UI Toolkit Server

npm version CI Tests Snyk Security Known Vulnerabilities Socket License: MIT

The most comprehensive UI MCP server available. 13 tools, 5 resources, 3 prompts for end-to-end UI development: generate components, manage design tokens, audit accessibility, auto-fix issues, inspect live pages, compare screenshots, generate Storybook stories, extract Figma styles, compose layouts, and preview responsive designs -- across React, Vue, Svelte, Angular, and Web Components.

Works with any MCP-compatible client including Claude Desktop, Claude Code, Cursor IDE, Continue.dev, Cline, and Zed.

Installation

npx (No Install)

npx -y @elsahafy/ui-toolkit-mcp

npm (Global)

npm install -g @elsahafy/ui-toolkit-mcp

Claude Code CLI

claude mcp add ui-toolkit -- npx -y @elsahafy/ui-toolkit-mcp

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "ui-toolkit": {
      "command": "npx",
      "args": ["-y", "@elsahafy/ui-toolkit-mcp"]
    }
  }
}

Cursor IDE

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "ui-toolkit": {
      "command": "npx",
      "args": ["-y", "@elsahafy/ui-toolkit-mcp"]
    }
  }
}

Optional: Browser Tools

For inspect_page, live_audit, and responsive_preview, install Playwright separately:

npm install playwright
npx playwright install chromium

All other tools work without Playwright.

Tools (13)

Component Generation

generate_component

Generate production-ready UI components from natural language. Automatically audits the output and reports issues inline.

"Generate a card component with image, title, and action buttons in React"

Parameters:

• description (required) -- What to build
• framework (required) -- react | vue | svelte | angular | web-components
• component_name (required) -- PascalCase name (e.g., ProductCard)
• variant -- default | outlined | filled | ghost | elevated
• size -- sm | md | lg | xl
• auto_audit -- Automatically audit generated output (default: true)
• include_styles -- Include CSS with design tokens (default: true)
• include_tests -- Generate test file (default: false)
• responsive -- Include breakpoints (default: true)

Generated components are automatically registered in the component registry.

compose_layout

Compose a full page layout from previously generated components in the registry.

"Compose a page from Hero, Features, and Footer components in React"

Parameters:

• component_names (required) -- Array of component names from the registry
• framework (required) -- Target framework
• layout_description -- Description of the page layout

Produces a complete page with imports, semantic structure (<header>, <main>, <footer>), and skip navigation.

Design Tokens

import_design_tokens

Import design tokens from Figma Tokens JSON, Style Dictionary, or CSS custom properties.

Parameters:

• tokens_json (required) -- Raw JSON string of tokens
• format (required) -- figma-tokens | style-dictionary | css-custom-properties
• namespace -- Optional prefix (e.g., brand)
• merge_strategy -- replace | merge-overwrite | merge-keep

extract_figma_styles

Extract design tokens directly from a Figma file via the REST API.

Parameters:

• figma_file_key (required) -- Alphanumeric file key from Figma URL
• figma_pat (required) -- Figma Personal Access Token (never stored or logged)
• node_ids -- Optional specific nodes to extract
• namespace -- Optional CSS variable prefix
• merge_strategy -- How to handle existing tokens

export_tokens

Export the active token store as CSS custom properties, JSON, or Style Dictionary format.

Parameters:

• format -- css | json | style-dictionary (default: css)

clear_tokens

Clear all design tokens from the active store.

Auditing & Fixing

audit_component

Audit markup for WCAG accessibility, performance, and responsive design issues. Returns scored findings with fix suggestions.

Parameters:

• markup (required) -- HTML/JSX/Vue/Svelte markup
• component_name -- For report labeling
• categories -- ["accessibility", "performance", "responsive"]
• wcag_level -- A | AA | AAA
• framework -- Affects how markup is parsed

29 built-in rules: 12 accessibility (WCAG), 9 performance, 8 responsive design.

auto_fix_component

Automatically fix common accessibility and performance issues based on audit findings.

"Auto-fix the accessibility issues in this component"

Parameters:

• markup (required) -- The markup to fix
• findings (required) -- Array of AuditFinding objects from audit_component

Supported auto-fixes: missing alt text, missing lang attribute, missing lazy loading, positive tabindex, px font-sizes to rem.

live_audit

Navigate to a live URL and audit the rendered HTML. Combines browser inspection with markup auditing in one call. Requires Playwright.

