Is WCAG Accessibility MCP free?

Yes, WCAG Accessibility MCP is free to use.

How do I install WCAG Accessibility MCP?

WCAG Accessibility MCP is a local plugin. Install it using npm package: https://www.npmjs.com/package/wcag-accessibility-mcp and add the generated configuration snippet to your AI app's MCP config file. Then restart your AI app.

Is WCAG Accessibility MCP safe to use?

WCAG Accessibility MCP was flagged by MCP Marketplace's security scan, scoring 5.2/10 (elevated risk). It has 3 high or critical findings to review. Review the security report on this page carefully before installing it.

What credentials does WCAG Accessibility MCP need?

WCAG Accessibility MCP requires the following credentials or environment variables: A11Y_MCP_BROWSER_PATH, A11Y_MCP_ALLOWED_ROOT, A11Y_MCP_ALLOW_PRIVATE, A11Y_MCP_ENABLE_FILE_AUDIT. You can find setup instructions on the server detail page.

What AI apps work with WCAG Accessibility MCP?

WCAG Accessibility MCP uses the Model Context Protocol (MCP) and works with any MCP-compatible AI app, including Claude, ChatGPT / Codex, Gemini, Copilot, Cursor, and more.

Back to Browse

WCAG Accessibility MCP MCP Server

by Aditya Sharma

Developer ToolsModerate5.2LocalNew

Free

WCAG accessibility audits for AI agents and generated UIs.

About

WCAG Accessibility MCP is an accessibility testing server for AI coding and design agents. It helps tools like Codex, Claude Code, and other MCP-compatible clients audit generated web interfaces before they are treated as complete.

It runs rendered HTML, URLs, or local HTML files through axe-core, maps findings to WCAG-focused guidance, checks color contrast, suggests passing color fixes, and exposes a complete WCAG A/AA/AAA checklist with automated-vs-manual coverage.

It is built for designers, developers, design engineers, AI product teams, and anyone using AI agents to create web UI.

Security Report

5.2

Moderate5.2Moderate Risk

This accessibility auditing MCP server is well-architected with strong security controls. It properly validates URLs and file paths, restricts network access by default, implements browser sandboxing, and uses read-only operations throughout. Minor code quality observations around error handling do not significantly impact security posture. The server's permissions (network access, file I/O, process spawning for Chromium) are appropriate and proportionate to its stated purpose of rendering and auditing web UIs. Supply chain analysis found 3 known vulnerabilities in dependencies (1 critical, 1 high severity). Package verification found 1 issue (1 critical, 0 high severity).

5 files analyzed · 8 issues found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

File System Read

Reads files on your machine. Normal for tools that analyze or process local data.

File System Write

Writes or modifies files on your machine. Check that this is expected for the tool.

HTTP Network Access

Connects to external APIs or services over the internet.

network_websocket

Check that this permission is expected for this type of plugin.

env_vars

Check that this permission is expected for this type of plugin.

process_spawn

Check that this permission is expected for this type of plugin.

system_info

Check that this permission is expected for this type of plugin.

Unverified package source

We couldn't verify that the installable package matches the reviewed source code. Proceed with caution.

What You'll Need

Set these up before or after installing:

Absolute path to Chrome/Chromium/Edge if auto-detection fails.Optional

Environment variable: A11Y_MCP_BROWSER_PATH

Restricts local file audits to a specific project folder.Optional

Environment variable: A11Y_MCP_ALLOWED_ROOT

Allows localhost/private-network URL targets in trusted environments.Optional

Environment variable: A11Y_MCP_ALLOW_PRIVATE

Enables local file audits over HTTP only for trusted deployments.Optional

Environment variable: A11Y_MCP_ENABLE_FILE_AUDIT

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "wcag-accessibility-mcp": {
      "env": {
        "A11Y_MCP_ALLOWED_ROOT": "your-a11y-mcp-allowed-root-here",
        "A11Y_MCP_BROWSER_PATH": "your-a11y-mcp-browser-path-here",
        "A11Y_MCP_ALLOW_PRIVATE": "your-a11y-mcp-allow-private-here",
        "A11Y_MCP_ENABLE_FILE_AUDIT": "your-a11y-mcp-enable-file-audit-here"
      },
      "args": [
        "-y",
        "wcag-accessibility-mcp"
      ],
      "command": "npx"
    }
  }
}

