Standards

A brand’s rules are its source. Everything else is drawn from them, in formats other tools already read, so nobody has to copy a hex code by hand:

Format	For	Where
AdCP brand.json	Ad tech and agents that look a brand up by its domain	BrandHub, `/{org}/{brand}/brand.json`; a verified domain’s `/.well-known/brand.json`. Read too, to start a brand
W3C design tokens (DTCG)	Style Dictionary, Tokens Studio, Figma importers	`?format=json`
Stylesheets and themes	CSS, Sass, Less, Tailwind, TypeScript, shadcn/ui, Material UI, Chakra UI	`?format=css`, and the others
DESIGN.md	Coding agents	`?format=designmd`
llms.txt	Any agent that reads the web	BrandHub, `/{org}/{brand}/llms.txt` and `/llms.txt`
rules.json	Anything that wants every rule, losslessly	BrandHub, `/{org}/{brand}/rules.json`
MCP	Agents that ask questions, in chat apps and editors	`/api/v1/mcp`
The brand folder	Git, review, scripts	The sync API and the CLI

Where tokens come from

The same formats come from two places:

	Reads	Who
`GET /api/v1/brand/tokens?format=css&brand=acme`	The brand as it stands now, draft included	Anyone who can read the workspace, with a key or signed in
`https://{hub}/{org}/{brand}/tokens?format=css`	The latest release, or `@{n}` for one: `/{org}/{brand}@4/tokens`	Anyone, for a public brand on BrandHub

Both take context: ?context=dark-background gives each rule’s version for that context and the default of the rest. Without it, every rule’s default. In the app, the brand’s Tokens and rules tab shows every format, and Use this brand copies their addresses. On BrandHub, file URLs inside an answer (font files, logos) are signed for a day, and the answer itself may be cached for an hour: fetch it again rather than keeping its URLs.

W3C design tokens

format=json is the Design Tokens Format (DTCG 2025.10). Each rule’s dotted key is its path: color.primary is { "color": { "primary": { ... } } }.

Rule	Token
color	`$type: color`, `$value` in sRGB: `components` from 0 to 1, `alpha` when below 1, and `hex`
color with `spec.gradient`	The color as above, and `{key}Gradient` beside it: `$type: gradient`, stops by reference (`{color.primary}`) or by value, positions from 0 to 1; kind, angle and the CSS in `$extensions["com.artbucket"]`
number	`$type: number`
type scale (a list of numbers)	Steps `1`, `2`, … each `$type: dimension` in px
font	A group: `fontFamily`, `fontSize` (px) and `fontWeight` when set; the files in `$extensions["com.artbucket"].files`, each with its URL, weight, style and media type
a rule carrying a font’s file	`fontFamily` (and `fontWeight`) as references to that font: a heading style set in the brand’s face
text, and lists that aren’t a scale	Left out: they are guidance, not values

A rule’s usage becomes its $description.

{
  "color": {
    "primary": {
      "$type": "color",
      "$value": { "colorSpace": "srgb", "components": [0.1216, 0.4353, 0.9216], "hex": "#1f6feb" },
      "$description": "Buttons, links and the mark's tile."
    }
  },
  "type": {
    "heading": {
      "fontFamily": { "$type": "fontFamily", "$value": "Inter" },
      "fontSize": { "$type": "dimension", "$value": { "value": 40, "unit": "px" } },
      "fontWeight": { "$type": "fontWeight", "$value": 700 },
      "$extensions": {
        "com.artbucket": {
          "files": [{ "url": "https://app.example.com/a/6f1c...", "weight": 700, "style": "normal", "mime": "font/woff2" }]
        }
      }
    }
  }
}

A key that is both a token and the start of another key (color.primary and color.primary.dark) nests the second inside the first, which DTCG readers refuse: name one of them otherwise (color.primaryDark).

