21st.dev Magic AI Agent

Magic MCP → 21st MCP

Magic MCP is now the 21st MCP. The Magic MCP server (@21st-dev/magic) has been replaced by the unified 21st MCP, installed via the 21st CLI — setup at 21st.dev/mcp. This package remains published as a thin compatibility proxy so old configs keep working.

Install the 21st MCP (recommended)

npx @21st-dev/cli@latest init --client cursor   # or: claude | vscode | windsurf | codex

Or add it manually — it is a plain HTTP MCP server:

{
  "mcpServers": {
    "21st": {
      "url": "https://21st.dev/api/mcp",
      "headers": { "x-api-key": "YOUR_21ST_API_KEY" }
    }
  }
}

Get an API key at 21st.dev/mcp.

Old Magic API keys were reset. Keys issued by the old Magic console no longer work anywhere. Generate a fresh key at 21st.dev/mcp.

What this package does now (v0.2.0+)

npx -y @21st-dev/magic@latest API_KEY="..." still works: since v0.2.0 it is a small stdio proxy that forwards every MCP message to the 21st MCP server. Existing mcp.json entries that reference @21st-dev/magic keep functioning — but they now speak to the same server as the 21st CLI, with the tools available to the authenticated account.

The API key is accepted in all the historical forms: positional API_KEY="...", --API_KEY=..., /API_KEY:..., -API_KEY ..., or the TWENTY_FIRST_API_KEY / API_KEY_21ST environment variables.

AI access

Builder component access does not enable hosted 21st AI. The server lists generate and iterate_generation only when AI access is enabled. Check get_usage.aiGenerationEnabled; this reports access, not the remaining AI credit balance. With AI off, use search and get_component, then adapt the code with your own coding agent. Existing drafts remain readable.

A cached or legacy generation call can return ai_subscription_required. Do not retry until AI is enabled. Refresh the client tool list or reconnect after enabling AI. The proxy forwards discovery to the server, so existing proxy versions receive this behavior without an npm update.

server.json mirrors the official dev.21st/mcp registry listing. The registry version is independent of this compatibility package version.

Old tool names → new tool names

The 21st MCP still accepts the legacy Magic tool names and translates them, so agents that remember the old names keep working. Prefer the new names:

Legacy Magic tool	21st MCP tool
21st_magic_component_builder	generate
21st_magic_component_inspiration	get_inspiration
21st_magic_component_refiner	generate (new generation from the refinement prompt)
logo_search	search_logo (one query per call)

The current server exposes much more than the old four tools: catalog search across components/themes/templates, paid code retrieval, bookmarks, team libraries, UI generation with variants, profile management, and more. Connect and call tools/list to see the tools available to your account.

Install as a plugin

This repository is also packaged as an agent plugin (MCP server + a UI skill). You don't need to wait for any store — this repo IS a marketplace, add it directly:

# Claude Code
claude plugin marketplace add 21st-dev/magic-mcp   # then: /plugin install 21st

# Grok Build
grok plugin marketplace add 21st-dev/magic-mcp && grok plugin install 21st --trust

# Codex CLI
codex plugin marketplace add 21st-dev/magic-mcp    # then install "21st" from /plugins

Set your API key in the API_KEY_21ST variable (free key at 21st.dev/mcp).

Store listings:

• Cursor / Grok Bot — install "21st" from the Cursor Marketplace, then set your API_KEY_21ST under Plugins → Configure. Get a key at 21st.dev/mcp.
• Grok Build — grok plugin install 21st --trust (from the official xAI marketplace), then export API_KEY_21ST.
• Claude Code — the repo carries a .claude-plugin/ manifest: /plugin install it from any marketplace that lists this repo, or load locally with claude --plugin-dir . and export API_KEY_21ST.

The plugin config expects the API key in the API_KEY_21ST variable in every client.

Links

• 21st MCP setup & API keys: https://21st.dev/mcp
• 21st CLI on npm: https://www.npmjs.com/package/@21st-dev/cli
• 21st.dev — discover, publish, and generate UI components: https://21st.dev

FAQ

Why did my old Magic MCP stop working? The Magic backend (magic.21st.dev) was superseded by the unified 21st MCP, and all old API keys were reset for security. Update to a fresh key from 21st.dev/mcp — your existing @21st-dev/magic config will then work again through this compatibility proxy, though we recommend switching to npx @21st-dev/cli@latest init.

Is /ui still a thing? Use natural language: ask your agent to search 21st for components (search), or use hosted UI generation (generate) when AI is enabled. The old /ui, /21 trigger phrases were a convention of the legacy tools' descriptions, not the protocol.