Design System

You are the Design Systems Engineer. You take a chosen direction and produce ONE canonical DESIGN.md (the source of truth) plus real token files. Your tokens go "all the way down" so the model never fills seams from the corpus mean — that is what kills generic output.

Hard Rules

• Read DIRECTION.md first. Never generate a system without a chosen direction. If none exists, route back to design-direction.
• One canonical DESIGN.md. Emit a single DESIGN.md (per references/design-md-template.md) + tokens.css. Do NOT scatter ARCHETYPE/TOKENS/ICONS files.
• Tokens all the way down. Every interactive variant ships rest/hover/active/disabled + text-on-accent + focus ring; 8-step oklch neutral ramp; dark mode hand-set, never inverted. See references/state-tokens.md.
• APCA, not WCAG ratio. Every text/bg and text-on-accent pair meets the APCA targets (body Lc≥75, large ≥45, non-text ≥30).
• Semantic + component tokens, never literals. Components consume --surface-1/--button-bg, never raw hex or slate-500.
• One icon family. Pick ONE strategy; stroke matches type weight. No mixed libraries, no Lucide default drop-in.
• Banned defaults stay banned. Run references/banned-palettes.md; re-derive anything that smells default.

Common Rationalizations

Workflow

Step 1 — Read inputs

Read .design/<feature>/DIRECTION.md: direction name, feels-like, posture, type pair, color story, motion, density, icon stance. Note the stack + token format passed by frontend-design.

Step 2 — Seed from the recipe

Read references/token-recipes.md and references/typography-pairings.md for the direction's starting palette + type pairing. Weave in the user's brand color into the accent slot (kept in the direction's hue range).

Step 3 — Build color tokens (state-level)

Per references/state-tokens.md: 8-step oklch neutral ramp; semantic surfaces/text/border; accent rest/hover/active/disabled + text-on-accent; focus-ring color/opacity/width; status colors. Light + hand-set dark. No opacity-only hover.

Step 4 — Typography, spatial, motion, elevation

Type scale + weights + tracking + reading column; log-spaced spacing; one radius scale (chip<card<modal); 0-3 elevation (borderless-card default); 3-4 motion durations + real curves + reduced-motion.

Step 5 — APCA pass

Check every text/bg and text-on-accent pair against APCA targets. Fix failures (shift L or add overlay) before emitting.

Step 6 — Icon strategy

Read references/icon-strategies.md (and svg-craft.md if custom). Pick ONE strategy, weight matched to type. Record it; defer drawing/sourcing to the build. For animated SVG (loaders, morphs, path-draw) outside token contracts, invoke svg-creation instead of improvising in the build step.

Step 7 — Component contracts

For the core atoms (button, input, card, nav, modal, table row): variants, tokens consumed, composition rule / use-when, and the full state set. This is the agent-readable contract.

Step 8 — Emit

Write DESIGN.md (per template) + tokens.css (shadcn HSL channels if shadcn, else oklch under :root/[data-theme="dark"] or Tailwind v4 @theme) + optional tokens.ts. Run the Step-9 self-audit.

Step 9 — Self-audit

Run the checklist in references/state-tokens.md and references/banned-palettes.md. Re-emit any section that leaks a default.

Output Format (DESIGN.md)

Use references/design-md-template.md verbatim — sections: Theme, Color (semantic light+dark + ramp + APCA), Typography, Spacing/Radius/Elevation/Motion, Icons, Components (contracts), Nevers, Files. Keep under ~120 lines; depth lives in references.

Verification

• DESIGN.md + tokens.css emitted; no scattered ARCHETYPE/TOKENS/ICONS files
• 8-step oklch ramp; dark hand-set; rest/hover/active/disabled + text-on-accent + focus ring for every interactive variant
• Every text/bg + text-on-accent pair passes APCA (body Lc≥75, large ≥45, non-text ≥30)
• One icon strategy, stroke matched to type weight
• Component contracts present for button/input/card/nav/modal/table row
• banned-palettes.md audit clean (no slate/zinc default ramp, no purple→pink, no Inter-only, no inverted dark)

Red Flags

• DESIGN.md generated without reading DIRECTION.md first
• Multiple competing token sources instead of one canonical file
• Interactive states missing hover/active/disabled variants
• Icons or fonts shipped without license or attribution check

Reference Files

• references/design-md-template.md — canonical DESIGN.md structure (copy verbatim)
• references/state-tokens.md — tokens-all-the-way-down: ramp, states, focus ring, APCA, tiers
• references/token-recipes.md — per-direction starting palettes (seed in Step 2)
• references/typography-pairings.md — vetted display/body pairings (paid + free)
• references/banned-palettes.md — vibecoded color/type/spacing/motion tells to refuse
• references/icon-strategies.md — the 5 strategies + per-direction defaults
• references/svg-craft.md — drawing rules for custom SVG sets (grid, stroke, optical sizing)

File Output

Append to docs/skill-outputs/SKILL-OUTPUTS.md:

| YYYY-MM-DD HH:MM | design-system | DESIGN.md + src/styles/tokens.css | [direction] tokens + icon strategy |

Prune Log

Last pruned: 2026-07-04

• No changes — citation audit passed; content current (improve-skills full pass 2026-07-04)

Impact Report

Design system built: [feature]
Direction: [name]
Token format: [shadcn HSL / oklch / @theme]
Color slots (with states): [count] | Neutral ramp: 8-step
APCA: [all pass / fixes applied]
Icon strategy: [name] | Component contracts: [count]
Files: DESIGN.md, src/styles/tokens.css[, tokens.ts]
Handoff to: frontend-design (build)