Design Brief Skill

Parse a structured design brief into a concrete DESIGN.md and optional visual preview. Agent, follow this workflow exactly.

Background

The 8 dimensions in this skill are derived from analysis of the 71 design systems bundled with Open Design. Every DESIGN.md in design-systems/ resolves at minimum: color palette, accent, typography, display font, layout model, and component style. We distilled these into 8 orthogonal dimensions that cover the decisions a designer makes before any pixel is placed. Mood and density were added because they are the two most common sources of ambiguity in natural language briefs ("make it clean" means different things to different people).

Dimensions intentionally excluded from the brief level: animation timing, responsive strategy, and accessibility contrast. These are enforced at the template level by individual skills (e.g., saas-landing handles its own responsive logic), though the generated DESIGN.md includes sensible breakpoint defaults for downstream consumption.

1. Accept input

The user provides a design brief in one of two formats:

Option A: I-Lang structured brief

[PLAN:@DESIGN|type=saas_landing]
  |palette=navy_and_white|accent=coral
  |typography=inter|display=space_grotesk
  |layout=single_column|max_width=1200px
  |mood=professional_minimal
  |density=spacious|section_gap=96px
  |hero=headline+subhead+cta
  |sections=features,pricing,testimonials,footer
  |exclude=animations,parallax,gradients
  |responsive=mobile_first

Option B: Natural language

"I need a landing page for a developer tool. Clean, minimal, dark mode. Inter font. No flashy animations."

If the user provides Option B, convert it to the structured format using the mapping table below, then proceed. Identify every dimension explicitly stated and flag dimensions that were left unspecified.

Natural language → I-Lang mapping

For each sentence in the natural language input, identify dimension keywords and map to the closest structured value:

Natural language phrase	Dimension	I-Lang value
"dark mode", "dark theme"	palette	monochrome_dark
"light", "white background"	palette	light_clean
"earthy", "warm tones"	palette	earth_tones
"pop of color", "vibrant"	accent	electric_blue (default) or coral
"subtle accent"	accent	muted_sage (default) or slate
"clean", "minimal", "simple"	mood	professional_minimal
"playful", "fun", "friendly"	mood	playful
"bold", "brutalist", "raw"	mood	brutalist
"editorial", "magazine-like"	mood	editorial
"spacious", "lots of whitespace"	density	spacious
"compact", "dense", "information-rich"	density	compact
"Inter", "system font"	typography	inter (default) or system_ui
"serif", "traditional"	typography	georgia (default) or playfair
"monospace", "code-like"	typography	jetbrains_mono
"no animations", "static"	exclude	animations
"no gradients"	exclude	gradients
"no stock photos"	exclude	stock_photos
"single page"	layout	single_column
"two columns", "sidebar"	layout	two_column
"mobile first"	responsive	mobile_first

When a phrase maps to multiple dimensions (e.g. "clean dark landing page" → mood=professional_minimal + palette=monochrome_dark + layout=single_column), resolve each dimension independently. When multiple values are listed for a single mapping, the first is the default; the agent may select the alternative only if surrounding context strongly favors it.

2. Validate dimensions

Every design brief must resolve these 8 dimensions. If any are missing from the input, select sensible defaults using the rules in Section 2.2.

The values listed below form a closed vocabulary. Only values in this table have concrete token mappings in Section 2.1. If the user provides a value not listed here, the agent must prompt for clarification rather than guessing.

#	Dimension	Key	Example values
1	Color palette	palette	navy_and_white, earth_tones, monochrome_dark, light_clean
2	Accent color	accent	coral, electric_blue, emerald, muted_sage
3	Body typography	typography	inter, system_ui, dm_sans, georgia
4	Display typography	display	space_grotesk, clash_display, same_as_body, playfair
5	Layout model	layout	single_column, two_column, asymmetric
6	Mood	mood	professional_minimal, playful, brutalist, editorial
7	Density	density	compact, balanced, spacious
8	Constraints	exclude	animations, gradients, stock_photos, carousel

2.1 Symbolic → concrete token resolution

Each symbolic value maps to concrete design tokens. The agent must resolve these before writing DESIGN.md:

Symbolic value	Concrete tokens
palette=navy_and_white	Background: #0F172A, Surface: #1E293B, Text: #F8FAFC, Secondary: #94A3B8
palette=monochrome_dark	Background: #09090B, Surface: #18181B, Text: #FAFAFA, Secondary: #A1A1AA
palette=light_clean	Background: #FFFFFF, Surface: #F8FAFC, Text: #0F172A, Secondary: #64748B
palette=earth_tones	Background: #FFFBEB, Surface: #FEF3C7, Text: #451A03, Secondary: #92400E
accent=coral	Accent: #F97316, Hover: #EA580C
accent=electric_blue	Accent: #3B82F6, Hover: #2563EB
accent=emerald	Accent: #10B981, Hover: #059669
accent=muted_sage	Accent: #84A98C, Hover: #6B8F73
accent=slate	Accent: #64748B, Hover: #475569
typography=inter	Body: Inter, 400, 1rem/1.6
typography=system_ui	Body: system-ui, 400, 1rem/1.6
typography=dm_sans	Body: DM Sans, 400, 1rem/1.6
typography=georgia	Body: Georgia, 400, 1.125rem/1.7
display=space_grotesk	Display: Space Grotesk, 700, clamp(2rem, 5vw, 3.5rem)
display=clash_display	Display: Clash Display, 700, clamp(2rem, 5vw, 3.5rem)
display=playfair	Display: Playfair Display, 700, clamp(2rem, 5vw, 3.5rem)
display=same_as_body	Display inherits body font family, weight 600
density=compact	Section spacing: 48px, Content padding: 16px/24px
density=balanced	Section spacing: 72px, Content padding: 24px/40px
density=spacious	Section spacing: 96px, Content padding: 24px/48px

Symbolic values not in this table are not valid. If the user provides an unrecognized value (e.g., palette=ocean_blue), the agent must prompt for clarification: "I don't recognize palette=ocean_blue. Did you mean navy_and_white, monochrome_dark, light_clean, or earth_tones?"

