components-build-mcp by getlokiui - MCP Server

components-build-mcp

An MCP (Model Context Protocol) server that implements the components.build specification for grading, generating, and validating UI components.

About

This MCP server provides AI assistants with tools to:

Access the complete components.build specification - The full documentation embedded and searchable
Grade components - Validate any component against the spec's rules
Generate compliant components - Create new components that follow all best practices
Search documentation - Find specific patterns, rules, or concepts

The components.build specification is an open-source standard for building modern, composable, and accessible UI components, co-authored by Hayden Bleasel and shadcn.

Framework Support

Feature	Frameworks Supported
Specification	Framework-agnostic
Grading	Framework-agnostic (React, Vue, Svelte, Angular, etc.)
Templates	React + TypeScript

The grading rules check for universal patterns (accessibility, composition, data attributes) that apply to any framework.

Installation

For Claude Code / Claude Desktop

npm install -g components-build-mcp

Add to your Claude configuration (~/.claude/claude_desktop_config.json):

{
  "mcpServers": {
    "components-build": {
      "command": "components-build-mcp"
    }
  }
}

For Local Development

git clone https://github.com/getlokiui/components-build-mcp.git
cd components-build-mcp
npm install
npm run build

Add to Claude config with full path:

{
  "mcpServers": {
    "components-build": {
      "command": "node",
      "args": ["/path/to/components-build-mcp/dist/index.js"]
    }
  }
}

Available Tools

Documentation Tools

Tool	Description
`get_specification`	Get the full spec or a specific section
`search_specification`	Search for terms like "aria", "CVA", "data-slot"
`list_specification_sections`	List all 16 documentation sections

Grading & Validation Tools

Tool	Description
`grade_component`	Grade code and get detailed feedback with score
`check_compliance`	Quick pass/fail check (threshold: 80/100)
`get_rules`	Get grading rules by category
`get_rule`	Get details about a specific rule
`list_rules`	List all rules with severity and weight

Generation Tools

Tool	Description
`generate_component`	Generate a compliant component from templates
`get_template`	Get reference templates (button, card, input, etc.)
`get_quick_reference`	Get the cheat sheet

Usage Examples

Once configured, ask your AI assistant:

"Show me the components.build spec section on accessibility"

"Grade this component against the spec:
export const Button = ({ children }) => <button>{children}</button>"

"Generate a Card component with composable sub-components"

"Search the spec for keyboard navigation patterns"

"What rules does the grader check for?"

Specification Sections

The complete components.build specification includes:

Section	Description
`overview`	Introduction and purpose
`definitions`	Terminology (Primitive, Component, Block, etc.)
`principles`	Core principles (Composability, Accessibility, etc.)
`composition`	Root/Trigger/Content pattern
`accessibility`	Complete a11y guide
`designTokens`	CSS variables and theming
`state`	Controlled/uncontrolled state
`styling`	cn(), CVA, tailwind-merge
`types`	TypeScript patterns
`polymorphism`	The "as" prop
`asChild`	Radix Slot pattern
`dataAttributes`	data-state/data-slot patterns
`docs`	Documentation standards
`registry`	shadcn CLI distribution
`marketplaces`	Component marketplaces
`npm`	NPM distribution

Grading Rules

Components are graded on:

Types - Extending HTML props, exporting types, spreading props correctly
Styling - Using cn() utility, class order, design tokens
Accessibility - ARIA attributes, keyboard navigation, semantic HTML
Composition - Single element wrapping, composable patterns
State - Supporting controlled and uncontrolled usage
Naming - Following conventions (Root, Trigger, Content, etc.)

HTTP API

A Vercel-compatible HTTP API is also available for non-MCP usage:

# Deploy to Vercel
cd components-build-mcp
vercel --prod

Endpoints:

GET /?action=rules - Get all rules
POST /?action=grade - Grade component code
POST /?action=generate - Generate component
GET /?action=quick-reference - Get cheat sheet

Credits

This project implements the components.build specification.

The specification is:

Co-authored by Hayden Bleasel and shadcn
Licensed under Apache License 2.0

This MCP server is a community project by Audrey Klammer and is not officially affiliated with or endorsed by Vercel, Inc.

License

Apache License 2.0 - See for details.

Contributing

Contributions are welcome! Please read the components.build specification first to understand the patterns and rules.

getlokiui/components-build-mcp