Deck Builder

Deck & Doc Builder

A battle-tested workflow for producing beautiful, consistent slide decks and Google Docs as code, iterating fast, and shipping them straight into Google Drive without the link ever changing.

The golden rule: generate → render to image → look at it → fix → upload. Never claim a slide looks right without rendering it and viewing the PNG.

When to use

• "Make/update a deck / PPT / briefing / one-pager" (customer, exec, internal).
• "Turn these notes / meeting minutes into a clean Google Doc."
• "Put this into our Drive folder" / "update the slides I shared earlier."
• Anything where layout quality + brand consistency matter.

The loop (do this every iteration)

1. Generate the artifact with code (never hand-place by guessing):
   • Slides: a python-pptx script using scripts/deck_helpers.py.
   • Docs: rich HTML → uploaded as a Google Doc (see reference.md).
2. Render to PNG and LOOK: scripts/render.sh deck.pptx 3 5 renders pages 3–5. Read the PNGs. Check overflow, alignment, color, crops, fit.
3. Fix the code and re-render until it's right.
4. Upload / update to Drive with scripts/gslides.py:
   • First time: create (returns a fileId; save it to a dotfile).
   • Every later iteration: PATCH the same fileId → the share link is stable.
5. Render the uploaded result once more (export Slides/Doc → PDF → PNG) to confirm Google's conversion matches your intent.

Render is cheap and the only source of truth. A tight loop of small edits + re-render beats trying to get it perfect blind.

Slides: the design system (scripts/deck_helpers.py)

• 16:9 canvas 13.333" × 7.5", blank layout, everything absolutely positioned.
• Google palette (BLUE/RED/YELLOW/GREEN + grey ramp) as named constants.
• Core helpers (see file for signatures):
  • txt(...) — textbox; **bold** markers inside the string toggle bold, \n splits paragraphs. This is the workhorse.
  • card(...) rounded rectangle, bar(...) solid rect (also used as accent strips / thin connector lines), hline(...) connector, dots(...) the Google 4-dot motif, pic(...) image with crop-to-fill (no distortion), video(...) embedded mp4 with poster, scrim(...) dark alpha overlay, title(...) page title with optional 21:9 hero image + scrim, notes(...).
• Patterns that read well: KPI cards row, horizontal bar chart drawn with bar(), alternating timeline, 2×N card grid, comparison table drawn with txt+hline, a colored callout band at the bottom for the "so what".
• Keep one slide = one idea. Put the takeaway in a colored band.

Charts

• For accurate data (pie/donut/bars that must match a table), draw with matplotlib and embed the PNG — do not eyeball. Use a CJK font (Noto Sans CJK) for Chinese labels. Save as a square transparent PNG so pic() crop-to-fill doesn't clip outer labels. See reference.md.
• Make the chart numbers equal the table numbers. Inconsistent totals are the #1 thing reviewers catch.

Imagery

• Generate decorative/concept images with Nano Banana 2 (gemini-3.1-flash-image on Vertex). Prompt for clean, no-text, no-logo, brand-neutral visuals. Good for hero strips, concept diagrams, section art. Code in reference.md.
• Real product/brand images beat generated ones — pull from the user's Drive or the official site when authenticity matters.
• User-pasted images (screenshots they drop in chat) are NOT on disk as files — they're base64 in the session JSONL. Extract them with the snippet in reference.md (match by the WxH shown on the attachment chip). Don't say "I can't access the image"; go get it.

Google Drive / Workspace (scripts/gslides.py)

• Auth: ADC at ~/.config/gcloud/application_default_credentials.json must have drive + presentations scope; every request needs the X-Goog-User-Project header. (See "Setup" below.)
• PPTX → Google Slides: resumable upload with mimeType: application/vnd.google-apps.presentation (Drive auto-converts).
• HTML → Google Doc: same, application/vnd.google-apps.document. Google Docs import respects colored headings, bgcolor table cells, callout boxes (single-cell tables), and base64 data: images — verified. This is how you get a pretty Doc, not a plain one.
• Link-stable iteration: keep the fileId and PATCH it on every update (uploadType=resumable, method=PATCH). The URL stays the same so anyone you shared it with always sees the latest.
• Export for self-check: export the Slides/Doc to PDF, then PNG, and look.

Content principles (for briefings)

• State outcomes plainly; verify before saying "done" (render it).
• Don't over-commit on the customer's behalf; ground vague claims in real, sourced numbers, and label estimates as estimates.
• Match the audience: internal vs customer-facing decks have different rules about citing sources, pricing, and roadmap specificity — confirm which.
• Strong logic > volume. Prefer a "problem → ask → how we help → decision" mapping table over long prose.

Setup (first run / new user)

1. Auth (ADC). This skill uploads / creates / PATCHes files, so drive and presentations must be FULL (write) scopes — the .readonly variants cannot write. (No documents scope needed: Google Docs are created/updated via Drive's HTML→Doc import, which only needs drive write.)

   gcloud auth application-default login --scopes=openid,email,\
   https://www.googleapis.com/auth/cloud-platform,\
   https://www.googleapis.com/auth/drive,\
   https://www.googleapis.com/auth/presentations
   

   drive(write) creates/updates both Slides and Docs; presentations(write) is for any Slides-API edits; cloud-platform covers Vertex (Nano Banana) and Slides/Docs API reads.
2. Project defaults to cloud-llm-preview1 for both Drive calls (X_GOOG_USER_PROJECT in gslides.py) and Nano Banana (Vertex PROJECT in reference.md). If you can access that project, change nothing; else set yours.
3. pip install python-pptx pillow matplotlib; have libreoffice + poppler (pdftoppm, pdfinfo) on PATH for the render loop.

Files in this skill

• scripts/deck_helpers.py — the python-pptx design-system library (import it).
• scripts/gslides.py — Workspace: token, upload→Slides/Doc, PATCH, export PDF.
• scripts/render.sh — pptx/pdf → PNG pages for visual self-check.
• reference.md — Nano Banana gen, matplotlib donut, pasted-image extraction, Google-Doc HTML styling recipes, gotchas.