2.2 Default resolution rules

When a dimension is unspecified, defaults are selected based on mood compatibility:

Unspecified dimension	Default rule
palette	If mood=editorial → light_clean. If mood=brutalist → monochrome_dark. Otherwise → light_clean.
accent	If palette is dark → coral. If palette is light → electric_blue.
typography	Always → inter (highest cross-platform legibility).
display	If mood=editorial → playfair. If mood=brutalist → space_grotesk. Otherwise → same_as_body.
layout	Always → single_column (safest responsive default).
mood	Always → professional_minimal (least opinionated).
density	Always → balanced.
exclude	Always → none (no constraints unless specified).

If mood is also unspecified, all defaults fall back to the safe neutral set: palette=light_clean, accent=electric_blue, typography=inter, display=same_as_body, layout=single_column, mood=professional_minimal, density=balanced, exclude=none.

3. Generate DESIGN.md

This skill generates a new DESIGN.md from scratch based on the resolved brief dimensions. If a DESIGN.md already exists in the working directory, the agent should ask the user whether to overwrite or skip.

Produce a DESIGN.md following Open Design's 9-section convention. All color hex values, font stacks, and spacing values must come from the resolved tokens in Section 2.1 — do not invent values outside the resolution table.

# [Project Name] Design System

## Visual Theme & Atmosphere
- Mood: [resolved from mood]
- Feel: [derived from mood — e.g., professional_minimal → "Clean, confident, restrained"]
- References: [if mood=editorial → "Magazine layouts, Monocle, Cereal"; if mood=brutalist → "Exposed structure, raw typography"]

## Color Palette & Roles
- Background: [resolved from palette]
- Surface: [resolved from palette]
- Text primary: [resolved from palette]
- Text secondary: [resolved from palette]
- Accent: [resolved from accent]
- Accent hover: [resolved from accent]

## Typography Rules
- Display: [resolved from display], 700, clamp(2rem, 5vw, 3.5rem)
- Body: [resolved from typography], 400, 1rem/1.6
- Mono: JetBrains Mono, 400, 0.875rem

## Component Stylings
- Buttons: [if mood=playful → "rounded-full", otherwise → "rounded-md"], accent bg, contrast text
- Cards: surface bg, subtle border, 12px radius
- Inputs: [if mood=brutalist → "thick border", otherwise → "transparent bg, bottom border"]

## Layout Principles
- Max width: 1200px
- Grid: [resolved from layout]
- Section spacing: [resolved from density]
- Content padding: [resolved from density]

## Depth & Elevation
- Shadows: [if mood=brutalist → "hard 4px offset", if mood=professional_minimal → "none", otherwise → "subtle sm"]
- Borders: 1px solid [derived from palette, 8% opacity of text color]

## Do's and Don'ts
- DO use the declared color tokens exclusively.
- DO maintain consistent section spacing.
- DO ensure all text meets WCAG AA contrast ratio.
- DON'T invent colors outside the palette.
- DON'T add decorative shadows unless Depth & Elevation allows them.
- DON'T use more than 2 display/body typefaces (monospace is a utility face for code and data — it does not count toward this limit).

## Responsive Behavior
- Breakpoints: 640px (sm), 768px (md), 1024px (lg), 1280px (xl)
- Mobile: single column, stack all sections vertically
- Tablet: allow 2-column feature grids
- Desktop: full layout with max-width constraint
- Images: fluid, max-width 100%, maintain aspect ratio

## Agent Prompt Guide
- Do NOT invent colors outside this palette.
- Do NOT add box-shadows unless specified above.
- Accent color appears maximum 3 times per viewport.
- All interactive elements need :focus-visible outline.
- [if exclude contains items → list each as "Do NOT use {item}."]

4. Generate brief-preview.html

Create a single HTML file that visually renders the resolved design tokens. The preview must contain these 4 sections in order:

1. Color palette swatches — A horizontal row of rectangles, each showing one color from the Color section. Label each with its role (Background, Surface, Text, Accent) and hex code.
2. Typography specimens — Three text blocks showing Display, Body, and Mono fonts at their declared sizes. Use a sample sentence ("The quick brown fox...") for each.
3. Spacing ruler — A visual ruler or stacked bars showing section spacing and content padding values, labeled with their px values.
4. Component preview — Render 2–3 live components (a primary button, a card with title/body, a text input) using the resolved tokens. These should be functional HTML/CSS, not screenshots.

Style the preview itself with the resolved design system tokens (background color, font, spacing). The preview should look like a design system documentation page.

5. Report unspecified dimensions

At the end of output, list any dimensions the user did not specify and the defaults that were applied, including the rule that selected each default:

Dimensions resolved from defaults:
- display: set to "same_as_body" (rule: mood=professional_minimal → same_as_body)
- density: set to "balanced" (rule: static fallback, no spacing preference given)
- exclude: set to "none" (rule: no constraints unless specified)

This transparency prevents silent assumptions from propagating into the final design.