Parameters:

• target_url (required) -- HTTP/HTTPS URL (private IPs blocked)
• categories -- Audit categories to run
• wcag_level -- WCAG conformance level

Browser Tools (Playwright)

Install separately: npm install playwright && npx playwright install chromium

inspect_page

Navigate to a live URL and extract accessibility tree, component structure, performance metrics, and screenshot.

Parameters:

• target_url (required) -- HTTP/HTTPS URL (private IPs blocked)
• viewport_width / viewport_height -- Viewport size
• wait_for -- load | domcontentloaded | networkidle
• timeout_ms -- Navigation timeout
• include_screenshot -- Base64 PNG screenshot (default: true)

visual_diff

Pixel-by-pixel PNG comparison for visual regression testing. No Playwright required.

Parameters:

• before_image (required) -- Base64 PNG
• after_image (required) -- Base64 PNG
• threshold -- Per-channel tolerance (0-255, default: 10)

responsive_preview

Screenshot a URL at mobile (375px), tablet (768px), and desktop (1280px) viewports. Requires Playwright.

Parameters:

• target_url (required) -- HTTP/HTTPS URL (private IPs blocked)

Storybook

generate_story

Auto-generate CSF3 Storybook stories with prop detection, play functions, and accessibility addon config.

Parameters:

• component_code (required) -- Full component source code
• framework (required) -- react | vue | svelte | angular
• component_name (required) -- PascalCase name
• story_title -- Storybook path (default: Components/{name})

Detects props via regex from: TypeScript interfaces (React), defineProps (Vue), export let (Svelte), @Input() (Angular).

Resources (5)

URI	Description
ui://tokens/active	Currently loaded design tokens
ui://patterns/components	Component pattern library (12 patterns with a11y requirements)
ui://components/registry	Registry of all generated components with audit scores
ui://server/health	Server version, tool count, token count, uptime
ui://audit/checklist	Full audit rule reference (auto-generated from rule definitions)

Prompts (3)

Prompt	Description
build_page	Generate a full page with multiple components using design tokens
component_audit	Comprehensive audit + fix workflow
design_to_code	Full Figma-to-code: extract tokens, generate components, audit, generate stories

Key Features

Audit-at-Generation-Time

Every component generated by generate_component is automatically audited for accessibility, performance, and responsive issues. Critical findings are reported inline. No other UI MCP server does this.

Component Registry

All generated components are tracked with metadata (framework, tokens used, audit score, timestamp). Use compose_layout to assemble them into full pages.

Design Token Pipeline

Import tokens from Figma, Style Dictionary, or CSS custom properties. Export in any format. Tokens are automatically applied to generated components.

Framework Agnostic

All 13 tools support React, Vue, Svelte, Angular, and Web Components. One server, any framework.

Architecture

src/
  index.ts                          # Server entry (thin orchestrator)
  lib/
    types.ts                        # Shared TypeScript interfaces
    token-store.ts                  # In-memory design token state
    component-registry.ts           # Component tracking
    framework-templates.ts          # 5 framework component generators
    story-templates.ts              # CSF3 story templates + prop detection
    accessibility-rules.ts          # 12 WCAG audit rules
    performance-rules.ts            # 9 performance audit rules
    responsive-rules.ts             # 8 responsive design rules
    pattern-library.ts              # 12 component patterns
    browser.ts                      # Playwright lifecycle + URL validation
    validation.ts                   # Shared input validation
    utils.ts                        # Shared utilities (kebab, clamp, fileExt)
  tools/
    generate-component.ts           # + auto-audit + registry
    import-design-tokens.ts
    audit-component.ts
    auto-fix-component.ts
    inspect-page.ts
    visual-diff.ts
    generate-story.ts
    extract-figma-styles.ts
    export-tokens.ts
    clear-tokens.ts
    live-audit.ts
    responsive-preview.ts
    compose-layout.ts
    index.ts                        # Tool registry + dispatch
  resources/
    index.ts                        # 5 resources
  prompts/
    index.ts                        # 3 workflow prompts
tests/
  lib/                              # 11 library test files
  tools/                            # 12 tool test files

184 tests across 23 test files. All source files have dedicated test coverage.

Security

• No code execution -- all markup parameters are analyzed via regex, never evaluated
• URL validation blocks private IPs (127.x, 10.x, 172.16-31.x, 192.168.x, fe80::, fc00::, localhost)
• Only HTTP/HTTPS schemes allowed for browser tools
• Figma PAT is never stored, logged, or returned in responses (sanitized from error messages)
• All string inputs have maxLength constraints enforced at runtime
• No credential keywords in resource URIs
• Input validation helper shared across all tool handlers

License

MIT