Spectrum UI MCP

What it does

The Spectrum UI MCP server is the component library's own bridge to coding assistants. It reads the public Spectrum UI registry index (a JSON list of every installable component, hosted on spectrumhq.in) and exposes it as five tools: listing components by category, keyword search, full details for one component, a category count, and an installer.

The installer does not copy files itself. It shells out to the shadcn CLI in your project folder, trying `bunx --bun shadcn@latest add @spectrumui/<name>` first and falling back to `npx shadcn@latest add @spectrumui/<name>`, with a 120-second timeout on each attempt. So an assistant can go from "find me a kanban board" to the component's files in your codebase in one conversation.

One thing the README does not mention: the published 0.1.1 package sends anonymous usage events (event name, the search text or component name typed, and whether a match was found) to https://spectrumhq.in/api/mcp-events on searches and lookups. Setting SPECTRUM_NO_TELEMETRY=1 or DO_NOT_TRACK=1 turns this off (dist/utils/telemetry.js in 0.1.1).

What it needs

Node.js 18 or newer (npx). Network access to spectrumhq.in to load the component registry. For install_component, a project already set up with Next.js, Tailwind CSS and shadcn/ui; Bun is optional and used first when present. No account or key.

Limits

Only covers Spectrum UI's own components, not shadcn/ui or other registries. search_components returns 8 results by default, up to 20 with `limit`. In 0.1.1 the registry is fetched once per session and kept in memory, so components published while the editor stays open do not appear until restart; the registry address is fixed. A configurable registry (SPECTRUM_REGISTRY_URL) and a 5-minute cache exist only on the main branch, not in the published package. install_component fails if the shadcn CLI cannot run in the target folder.

Who it suits

Suits developers already using Spectrum UI (or a Next.js + Tailwind + shadcn/ui project that wants its components) who want their assistant to find and add components without copying code by hand. It runs locally, needs no sign-in, and is published by the library's own maker. It is of no use outside that stack; anyone who wants an assistant limited to reading component docs should note that one tool runs package commands in the project folder.