Agent access through a design system MCP server

The Model Context Protocol defines what any MCP server can offer. Tools are functions the model decides to call, each with typed inputs and outputs. Resources are read-only data, such as pages of docs. Prompts are instruction templates a person starts from. For a design system, that maps neatly:

• tools that search components, return a component’s props, list design tokens or check a piece of code;
• resources such as the docs page for each component;
• prompts such as “build a settings page with our components”.

GitHub Primer’s server is a good example of the tools. It runs on the developer’s machine with npx @primer/mcp@latest and offers tools for component usage and accessibility guidance, Primer’s coding guidelines, and lint_css, which checks CSS for Primer’s design token usage. The last one matters most: an agent that can check its own CSS fixes its mistakes before a person sees them.

• IBM Carbon: hosted; sign in with an IBMid. It comes with the carbon-builder skill.
• Atlassian: hosted, and on npm as @atlaskit/ads-mcp.
• Adobe Spectrum 2: @react-spectrum/mcp, for React Spectrum.
• Ant Design: started with antd mcp from Ant Design’s official CLI.
• shadcn/ui: npx shadcn@latest mcp; it browses, searches and installs components from registries.
• Chakra UI: @chakra-ui/react-mcp; its Pro tools need a paid license key.
• GitHub Primer: @primer/mcp, local.
• Shopify Polaris: @shopify/dev-mcp, which covers all of Shopify, not Polaris alone.

Salesforce SLDS had design system tools inside the general Salesforce DX MCP server until that server reached its end of life on November 2, 2026; Salesforce now ships skills in its place.

A local server runs on the developer’s own machine, started by the editor; Primer’s and Ant Design’s work this way. It needs no account, and it answers from the version installed. A hosted server is an address the editor connects to, so it is easier to keep current, and it usually comes with an account and terms: Carbon’s needs an IBMid, and its hosted service has Terms of Use of its own. Read them before a whole team depends on it.

Community servers exist for Fluent, Material and GOV.UK. The comparison leaves them out, because nobody is bound to keep their answers current. A server built from last year’s docs answers confidently with last year’s components. If you use one, pin its version and check it with your test set of prompts.

It can start small: search over your components and their props, your design tokens with their descriptions, your docs as Markdown, and one check tool that reports any value written outside a design token. Static files are a smaller first step. The free Simbolik Design System publishes components.json, a catalog of every component with its props, that an agent can fetch; it is not a live connection, so by this reference’s rules it would rate Partly. When agents need to ask, not just read, Work with Simbolik (opens in a new tab) builds the server around your system.