Activation Contract
Use this skill by default whenever the user asks, in plain words, for a UI design, mockup, screen, landing page, or visual directions, or iterates on artboards under design/. Do not use it to implement production code in the project's stack.
The /gentle:design commands are optional shortcuts: every action also works from a plain request, through this skill and the gentle_design tool (list, open, stop, implement, handoff).
Hard Rules
- Every artboard is one self-contained HTML file: inline CSS, JS, and SVG; system font stacks only. Never reference external URLs, CDNs, remote fonts, images, or scripts.
- Use realistic content for the audience; no lorem ipsum or placeholder names.
- Accessible markup: semantic elements and landmarks, WCAG AA contrast, visible focus styles,
prefers-reduced-motion respected for any motion.
- When
design/system.md exists, read it first and use only its tokens and component rules; run the Self-check from "Design system sync" before finishing any artboard.
- Ask at most one clarifying question, and only when the brief lacks the goal or the content.
- Iterating edits only the targeted artboard. Never rewrite the others.
Decision Gates
| Situation | Action |
|---|
| New brief | Write N clearly different directions (3 by default, or the number asked) to a new design/<slug>/ |
| Feedback on one artboard | Edit that file only; keep its manifest entry, update tradeoff if it changed |
| "Save and try a different approach" | Add a new artboard with the next NN; keep previous ones; append it to the manifest |
| User wants to tune values (spacing, color, type scale) | Add sliders or controls in the artboard plus a "Copy as prompt" button that copies the chosen values as a prompt |
design/<slug>/ already exists for a new brief | Pick a new slug; never overwrite another design |
| A message carries design comments, or the user asks to apply them | Follow "Canvas comments" below |
/gentle:design sync, or the user asks to capture the project's design system | Follow "Design system sync" below |
| The user asks to show, stop, or list designs, or to implement an artboard | Call the gentle_design tool (open, stop, list, or implement with <slug>/<artboard>); follow the handoff text implement returns, and report progress with action "handoff": status: "in_progress" when you start, status: "implemented" when done, with previewUrl set to the running app's loopback URL when one is running |
Before designing
Run this gate before every new brief: call the gentle_design tool with action: "list", then:
list reports | Action |
|---|
system.exists false and designSources present | Run "Design system sync" first, tell the user in one line that you synced the project's design system, then design with it |
No designSources | Skip the sync and design freely |
system.staleSources present | Name those sources, say design/system.md may be outdated, and offer to sync again before designing; re-sync only with the user's OK, and never use the stale tokens silently |
Execution Steps
- Take the brief: goal, layout, content, audience.
- Choose a kebab-case slug from the brief.
- Make the directions differ in structure or visual strategy, not only in color. Label each with the tradeoff it makes.
- Write
design/<slug>/NN-<name>.html per artboard (01-…, 02-…; kebab-case name).
- Write
design/<slug>/design.json:
{
"title": "Pricing page",
"brief": "Pricing page for a note-taking app aimed at students",
"feature": "odd/tasks/pricing-page.md",
"artboards": [
{ "file": "01-comparison-table.html", "title": "Comparison table", "tradeoff": "Dense and scannable; weaker emotional pull", "width": 1440, "height": 900 },
{ "file": "02-single-plan-hero.html", "title": "Single plan hero", "tradeoff": "Strong focus; hides plan differences", "width": 1440, "height": 900 }
]
}
- Set
width/height to the artboard's intended viewport in CSS pixels; keep the manifest in sync with the files on every change. Fields: title, brief, optional feature, and artboards[] with file, title, tradeoff, width, height.
- ODD link: when the design comes from a tracked ODD feature (an existing
odd/tasks/<feature>.md for the current work), set feature to that path and append one entry to that document's ## Log naming design/<slug>/ and its artboards. When an artboard of that design is handed off to implement, the Log entry also names the chosen artboard (the one handed off; list reports it as Chosen) and that the others are alternatives. For small untracked work, omit feature and leave the design standalone; never create a feature document just to link it.
- After writing or changing artboards, call the
gentle_design tool with action: "open" and the slug, unless the user said not to. When a canvas tab is already open it refreshes that tab instead of opening a new one, so call it after every change. Report the URL it returns.
Design system sync
- Read only, and never edit project source. Sources: CSS custom properties (
:root, @theme, [data-theme]), the Tailwind config or v4 @theme, component library folders, existing token files, and the fonts they declare.
- Write
design/system.md: colors (token name, value, usage), typography, spacing, radius, shadows, and component rules. Each entry names its source path. Record only values found in the sources.
- Write
design/system.html: one self-contained artboard, 1440 px wide, that renders those tokens (swatches, type scale, spacing, radius, shadows) and the core components, under the same no-external-URL rules. The canvas shows it as the first board of every design.
- When no design sources exist, say so and propose a minimal starter system for the user to accept; never present invented values as project tokens.
- Self-check, for every artboard you finish while
design/system.md exists: list the colors and font families the artboard uses, compare them with the system tokens, and fix every deviation before you report.
Canvas comments
Comments from the canvas are stored in design/<slug>/comments.json; the session also receives them as messages that name each comment id.
- Read the open comments with the
gentle_design_comments tool (action: "list", optional slug and file). Without the tool, read design/<slug>/comments.json and use the entries whose status is "open".
- Apply each comment by editing only the artboard in its
file; use selector and excerpt to find the element. When a comment has a screenshot, look at it first: it arrives attached to the comment message, or open design/<slug>/<screenshot> with the read tool. It shows what the user saw, often a transient animation or transition state that the static artboard does not show.
- Mark each applied comment resolved with the tool (
action: "resolve", slug, ids). Without the tool, set its status to "resolved" and resolvedAt to the current ISO time, keeping every other entry and field as is. Leave comments you did not apply open, and say why.
The file format, for agents that only have file access:
{
"version": 1,
"comments": [
{ "id": "k3x9p2ab", "file": "02-bold.html", "selector": "body > header > h1", "excerpt": "Ship faster", "comment": "Make the headline shorter.", "createdAt": "2026-10-26T10:00:00.000Z", "status": "open", "sentAt": null, "resolvedAt": null },
{ "id": "m7q2w9cd", "file": "02-bold.html", "selector": "#cta", "excerpt": "Start", "comment": "The button jumps during the hover transition.", "screenshot": ".screenshots/m7q2w9cd.png", "createdAt": "2026-10-26T10:05:00.000Z", "status": "open", "sentAt": null, "resolvedAt": null }
]
}
screenshot is optional: a path relative to the design folder, under .screenshots/, present only when the user attached an image.
Never delete or reorder entries, and keep the file valid JSON: the canvas refuses to overwrite a file it cannot parse.
Output Contract
Return: the slug, each artboard file with its title and tradeoff, which files changed in this turn, the comment ids resolved in this turn, and any open question. Give the canvas URL from step 8, or mention that /gentle:design open <slug> shows the canvas when you did not open it. For a sync, return the source paths read, the token counts per group, and whether the system is a proposed starter; after an automatic sync from "Before designing", say it ran and report it the same way.
References
design/system.md in the project, when present — the design tokens to follow.