Open Components

Measured conclusion: Alive, not deep-tested. L2 outcome: not_attempted.

Guidelines for UI components with a perfect UX, DX and AX, whether humans or AI agents write them.

Add to your agent

Copy this into your MCP client config:

{
  "mcpServers": {
    "Open Components": {
      "url": "https://mcp.opencomponents.dev/mcp",
      "transport": "streamable-http"
    }
  }
}

Measured tools (6)

• get-contract read-only

  Returns the contract of a component or a foundation, as YAML: its API (props, slots and events), its DOM contract (element, role, states, keyboard and parts), its tokens, and every rule in its checklist, each with a stable ID (like button/keep-focus), a level (must or should), a scope (component, usage or both) and how to check it. It holds every requirement in a fraction of the page's length, and it's the same file as https://opencomponents.dev/raw/docs/<path>.yaml. WHEN TO USE: first, before you build, review or explain a component or its tokens. WHEN NOT TO USE: for some of the rules only (by scope, layer, level or check), use list-rules. For the reasoning or the examples behind a rule, use get-page with its sections.

  Parameters:

  • component (required) — string — The component or foundation, like button or design-tokens.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• get-page read-only

  Reads a docs page as markdown, whole or just the sections you name. Component pages explain why each rule exists, with examples in React, Vue, Svelte, Angular, Solid, Astro and Vanilla: pass a framework to keep only its examples. WHEN TO USE: for the reasoning, an example or the details behind a rule (like the sections ["Loading"] of the button's page), or for a page without a contract, like the introduction or the roadmap. WHEN NOT TO USE: for the requirements alone, use get-contract or list-rules, which are much shorter. To find which page or section covers a topic, use search-docs. A page longer than about 8,000 tokens, like the button's, returns its outline instead: every heading with its anchor and length, so you can ask for the sections you need. So do sections that are too long to return together.

  Parameters:

  • path (required) — string — The page: its name (introduction, roadmap, mcp-server, agent-plugin, design-tokens, button, card, checkbox-group, checkbox, dialog, input, radio-group, spinner, switch, textarea, tooltip), or its path, like /docs/components/button. A URL's #anchor, like the ones search-docs returns, reads that section.
  • sections — array — The sections to read, by heading or anchor, like ["Loading"] or ["#ux-rules"]. Each comes with its sub-sections. Name a parent to tell apart headings that repeat, as in "Every state > Loading".
  • framework — string — Your framework, to keep only its examples.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• get-reference-implementation read-only

  Returns a shipped component's reference implementation: a Vue 3 component that meets every rule in its checklist, the tests that prove it, the helpers it shares with other components and its theme tokens. The live examples on the site run on this code. WHEN TO USE: to build a component that meets the standard, in Vue or by porting it and its tests to another framework, or to see how a rule is met in code. WHEN NOT TO USE: for the requirements, use get-contract. For how the component is used in another framework, use get-page with that framework.

  Parameters:

  • component (required) — string — A component with a reference implementation, like button.
  • files — array — Only these files, like ["Button.vue"] or ["Button.test.ts"]. Leave it out for every file.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• list-components read-only

  Lists what the Open Components standard covers: the components that have shipped (like Button), the foundations every component follows (like Design Tokens), and the components planned on the Roadmap. WHEN TO USE: to check whether a component has a standard yet, to get the name the other tools take for it, or to see what's planned. WHEN NOT TO USE: if you already know the component, call get-contract directly. To find a topic in the docs, use search-docs. Shipped entries come with their page, their contract and how many rules they have. Planned ones have no page, contract or rules yet: hold them to the three layers and Design Tokens, following the Button's structure, as the build-component prompt does.

  Parameters:

  • status — string — Which components to list.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• list-rules read-only

  Lists checklist rules as records, filtered by component, ID, scope, layer, level or check. Each rule has a stable ID to cite in reviews and commits, its level (must or should), its scope, its requirement, how to check it (like a unit test, a review or axe's button-name rule) and a link to it. WHEN TO USE: to review code rule by rule, to get only the rules that apply to a task, to look rules up by ID, or to find the ones a tool can check. Pass scope ["component", "both"] to build or review a component, and ["usage", "both"] to review a screen that uses it. WHEN NOT TO USE: for a component's API, DOM contract and tokens, use get-contract, which has every rule too. It returns up to 50 rules at a time, and total counts every rule that matches. When there are more, pass nextOffset as offset, with the same filters, to get the next page. A component meets the standard when it meets every must rule. Each should rule is expected unless there's a good reason not to follow it.

  Parameters:

  • ids — array — The IDs of the rules to look up, like ["button/keep-focus"].
  • check — array — How the rule is checked.
  • layer — array — ui (how it looks), ux (user experience), dx (developer experience) or ax (agentic experience).
  • level — array
  • limit — integer — How many rules to return, at most.
  • scope — array — Who meets the rule: component (the component itself), usage (the code that uses it) or both. Rules without a scope, like the Design Tokens', match any scope.
  • offset — integer — Where the page starts: 0, or the nextOffset of the page before.
  • automated — boolean — true for the rules tools check all of (unit tests, axe, a type check, a linter or a visual regression test), false for the ones a person checks, at least in part.
  • component — string — The component or foundation, like button or design-tokens.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• search-docs read-only

  Searches the whole standard, every section of every page and every checklist rule, and returns the best matches: where each one is, a short excerpt, and for rules, their ID, level and scope. WHEN TO USE: to find where a topic is covered when you don't know the page or the section, like "focus after delete", "spinner", "aria-pressed" or "dark mode". Then read a section with get-page, or rules with list-rules. WHEN NOT TO USE: to list a component's rules, use list-rules. To see which components there are, use list-components. Search for a few specific words rather than a whole question.

  Parameters:

  • query (required) — string — A few words, like "focus after delete" or "aria-pressed".
  • type — string — Only search sections, or only rules.
  • limit — integer — How many results to return, at most.
  • component — string — Only search this page and its rules, like button or design-tokens.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

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