What is a skill?

Tell your agent "this dropdown feels slow" and, with the design-engineering skill installed, it does not guess. It opens a note about easing curves, reads that a menu should take about 200ms with a strong ease-out, and fixes it to that. Try a few requests and watch where each one lands:

A folder of notes

A skill is a folder of plain text files written for an agent. At the top sits one file, SKILL.md, with a short description of when the skill applies. Beside it are the notes themselves.

That is all it is. No code to run, no magic. Just instructions, written down once, so the agent does the work the way an expert would instead of the way the average of the internet would.

design-engineering/
  SKILL.md              ← "load me when reviewing UI, picking easing…"
  references/
    motion/easing-curves.md
    motion/duration-table.md
    surface/contrast-and-color-scheme.md
    … about 200 more

How the agent knows when to load it

Your agent reads only the short description of every installed skill at first. When your request matches one ("review this card", "why does this feel off"), it opens that skill's SKILL.md. From there it follows links to the one or two notes the job needs, and ignores the rest.

This matters because an agent can only hold so much in mind at once. Loading two notes about motion beats loading two hundred notes about everything.

One skill, one door

design-engineering is a single skill with a single entry point. Whatever you want, you start the same way:

$ /design-engineering [verb] [target]

The slash command /design-engineering opens the skill. What you type after it decides where it goes:

1. A verb

   If the first word is a verb like review, polish, motion or tells, the agent opens that command and follows it step by step. /design-engineering review src/PricingCard.tsx reviews that file.

2. A plain request

   If you just describe the problem, a router note reads it, decides which part of the craft owns it, and hands off. /design-engineering why does this card feel flat.

3. Nothing at all

   On its own, /design-engineering shows a menu of verbs, leading with the two or three that fit what you are doing. It never runs one without asking.

Thirteen clusters, two hundred notes

Behind the door, the notes are grouped into 13 clusters, one per part of the craft: philosophy, motion, surface (color and depth), typography, layout, components, anti-patterns (the tells of AI-made UI), faux UI, SVG, sound, launch video, diagrams, and meta (how to review and direct).

Each note is a node: one idea, a few hundred words, with exact values and links to related nodes. "Never scale from zero" is a node. "The duration table" is a node. The modules of this course follow the same clusters, so what you learn here is exactly what your agent reads.

Your own taste, on top

Two files in the skill are meant for you to edit: pov.md, where you write opinions that override the skill's defaults, and gotchas.md, where you jot down mistakes the agent made so it never makes them again. You will not need them on day one. Just know the skill is a starting point you can make your own.

/design-engineering which: I want the settings page to feel less cramped. Tell me which cluster and which node own this, and why, before you change anything.