The agent harness performance optimization system. Skills, instincts, memory, security, and research-first development for Claude Code, Codex, Opencode, Cursor and beyond.
Magic MCP
It's like v0, but in your Cursor / Claude Code / Windsurf: search 10,000+ React/Tailwind components, generate new UI with AI, and publish your own — right from your editor.…
Install
npx @21st-dev/cli@latest init --client cursorclaude mcp add magic-mcp -- npx @21st-dev/cli@latest init --client cursor{
"mcpServers": {
"magic-mcp": {
"command": "npx",
"args": [
"@21st-dev/cli@latest",
"init",
"--client",
"cursor"
]
}
}
}Install command taken from the project's README or registry entry. Always review code before running it.
README excerpt
Read full README on GitHub →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@21st-dev/magic) has been replaced by the unified 21st MCP, installed via the 21st CLI — setup at 21st.dev/mcp.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
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