grid: `python scripts/thumbnail.py deck.pptx` |
- **Set `pres.layout` before adding slides.** The default canvas is `LAYOUT_16x9` = **10" × 5.625"**, not 13.3" wide. Coordinates past the edge are written, not clamped — the shape just isn't on the slide. (`LAYOUT_WIDE` is 13.3" × 7.5".)
- **Hex colors: never `#`, never 8 digits.** `color: "FF0000"`. Both `"#FF0000"` and alpha baked into the hex (`"00000020"`) **corrupt the file**. For translucency: `transparency: 0-100` on fills and images, `opacity: 0.0-1.0` on shadows — each is silently ignored on the other.
- **pptxgenjs mutates option objects in place** (converts values to EMU on first use). Never share one `shadow`/options object across two `add*` calls — build a fresh object each time.
- **Shadow `offset` must be ≥ 0** — a negative offset corrupts the file. To cast a shadow upward, use `angle: 270` with a positive offset.
- **`letterSpacing` is silently ignored** — the real option is `charSpacing`.
- **Lists:** `bullet: true` on each item, never a literal `•` (renders double bullets). Set `breakLine: true` on every array item except the last. Space bulleted paragraphs with `paraSpaceAfter`, not `lineSpacing` (huge gaps).
- **One `new pptxgen()` per output file** — never reuse an instance.
- **`rectRadius` only works on `ROUNDED_RECTANGLE`**, not `RECTANGLE`.
- **Gradient fills aren't supported** — use a gradient image as the background instead.
- **Text boxes have built-in internal padding** — set `margin: 0` whenever text must align with a shape, line, or icon at the same x.
- **Speaker notes go in `slide.addNotes("...")`** (plain text, once per slide), never in a text box on the slide.
- **Keep charts native.** Use `addChart()` for everything PowerPoint can chart (pass an array of `{type, data, options}` for combos). For PowerPoint-native features the library doesn't expose (trendlines, error bars), compute the extra series yourself or post-process the generated OOXML — do not fall back to a rendered image. Only chart types PowerPoint has no native form for (Sankey, network, chord) go in as images.
- **Default charts render bare** — no title, no data labels, dated palette. Set `showTitle` + `title`, `showValue: true` + `dataLabelPosition`, `chartColors: [...]` from your palette, and quiet the frame (`catAxisLabelColor`/`valAxisLabelColor`, `valGridLine: { color, size }`, `catGridLine: { style: "none" }`, `showLegend: false` for a single series).
- **On a stacked bar or column chart, `dataLabelPosition` must be `ctr`, `inEnd`, or `inBase`.** `outEnd` **corrupts the file**.
- **A combo series using `secondaryValAxis`/`secondaryCatAxis` needs both `valAxes` and `catAxes` on the chart options, two entries each.** Without them pptxgenjs writes axis *ids* it never declares, and PowerPoint **discards that chart** and reports the file as corrupt. Supplying only `valAxes` is not enough.
- **After `writeFile()`, run `python scripts/office/validate.py deck.pptx`.** It reports the two chart faults above and the slide-XML defects PowerPoint refuses, and names the fix for each. Fix them in your generator, not by hand-editing the packed XML.
- **Never reorder the children of `<p:presentation>`.** pptxgenjs writes `<p:notesMasterIdLst>` right after `<p:sldIdLst>` and points both masters at one theme part. PowerPoint reads that happily — move the element and the same deck becomes unopenable.
- **Icons:** render `react-icons` to SVG (`ReactDOMServer.renderToStaticMarkup`), rasterize with `sharp` at ≥256px, and insert via `addImage({ data: "image/png;base64," + buf.toString("base64") })` — the `image/png;base64,` prefix is required (`react-icons`, `react`, `react-dom`, and `sharp` are preinstalled — `npm install react-icons react react-dom sharp` only if a require fails).
Pick layouts first: `python scripts/thumbnail.py template.pptx template-thumbs` writes a labeled grid of every slide and prints the file(s) it created — `template-thumbs.jpg`, split into `template-thumbs-N.jpg` past 12 slides. **Always pass that second argument, named after the deck.** It defaults to `thumbnails`, so two decks thumbnailed in one directory silently overwrite each other's grids — the first deck's are simply gone (template analysis only — visual QA needs the full-resolution renders from [Converting to Images](#converting-to-images); it only accepts `.pptx`, so copy a `.potx` to a `.pptx` name first). Use it with `markitdown` to map each content section onto a template slide, and vary the layouts — don't put every section on the same title-and-bullets slide.
