Design System Structure Agent Skill

Structures a Flutter design system as tokens→theme→modifiers→shapes with two-tier tokens (primitives named by measured value, semantic…

Context cost
10.3k tokensestimated from the bundle, loaded when it triggers
Bundle
7 of 9 fileshanded out here; the rest is at its source
Licence
MITthe author’s own terms
Last change
—no release on file
Servers it uses
Noneruns standalone

What it does

Structures a Flutter design system as tokens→theme→modifiers→shapes with two-tier tokens (primitives named by measured value, semantic slots named by role) exposed through a ThemeExtension read via an asserting of(context); hand-authors both light and dark ColorScheme instead of ColorScheme.fromSeed, keeps every raw color/hex/Colors./Curves./Duration/BorderRadius/fontSize inside lib/theme/ behind a no-raw-values gate, collapses animation to zero under reduced motion, restores the persisted theme before first paint, bundles fonts (never google_fonts/dynamic_color), and derives each stateful…

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

fluttermobile

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md18.8 kB · preview
--- name: design-system-structure ---
6# design-system-structure
7
8A design system is code that is *incapable of holding a stray opinion*: every aesthetic value lives in one directory, and every widget reads it back through a named slot. This skill owns how tokens, themes, components, and shapes are **structured and consumed** — not which colors or radii to pick (that belongs to your design source of truth). Getting the structure right makes a reskin a diff lib/theme/ and turns a stray Color(0xFF…) in feature code into a build failure instead of a style nit.
9
10Read the reference for the task at hand:
11- references/token-tiers-and-themeextension.md — two-tier token naming, ThemeExtension mechanics, the asserting of(), hand-authored ColorScheme vs fromSeed, honest lerp.
12- references/motion-and-reduced-motion.md — the three animations Material mounts by default, why NoSplash is not enough, reduced-motion-means-zero, pumpAndSettle bans in tests.
13- references/typography-and-fonts.md — bundling fonts, LicenseRegistry, FontWeight drives wght, silent FontVariation no-ops, subsetting without instancing, per-script fallback cascades.
14- references/contrast-and-redundant-encoding.md — AA as a unit test, ≥3 grayscale-legible signals per meaning, reading a11y flags from MediaQuery.
15
16Run scripts/check_raw_values.sh and scripts/check_font_bundling.sh before a PR.
17
18## Non-negotiable rules
19
201. **No raw aesthetic value outside lib/theme/** — the gate is the law.** A Color(0x…) / Colors.* (except transparent) / Curves.* / Duration(milliseconds:|seconds: (except Duration.zero) / literal BorderRadius.circular(n) / fontSize: n in feature or shared UI code fails scripts/check_raw_values.sh. A legitimate new need is a **new token slot, never a // ignore** — one place to diff is the whole point.
212. **Two token tiers; widgets read only the semantic tier.** Tier 1 = primitives named by the **measured value** (neutral12 = OKLCH lightness ×100), never by rank (grey700), appearance (darkGrey), or brand (brandPrimary). Tier 2 = semantic slots named by role (surface, onSurface, hairline, accent). A widget that reaches a Tier-1 primitive has hardcoded one theme. WHY: rank scales have no room to insert and lie in dark mode; appearance names invert catastrophically; brand names die with the brand.
223. **Read tokens through a ThemeExtension and an asserting of(context).** Never a static const class, never an InheritedWidget side channel. of() asserts on a missing extension — it does **not** ?? fallback. WHY: MaterialApp drives light/dark switching and correct-by-construction invalidation; a fallback silently ships a theme no test verified, and loud-in-debug beats wrong-in-field.
234. **Hand-author ColorScheme; never ColorScheme.fromSeed (or dynamic_color) for identity.** fromSeed's per-role overrides do **not** propagate — override surface and surfaceContainerHigh stays seed-derived. State every role you consume, keep the M3 role names so Material widgets theme themselves, and let unstated roles take ColorScheme's own defaults, not a seed's opinion. WHY: "seed plus a few overrides" means owning the ~9 roles you chose *and* every seam of the ~40 you didn't.
245. **Layer the system: tokens → theme → modifiers/components → shapes.** Author light **and** dark by hand (dark is never an auto-flip), each passing AA independently, and attach every extension to **both** ThemeDatas. Inject the theme exactly once, at the composition root. WHY: theming the app must touch one directory; a palette-only dark theme ships light's ratios into the dark.
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md2,448 words
Files7
LicenceMIT
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈260
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
10,090
on trigger
The instruction body and 6 supporting files, read only when the skill fires.
5.2%
of a 200k window
Ten skills this size would take about 52% of the window before you open a file.
050k100k150k200k context window

10.3k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

Its SKILL.md does not declare which tools it asks the agent for, so what it touches is whatever the instructions themselves ask for — read them before you install it.

What it asks for
Writes filesnot declared
Network accessnot declared

This SKILL.md carries no allowed-tools line, so neither is declared. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

The download carries 7 of the 9 files in its source folder; the list here names 7 files, 44.4 kB on disk. Mostly text — the instructions the model reads — with 2 scripts in it that your client would run only if the instructions tell it to. The other 2 are not in the download, nor is 1 file of a type a skill download does not carry — listed after these, with why.

  • SKILL.md18.8 kB
  • references/contrast-and-redundant-encoding.md4.6 kB
  • references/motion-and-reduced-motion.md4.7 kB
  • references/token-tiers-and-themeextension.md6.7 kB
  • references/typography-and-fonts.md6.6 kB
  • scripts/check_font_bundling.sh1.1 kB
  • scripts/check_raw_values.sh1.9 kB

Not in the download

Not carried is a type a skill download does not hold. Marked read: its SKILL.md or scripts name the file, so without it the skill works only in part. Take them from its source.

  • examples/app_theme.dartread · not carried
  • examples/status_encoding.dartread · not carried
  • examples/reduced_motion.dartnot carried
What is not in it

A skill installs nothing and depends on nothing: it is a folder your client reads. This one carries 2 scripts beside the text, so the download is 7 files — not the whole of its source: 3 files are left out, and the skill reads 2 of them. They are listed under the files, with why. The MIT licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Design System Structure · 10.3k tokens when loaded · macOS, Linux mkdir -p .claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/design-system-structure/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/design-system-structure" ] && { [ ! -e .claude/skills/design-system-structure ] || { mv .claude/skills/design-system-structure "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/design-system-structure" .claude/skills/ && echo "Installed .claude/skills/design-system-structure"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add zakariaf/design-system-structure

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/design-system-structure/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/design-system-structure/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/design-system-structure" ] && { [ ! -e ~/.claude/skills/design-system-structure ] || { mv ~/.claude/skills/design-system-structure "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/design-system-structure" ~/.claude/skills/ && echo "Installed ~/.claude/skills/design-system-structure" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/design-system-structure/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where. Not in this download: 3 files of its source, 2 of them read by its SKILL.md or scripts (the full list, and why). Take them from its source.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/
Claude DesktopCustomize › Skills
ChatGPTSkills › Create › Upload
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok Build.grok/skills/
Microsoft CopilotSkills › Upload a skill
PerplexityComputer › Skills › Upload a skill
DeepSeek Harness.dsh/skills/
Zed.agents/skills/
Devin Desktop.devin/skills/
Windsurf (legacy).windsurf/skills/
OpenAI Agents SDKInstructions or sandbox Skills
HTTP / APIa request parameter
This release
Versionnot versioned
Publishedno release date on file
PriceFree
Referencezakariaf/design-system-structure

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

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