Arc for AI agents

Connect the MCP server

A remote, read only server. No account or key.

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 with a Pro token.

• Arc Pro skillProEntry point: picks the right Pro workflow and sets up Pro access
• Full-page generationProBrief, plan, build, and verify a whole page against the checklist
• Page compositionProPlan a page region by region with the right blocks and every state
• 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=page-composition 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 @/registry/foundation.css once in your root layout. Arc files use the @/* alias for the project root.

Pro access

Pro members connect AI tools and the CLI with a personal access token. Without one, everything above keeps working, free and anonymous.

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. 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

   CopyCopiedFailed

   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

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

   components.json

   CopyCopiedFailed

   {  "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

   CopyCopiedFailed

   ARC_PRO_TOKEN=arc_pro_...

   Then install by name

   CopyCopiedFailed

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

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 119 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.