- **Do all structural work — add, delete, reorder — before editing any slide's content.** `add_slide.py` copies a slide file verbatim, so duplicating after you edit clones the edited content; and `clean.py` deletes any slide missing from `<p:sldIdLst>`, including one you just wrote.
- **Never copy a slide file by hand** — `add_slide.py` does every registration a new slide needs and reports what it made (`Created ppt/slides/slide17.xml from slide2.xml`). It also works directly on a file: `add_slide.py deck.pptx slide2.xml -o out.pptx` — **pass `-o`, or it rewrites the input deck in place.** A duplicated slide still *references* its source's chart/SmartArt/embedded-object parts rather than cloning them, so editing one slide's chart changes the other's.
- **If you use `python-pptx`**, three things it won't do: duplicate a slide (its only entry point is `add_slide(layout)`), preserve formatting through `text_frame.text = "..."` (that collapses the paragraph to a single unstyled run — assign `run.text` instead), or read the SVG/EMF most template art uses (`add_picture` raises `UnidentifiedImageError`).
- Legacy `.ppt` must be converted first: `python scripts/office/soffice.py --headless --convert-to pptx file.ppt`. `.potx` templates unpack and pack identically — keep the `.potx` extension on the output.
- To reuse a template icon or image, duplicate a slide or layout that already contains it.
PPTX creation, editing, and analysis
A `.pptx` is a ZIP archive of XML files. Choose your approach by task:
| Task | Approach |
|---|---|
| **Create** a new deck | Write a `pptxgenjs` script — see gotchas below |
| **Edit** an existing deck, or build from a template | unzip → edit `ppt/slides/slideN.xml` → zip |
| **Read** content | `markitdown deck.pptx` (one block per slide under `<!-- Slide number: N -->` markers); visual grid: `python scripts/thumbnail.py deck.pptx` |
Scripts
Paths are relative to this skill's directory. Everything else is plain Python, `node`, or shell.
| Script | What it does |
|---|---|
| `scripts/thumbnail.py deck.pptx [prefix]` | Labeled grid of every slide, for picking template layouts. `.pptx` only. Pass `prefix` — it defaults to `thumbnails`, which overwrites the grids of any other deck done in the same directory |
| `scripts/add_slide.py unpacked/ slide2.xml [--after slideN.xml]` | Duplicate a slide (or a `slideLayoutN.xml`) with all the package bookkeeping. Also takes a `.pptx` directly with `-o out.pptx` |
| `scripts/clean.py unpacked/` | Delete slides, media, and rels no longer referenced. Run **after** `<p:sldIdLst>` is final |
| `scripts/office/validate.py deck.pptx [--original src.pptx]` | Schema, relationship, content-type, chart and slide checks; each failure names its fix. Pass `--original` for any template-derived deck — it baselines the schema checks against the template, so the template's own XSD errors don't read as yours |
| `scripts/office/soffice.py --headless --convert-to pdf deck.pptx` | LibreOffice wrapper — bare `soffice` hangs in this sandbox |
Creating with pptxgenjs — gotchas
`pptxgenjs` is preinstalled — do not run `npm install` first; write the script and `require('pptxgenjs')` directly. Only if that require fails: `npm install pptxgenjs`. The model knows the API; these are the footguns:
- **Set `pres.layout` before adding slides.** The default canvas is `LAYOUT_16x9` = **10" × 5.625"**, not 13.3" wide. Coordinates past the edge are written, not clamped — the shape just isn't on the slide. (`LAYOUT_WIDE` is 13.3" × 7.5".)
- **Hex colors: never `#`, never 8 digits.** `color: "FF0000"`. Both `"#FF0000"` and alpha baked into the hex (`"00000020"`) **corrupt the file**. For translucency: `transparency: 0-100` on fills and images, `opacity: 0.0-1.0` on shadows — each is silently ignored on the other.
- **pptxgenjs mutates option objects in place** (converts values to EMU on first use). Never share one `shadow`/options object across two `add*` calls — build a fresh object each time.
