Arc for AI agents

Connect the MCP server

A remote, read only server. The first time you connect, your AI tool opens Arc's sign-in: a free account is enough, and Pro source unlocks with your plan. No key to copy.

claude mcp add --transport http arc https://uiarc.dev/api/mcp

search_components

Find components and blocks by intent, such as “confirm a destructive action”.

list_components

Browse by category, tag, tier, or kind.

get_component

When to use it and when not to, usage, props, accessibility, motion, responsive, and performance notes, and the install command. With a Pro token, Pro items include their source files.

get_install_command

One shadcn command for several items, with setup notes. With a Pro token, it covers Pro items too.

get_skill

One Arc skill file: the entry point, design, copy, components, composition, motion, accessibility, responsive, the review checklist, or a worked example.

Add the agent skill

Teaches the agent when to reach for Arc, how to install it, and the design rules to keep.

npx shadcn@latest add https://uiarc.dev/r/arc-skill.json

Other agents can read SKILL.md directly, or paste INSTRUCTIONS.md into AGENTS.md, CLAUDE.md, or Cursor rules.

• SKILL.mdEntry point: workflow, principles, never-do list, and quick decisions
• INSTRUCTIONS.mdShort always-on rules for AGENTS.md, CLAUDE.md, or Cursor rules
• checklist.mdThe review loop to run before finishing, with grep sweeps
• components.mdChoosing the right component or block by job, with ids
• composition.mdPage containers, dashboards, marketing sections, states, React correctness
• copy.mdSentence case, no eyebrows or em dashes, verbs on buttons, honest claims
• design.mdColor, type, surfaces, concentric radii, spacing, and icons
• motion.mdMotion tokens, spring choice, patterns with code, reduced motion
• accessibility.mdFocus without rings, semantics, keyboard, and announcements
• responsive.mdWidths to check, overflow, tables, and touch targets
• example-settings.mdA worked account settings page
• example-pricing.mdA worked pricing section with plans, comparison, and FAQ
• example-dashboard.mdA worked analytics overview with KPIs, chart, and table

Pro skills

Longer playbooks for whole pages and reviews. Pro members download them signed in from /api/skills, or read them through the MCP server signed in with a Pro account (or a Pro token).

• Arc Pro skillProEntry point: picks the right Pro workflow and sets up Pro access
• Full-page generationProBrief, plan region by region with every state, build, and verify a whole page, or stop at the plan
• Design system generationProA brand theme on Arc tokens with contrast checked in both themes
• Refactor to ArcProMigrate custom, shadcn/ui, MUI, or Chakra UI to Arc with parity checks
• Motion auditProInventory every animation, assign tokens, cut motion that explains nothing
• Responsive auditProMeasure five widths, fix overflow, layout, and touch, then re-measure
• Accessibility auditProA ranked audit of structure, keyboard, contrast, and motion with patches

Included with Arc Pro. Signed in, /api/skills returns every Pro skill and /api/skills?id=full-page-generation returns one as markdown.

Install with the shadcn CLI

Every free item is a registry item. Shared tokens and Arc dependencies come along automatically.

npx shadcn@latest add https://uiarc.dev/r/button.json

{  "registries": {    "@uiarc": "https://uiarc.dev/r/{name}.json"  }}

npx shadcn@latest add @uiarc/button @uiarc/dialog @uiarc/signup-form

Import @/components/arc/foundation.css once in your root layout. Items install into an arc/ folder under the components alias in components.json and import each other with relative paths, so src/ projects and monorepo packages work as they are.

Pro access

Signed in through your AI tool, the MCP server unlocks Pro for your account automatically. Personal access tokens are for the shadcn CLI and for clients without MCP sign-in.

1. Create a token

   Open Pro access in your account, name the token after the tool or machine, and copy it. It is shown once.

2. Or connect the MCP server with the token

   get_component then returns the full source of Pro items, get_install_command returns @uiarc-pro commands, and get_skill returns Pro skills.

   Claude CodeCursorVS CodeCodex

   Terminal

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   claude mcp add --transport http --scope user arc https://uiarc.dev/api/mcp \  --header "Authorization: Bearer arc_pro_..."

   Paste your token in place of arc_pro_... The user scope keeps it out of project files.

3. Install Pro items with the shadcn CLI

   239 Pro components, blocks, and templates install from the @uiarc-pro registry. Pieces that ship photos are copied from their docs page instead.

   components.json

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   {  "registries": {    "@uiarc": "https://uiarc.dev/r/{name}.json",    "@uiarc-pro": {      "url": "https://uiarc.dev/r/pro/{name}.json",      "headers": {        "Authorization": "Bearer ${ARC_PRO_TOKEN}"      }    }  }}

   .env.local

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   ARC_PRO_TOKEN=arc_pro_...

   Then install by name

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   npx shadcn@latest add @uiarc-pro/dock @uiarc-pro/arc-crm

The shadcn CLI expands ${ARC_PRO_TOKEN} from your environment or .env.local; never commit the token. Each account can hold 10 active tokens, each allows 120 requests a minute, and a token stops working when you revoke it or Pro ends. Free dependencies come from the public registry and Pro dependencies through @uiarc-pro, so keep both entries.

Readable context

Plain text and JSON for agents, search, and your own tooling.

• llms.txtIndex of every component and block with links to its markdown
• llms-small.txtOverview, install, and one line per item, for small context windows
• llms-full.txtThe whole library as one markdown file for a single context load
• Component markdownAny component or block as markdown: add /markdown to its page URL
• Registry indexshadcn registry with 143 installable items
• CatalogMetadata for every item, including Pro: use cases, keywords, and notes, without source
• Skill indexEvery skill file as JSON

Try a prompt

Name the job, not the markup. The agent searches Arc before it writes anything.

Build a settings page with Arc. Use the Arc MCP server to findcomponents for the profile form, notification switches, and adestructive delete action. Install them with the shadcn CLI andcheck the page in light and dark themes.