Token formats

`format`	File
`css`	`{brand}.tokens.css`	Custom properties on `:root`, with `@font-face` for every font file
`scss`	`_{brand}-tokens.scss`	Sass variables and `@font-face`
`less`	`{brand}.tokens.less`	Less variables and `@font-face`
`tailwind`	`{brand}.theme.css`	A Tailwind CSS 4 `@theme`: utilities like `bg-primary` and `font-headings`
`tailwind3`	`tailwind.{brand}.js`	`theme.extend` for a Tailwind CSS 3 config
`ts`	`{brand}.tokens.ts`	One typed object, for styled-components, Emotion, vanilla-extract, React Native
`shadcn`	`{brand}.shadcn.css`	Colors named like shadcn/ui’s take their place, with readable foregrounds
`mui`	`{brand}.mui-theme.ts`	A Material UI `createTheme` with the palette and typography
`chakra`	`{brand}.chakra-system.ts`	A Chakra UI 3 system over the defaults
`json`	`{brand}.tokens.json`	W3C design tokens
`designmd`	`DESIGN.md`	DESIGN.md

Names follow keys: logo.minClearSpace is --logo-min-clear-space in CSS. Colors, numbers, fonts (family, size, weight and their files) and type scales become tokens; a font’s files are loaded from Artbucket by @font-face, with each file’s weight and style read from its name (Inter-BoldItalic.woff2). A number is written as it is, without its spec.unit.

:root {
  /* Buttons, links and the mark's tile. */
  --color-primary: #1f6feb;
  --type-heading-font-family: "Inter";
  --type-heading-font-size: 40px;
  --type-heading-font-weight: 700;
  --type-scale-1: 12px;
  --logo-min-size: 24;
}

DESIGN.md

format=designmd is a DESIGN.md (Google Labs, version alpha), to keep at a repository’s root for coding agents. It is the one format that carries guidance as well as values:

Front matter: colors by their local name (color.primary is primary; when no color is named primary, primary refers to the first), typography per face (family, size, weight), rounded for number rules named like a radius (in px), and spacing for ones named like a gap, margin or padding.
Prose: Overview (text and lists of any other group), Colors, Typography, Layout, Shapes, and Do’s and Don’ts, from lists whose key reads as a do or a don’t.

llms.txt

Every public brand on BrandHub has /{org}/{brand}/llms.txt: the brand in words for an agent, with who listed it and whether that is verified, links to its other files, its portal’s terms, and every rule by context, each with its files. BrandHub’s own /llms.txt says how an agent finds a brand there, and lists them. A domain’s own /llms.txt is the first place the public Brand Agent Score looks: link your brand.json, your tokens and your MCP server from it.

rules.json

/{org}/{brand}/rules.json is the listing as data, lossless: the release, who listed it, its versions, its portal and terms, and every rule with its key, label, context, type, value, spec, usage and files, signed for a day.

{
  "data": {
    "org": "acme",
    "brand": "acme",
    "name": "Acme",
    "version": 4,
    "url": "https://hub.example.com/acme/acme",
    "rules": [
      { "key": "color.primary", "label": "Acme blue", "context": null, "type": "color", "value": "#1f6feb", "spec": { "pair": "color.background" }, "usage": "Buttons, links and the mark's tile.", "assets": [] }
    ]
  }
}

MCP

/api/v1/mcp serves the same brand to agents that connect: brand_rules for a context, get_theme, list_pages and get_page, and the rules and pages as resources (artbucket://brands/{slug}/rules/{context}). See MCP.

How BrandHub files are served

Public brands only, from the latest release, or the one @{n} names.
Keyless, with Access-Control-Allow-Origin: *, cached up to an hour.
A community listing (its organization proved neither a domain nor a GitHub account) answers with X-Robots-Tag: noindex.
Each read but the badge’s is a pull, counted in Insights.

General

Installation

Configuration

Guides

Brand as code

Developers

Decisions

Where tokens come from

W3C design tokens

Token formats

DESIGN.md

llms.txt

rules.json

MCP

How BrandHub files are served

​Where tokens come from

​W3C design tokens

​Token formats

​DESIGN.md

​llms.txt

​rules.json

​MCP

​How BrandHub files are served

Where tokens come from

W3C design tokens

Token formats

DESIGN.md

llms.txt

rules.json

MCP

How BrandHub files are served