- **Shadow `offset` must be ≥ 0** — a negative offset corrupts the file. To cast a shadow upward, use `angle: 270` with a positive offset.
- **`letterSpacing` is silently ignored** — the real option is `charSpacing`.
- **Lists:** `bullet: true` on each item, never a literal `•` (renders double bullets). Set `breakLine: true` on every array item except the last. Space bulleted paragraphs with `paraSpaceAfter`, not `lineSpacing` (huge gaps).
- **One `new pptxgen()` per output file** — never reuse an instance.
- **`rectRadius` only works on `ROUNDED_RECTANGLE`**, not `RECTANGLE`.
- **Gradient fills aren't supported** — use a gradient image as the background instead.
- **Text boxes have built-in internal padding** — set `margin: 0` whenever text must align with a shape, line, or icon at the same x.
- **Speaker notes go in `slide.addNotes("...")`** (plain text, once per slide), never in a text box on the slide.
- **Keep charts native.** Use `addChart()` for everything PowerPoint can chart (pass an array of `{type, data, options}` for combos). For PowerPoint-native features the library doesn't expose (trendlines, error bars), compute the extra series yourself or post-process the generated OOXML — do not fall back to a rendered image. Only chart types PowerPoint has no native form for (Sankey, network, chord) go in as images.
- **Default charts render bare** — no title, no data labels, dated palette. Set `showTitle` + `title`, `showValue: true` + `dataLabelPosition`, `chartColors: [...]` from your palette, and quiet the frame (`catAxisLabelColor`/`valAxisLabelColor`, `valGridLine: { color, size }`, `catGridLine: { style: "none" }`, `showLegend: false` for a single series).
- **On a stacked bar or column chart, `dataLabelPosition` must be `ctr`, `inEnd`, or `inBase`.** `outEnd` **corrupts the file**.
- **A combo series using `secondaryValAxis`/`secondaryCatAxis` needs both `valAxes` and `catAxes` on the chart options, two entries each.** Without them pptxgenjs writes axis *ids* it never declares, and PowerPoint **discards that chart** and reports the file as corrupt. Supplying only `valAxes` is not enough.
- **After `writeFile()`, run `python scripts/office/validate.py deck.pptx`.** It reports the two chart faults above and the slide-XML defects PowerPoint refuses, and names the fix for each. Fix them in your generator, not by hand-editing the packed XML.
- **Never reorder the children of `<p:presentation>`.** pptxgenjs writes `<p:notesMasterIdLst>` right after `<p:sldIdLst>` and points both masters at one theme part. PowerPoint reads that happily — move the element and the same deck becomes unopenable.
- **Icons:** render `react-icons` to SVG (`ReactDOMServer.renderToStaticMarkup`), rasterize with `sharp` at ≥256px, and insert via `addImage({ data: "image/png;base64," + buf.toString("base64") })` — the `image/png;base64,` prefix is required (`react-icons`, `react`, `react-dom`, and `sharp` are preinstalled — `npm install react-icons react react-dom sharp` only if a require fails).
Editing existing decks and templates
Pick layouts first: `python scripts/thumbnail.py template.pptx template-thumbs` writes a labeled grid of every slide and prints the file(s) it created — `template-thumbs.jpg`, split into `template-thumbs-N.jpg` past 12 slides. **Always pass that second argument, named after the deck.** It defaults to `thumbnails`, so two decks thumbnailed in one directory silently overwrite each other's grids — the first deck's are simply gone (template analysis only — visual QA needs the full-resolution renders from [Converting to Images](#converting-to-images); it only accepts `.pptx`, so copy a `.potx` to a `.pptx` name first). Use it with `markitdown` to map each content section onto a template slide, and vary the layouts — don't put every section on the same title-and-bullets slide.
```bash
python3 -c "import sys,zipfile; zipfile.ZipFile(sys.argv[1]).extractall('unpacked')" deck.pptx
python scripts/add_slide.py unpacked/ slide2.xml --after slide2.xml # duplicate a slide (or slideLayoutN.xml); prints the new slide's path
reorder / delete slides = edit <p:sldIdLst> in ppt/presentation.xml
python scripts/clean.py unpacked/ # after deletions: removes orphaned slides, media, rels