generated: '2026-08-13'
method: searched
source: https://github.com/b12io/metronome + https://www.npmjs.com/package/@b12/metronome
note: >-
  B12 ships one first-party client-side component library, Metronome, its
  internal design system, published openly on npm under Apache-2.0. It is not an
  API integration surface — it is the UI toolkit B12 builds its own product
  with — but it is a genuine, actively maintained, publicly consumable
  first-party component distribution.

families:
- name: Metronome
  kind: design-system
  official: true
  package: '@b12/metronome'
  registry: npm
  version: 1.1.36
  published: '2026-07-30'
  first_published: '2020-03-23'
  release_count: 50
  license: Apache-2.0
  repository: https://github.com/b12io/metronome
  install: npm install @b12/metronome
  description: >-
    Metronome is the design system B12 uses for developing consistent user
    experiences across its product.
  loader: npm/bundler import
  cdn: null
  note: >-
    Actively maintained — most recent release two weeks before this pass. No
    hosted CDN build or script-tag distribution was found, so the version a
    consumer gets is pinned by their own lockfile.

embedded_surfaces:
- name: WebsiteGeneratorPreviewImage
  kind: mcp-ui-resource
  official: true
  uri: ui://WebsiteGeneratorPreviewImage.html?v=2
  mime_type: text/html;profile=mcp-app
  description: >-
    React application rendered inside an MCP host to display the static preview
    image of a generated website.
  served_from: https://mcp.b12.io/mcp (resources/list)
  ui_domain: 9f33849571a88c7220a5c4aa245f32d1.claudemcpcontent.com
  note: >-
    An MCP-UI embedded component, not an installable one. It is delivered to the
    agent host as part of a tool result and cannot be embedded in a third-party
    page. The preview it renders is static — users cannot edit the site inside
    it.

not_found:
- kind: embeddable-widget
  note: No embeddable B12 site/form widget or JS element library for third-party pages was found.
- kind: embedded-dashboard
  note: No embedded analytics or dashboard component is published.

x-evidence:
  fetched: '2026-08-13'
  probes:
  - {url: 'https://registry.npmjs.org/@b12%2fmetronome', http_status: 200}
  - {url: 'https://api.github.com/orgs/b12io/repos', http_status: 200}
  - {url: 'https://mcp.b12.io/mcp', method: 'POST resources/list', http_status: 200}