Architecture Canvas

Produce an interactive architecture diagram as a single self-contained index.html: a canvas viewer with pan/zoom/pinch, click-to-isolate focus with a readout panel, keyboard shortcuts, shareable view URLs, and 2× PNG export. You never write viewer code — you author a scene (pure data: planes, bands, boxes, edges, labels) and the bundled scripts assemble and check it.

The pipeline:

understand the architecture → write scene.js → validate → build → (publish)

Step 1 — Understand the architecture first

The diagram is only as good as the analysis. Before any drawing, produce a short architecture brief (in your working notes, or shown to the user if they should confirm it):

• Planes/layers (4–7), in causal top-to-bottom order — who acts, through what surface, on what abstractions, executed where. Name each plane and its one-line role.
• Components (15–25 total): for each — its plane, whether it's an owned abstraction (dashed) or swappable infra / app surface (solid), 1–2 facts, and the one non-obvious thing about it (this becomes the italic footnote).
• Flows (10–20 meaningful edges): the main pipeline, plus feedback loops and cross-cutting flows.
• The thesis: a 3–5 word pipeline strapline (e.g. browse → price → order → fulfil → learn) and a one-sentence subtitle.

Where the architecture comes from depends on what you're given:

• A codebase — explore it (package layout, entry points, deploy configs, existing docs/READMEs). Spawn an Explore agent for large repos.
• An architecture doc — read it, but verify surprising claims against the code when both exist.
• A description — use it as-is; ask only if the layering is genuinely ambiguous.

Step 2 — Author the scene

Read references/scene-format.md (data model, coordinate math, layout recipe) and skim examples/shoply-scene.js (the canonical example scene). Then write a scene.js next to your intended output defining the nine constants: W, H, PLANES, BANDS, BOXES, EDGES, TEXTS, SWATCHES, CHIPS.

Layout mechanically, top to bottom, using the recipe's numbers — title block at the top, ~5 bands (merge related planes into a neutral multi-column band rather than stacking 7 thin ones), generous boxes that fill their band's width, edges routed orthogonally with long feedback flows in the side gutters, footnotes at the bottom, then set H.

Write scene.js inside the artifact folder (next to the future index.html) so nothing strays outside the publishable directory, and write its comments about this architecture — don't carry over the example's Shoply-specific commentary.

Step 3 — Validate, then build

node <skill-dir>/scripts/validate.js scene.js

Fix every ERROR (dangling ids, boxes outside bands, overlaps, text overflow) and take WARNings seriously — they're usually real. Re-run until clean, then:

node <skill-dir>/scripts/build.js --scene scene.js --out <slug>/index.html \
  --title "Acme — platform architecture" \
  --kicker "ACME — PLATFORM ARCHITECTURE" \
  --sub "<b>ingest</b> → <b>process</b> → <b>serve</b>" \
  --slug acme-architecture

--sub is the plate strapline (small HTML, <b> for the stage names). Output into its own folder with index.html at the root — that folder is the publishable artifact.

If browser tooling is available (Playwright MCP, open), load the file once and screenshot it — check nothing collides and the story reads top-to-bottom. Don't skip validation in favour of eyeballing; do both when you can.

Step 4 — Publish to artifact.cafe (when the user wants it shared)

If the user asked to publish/share/review the canvas, invoke the artifact-cafe skill and follow it — it handles login/workspace choice, --title/--notes, and returns the review URL. Point it at the folder containing index.html. If the user didn't ask, offer it as a follow-up instead of publishing unprompted.

Quality bar

• Ownership semantics stay honest: dashed = owned abstraction, solid = swappable infra or app surface. This distinction is the diagram's argument.
• Adjacent columns get well-separated hues; every plane colour comes from the recommended list in the reference.
• Readout about text is written for a newcomer — one crisp sentence per box.
• The diagram is an orientation map, not an inventory: fewer, better boxes.