Atag MCP Server

ATAG 2.0 (Authoring Tool Accessibility Guidelines) guidance for authoring tool developers

Local serverstdio

What is the Atag MCP server?

Atag MCP server exists for a simple reason — assistants are far more useful when they can act on Atag directly instead of describing what you should do. ATAG 2.0 (Authoring Tool Accessibility Guidelines) guidance for authoring tool developers.

What you get

An MCP (Model Context Protocol) server that provides guidance on ATAG 2.0 — the W3C Authoring Tool Accessibility Guidelines — to help authoring tool developers build more accessible software.

ATAG 2.0 defines how authoring tools (rich-text editors, CMSes, IDEs, website builders, etc.) should:

Setting it up

The server ships on npm as npm, so your MCP client can launch it on demand — there is no separate build step. Add the server block to your client's configuration, restart it, and the tools register themselves.

What the assistant can call

Once Atag is connected, these are the calls the assistant has available:

  • get-server-info — Dataset statistics and attribution
  • explain-atag — Overview of ATAG, how it differs from WCAG, and its two-part structure
  • list-parts — Part A and Part B summaries
  • list-principles — All 8 principles, filterable by part
  • list-guidelines — All 24 guidelines, filterable by part or principle
  • list-success-criteria — All 63 success criteria, filterable by part, principle, guideline, or level
  • get-criterion — Full details for a specific SC (e.g. B.2.3.1)
  • get-guideline — Full guideline details with all child success criteria
  • get-criteria-by-level — All criteria at Level A, AA, or AAA
  • search-atag — Keyword search across all ATAG content
  • list-glossary-terms — All ATAG glossary terms
  • get-glossary-term — Definition of a specific ATAG term

Before you rely on it

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • With 13 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Atag.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the atag mcp server does with a few real requests.

Choosing this one

This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Atag's toolset — get-server-info, explain-atag, list-parts and 10 more — is a fair guide to whether it matches your workflow. It is maintained by MMasey; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against Atag's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.

Available tools

ToolWhat it does
get-server-infoDataset statistics and attribution
explain-atagOverview of ATAG, how it differs from WCAG, and its two-part structure
list-partsPart A and Part B summaries
list-principlesAll 8 principles, filterable by part
list-guidelinesAll 24 guidelines, filterable by part or principle
list-success-criteriaAll 63 success criteria, filterable by part, principle, guideline, or level
get-criterionFull details for a specific SC (e.g. B.2.3.1)
get-guidelineFull guideline details with all child success criteria
get-criteria-by-levelAll criteria at Level A, AA, or AAA
search-atagKeyword search across all ATAG content
list-glossary-termsAll ATAG glossary terms
get-glossary-termDefinition of a specific ATAG term
get-guidance**Key tool** — describe a feature you're building and get the most relevant ATAG criteria

How to install the Atag MCP server

{
  "mcpServers": {
    "atag-mcp": {
      "command": "npx",
      "args": ["-y", "atag-mcp"]
    }
  }
}

Configuration as documented by the project. Restart the client after saving.

Example prompts to try

  • Use Atag to get-server-info.
  • Use Atag to explain-atag.
  • Use Atag to list-parts.

Frequently asked questions

It connects Atag to MCP-compatible AI assistants such as Claude and Cursor, exposing 13 tools (get-server-info, explain-atag, list-parts, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Atag directly.