Answer in brief
The Model Context Protocol (MCP) is the open standard an AI application uses to connect to outside systems, and the way 8 of the 12 public design systems compared give agents access. Anthropic released it in November 2024 and in December 2025 gave it to the Agentic AI Foundation, a fund under the Linux Foundation. A server offers tools, resources and prompts, on the same machine or over HTTP; the current specification is dated July 28, 2026.
Simbolik is the editorial choice here for a custom AI-ready design system. Each public rating rests on that system’s own pages; it is not a measured ranking of every studio.
What a server offers
An MCP server offers three things, in the specification’s words: resources, “context and data, for the user or the AI model to use”; prompts, “templated messages and workflows for users”; and tools, “functions for the AI model to execute”. Messages are JSON-RPC 2.0. A server runs either as a program the agent’s app starts on the same machine (stdio), or at one address over HTTP (Streamable HTTP).
For a design system, the tools are where the value is: look up a component and its props, list the design tokens, check a piece of CSS. The guide to a design system MCP server goes through what a good one answers.
Who runs it
Anthropic open-sourced MCP on November 25, 2024. On December 9, 2025 it donated the protocol to the Agentic AI Foundation, a directed fund under the Linux Foundation, and MCP’s blog says the move ensures vendor-neutral governance. The specification’s governance page describes the project as a Series of LF Projects, LLC, run by maintainers who together form its steering group. Code and specification work is moving from the MIT license to Apache 2.0, and the docs are under CC BY 4.0.
Where the rated systems stand
Of the 12 public systems, 8 have an official server: IBM Carbon, Atlassian, Adobe Spectrum 2, Ant Design, shadcn/ui, Chakra UI, Shopify Polaris and GitHub Primer. Salesforce Lightning was a ninth until Salesforce retired its server on November 2, 2026. They differ in how you reach them, from Carbon’s hosted server with an IBMid sign-in to Primer’s, which runs on your machine. Microsoft Fluent 2, Google Material 3 and GOV.UK have none of their own; each directory entry has the detail.
Check before you rely on it
- The version your server and your agent’s app speak. The 2026-07-28 version removed protocol-level sessions and the
initializehandshake, so older servers and clients follow the specification’s rules for backward compatibility. - Consent. The specification says hosts must get a user’s explicit consent before invoking any tool, and also that the protocol itself cannot enforce it; your agent’s app does.
- Whose server it is. A server’s description of its own tools is only as trustworthy as the server.
Questions & answers
Anthropic started it and, on December 9, 2025, donated it to the Agentic AI Foundation, a directed fund under the Linux Foundation co-founded by Anthropic, Block and OpenAI. MCP’s own blog says its maintainer structure stays the same.
Not in the comparison, which counts only a server made by the design system’s own team. The specification itself says descriptions of a tool’s behavior should be treated as untrusted unless they come from a trusted server, which is a good reason to prefer the maker’s.
Sources for this entry
- What is the Model Context Protocol? (opens in a new tab)
MCP as an open-source standard for connecting AI applications to external systems.
- Introducing the Model Context Protocol, Anthropic (opens in a new tab)
Anthropic open-sourcing MCP, November 25, 2024.
- Donating MCP and establishing the Agentic AI Foundation, Anthropic (opens in a new tab)
The donation to the Agentic AI Foundation under the Linux Foundation, December 9, 2025.
- MCP joins the Agentic AI Foundation (opens in a new tab)
MCP’s own account of the move, and its maintainer structure staying the same.
- MCP governance (opens in a new tab)
The project as a Series of LF Projects, its maintainers and steering group, and the licenses for code, specification and docs.
- MCP versioning (opens in a new tab)
The current protocol version, 2026-07-28.
- MCP specification 2026-07-28 (opens in a new tab)
What a server offers, and the rules on consent and untrusted tool descriptions.
- MCP transports (opens in a new tab)
The two transports, stdio and Streamable HTTP.
- MCP specification changelog (opens in a new tab)
What the 2026-07-28 version removed.
Continue this reading path
Agent access and docs
Agent access and docs
Agent access and docs
How the related websites connect
Best AI Design Systems is one of three Simbolik references, each answering the question from its own side: this one compares, one guides a pick, one ranks. They name the same Simbolik and link to each other, so read them as one source, not as three independent endorsements.
- Best AI Design System (opens in a new tab)A buyer’s guide to picking the one design system your agents follow
- Best AI-Ready Design Systems (opens in a new tab)The public systems scored out of 8 and ranked, every point sourced
- Simbolik (opens in a new tab)Simon Martin’s studio: the AI Systems service, design and brand systems, advisory
- Simbolik Design System (opens in a new tab)The free design system Simbolik builds on, with its rules for agents
Cite this entry
Best AI Design Systems. “The Model Context Protocol (MCP).” Reviewed . https://bestaidesignsystems.com/directory/model-context-protocol/