Getting Started

Once installed, try these example prompts and explore these capabilities:

1"Audit this page at desktop and mobile sizes. Fix critical and serious accessibility issues, then rerun the audit."
2"Check whether this generated HTML passes WCAG 2.2 AA contrast and semantic accessibility checks."
3"Use the WCAG checklist to tell me which accessibility checks still require manual review."
4Tool: audit_url — Audits a rendered web page URL.
5Tool: audit_html — Audits supplied HTML before it is hosted.
6Tool: audit_file — Audits a local .html or .htm file inside an allowed project root.
7Tool: check_contrast — Calculates WCAG contrast for a color pair.
8Tool: suggest_contrast_fix — Suggests a passing foreground or background color.
9Tool: explain_issue — Explains an accessibility rule and how to fix it.
10Tool: get_wcag_checklist — Returns the complete WCAG requirement checklist with automated/manual coverage.

Documentation

View on GitHub

From the project's GitHub README.

A11y Feedback MCP

Give coding and design agents a real accessibility feedback loop instead of another reminder to “follow WCAG.”

a11y-feedback-mcp renders an interface in Chromium, runs axe-core, and returns actionable evidence to any Model Context Protocol client: violated rules, impact, CSS selectors, DOM snippets, computed styles, bounding boxes, remediation steps, and mathematically passing contrast candidates.

It works directly with Codex and Claude Code. For Claude Design, the reliable workflow is to connect Claude Code to both Claude Design's MCP server and this server, then audit the generated HTML or live preview and send corrections back through the design workflow.

This is an automated testing aid, not a WCAG certification service. It deliberately reports incomplete checks and requires human testing for keyboard, focus, screen readers, zoom, motion, cognition, and content quality.

What “live feedback” means

flowchart TD
    A["Agent creates or changes UI"] --> B["Render at target viewport"]
    B --> C["Run axe + contrast analysis"]
    C --> D["Return evidence and correction"]
    D --> E["Agent proposes or applies code fix"]
    E --> F["Re-run same audit"]
    F --> G["Human checks incomplete behavior"]

The server is read-only. It never silently edits a project. The connected agent uses the evidence to make a scoped change, then reruns the audit to verify it.

Tools

Tool	Purpose
`audit_url`	Audit a rendered public or local development URL
`audit_html`	Audit generated HTML before it is hosted
`audit_file`	Audit a local `.html`/`.htm` file inside an allowed project root
`check_contrast`	Calculate WCAG contrast for a color pair and text style
`suggest_contrast_fix`	Propose the smallest black/white-directed color adjustment that passes
`explain_issue`	Turn an axe rule ID into implementation and verification guidance
`get_wcag_checklist`	Return the complete A/AA/AAA criterion set with W3C links and automated/manual coverage

All tools are annotated read-only. The server also exposes an accessibility-fix-loop prompt.

Standards profiles

The audit tools support wcag2a, wcag2aa, wcag2aaa, wcag21aa, wcag21aaa, wcag22aa, wcag22aaa, and best-practice. AA profiles include all required A and AA criteria; AAA profiles include A, AA, and AAA. wcag22aa remains the default because W3C recommends the latest WCAG version and cautions against requiring whole-site AAA as a general policy. Use AAA as an explicit enhanced target and report criterion-level progress.

An axe mapping means partial automated coverage, never that the complete success criterion was tested. get_wcag_checklist exposes all 55 criteria required for WCAG 2.2 AA or all 86 required for WCAG 2.2 AAA, including the manual work automation cannot complete.

Requirements

Node.js 20 or newer
Chrome or Edge recommended
Windows, macOS, or Linux

The server looks for installed Chrome/Edge first. On supported Linux environments it can fall back to the bundled @sparticuz/chromium. You can set A11Y_MCP_BROWSER_PATH to an explicit browser executable. Chromium sandboxing stays enabled by default; set A11Y_MCP_NO_SANDBOX=true only for constrained containers or Lambda-style runtimes that cannot launch Chrome otherwise.

Install on Windows

Open PowerShell in the folder where you keep projects:

git clone https://github.com/aditya-ariosity/a11y-feedback-mcp.git
cd a11y-feedback-mcp
npm install
npm run build

If the repository is not on GitHub yet, download or copy this folder first, then run the final three commands inside it.

Connect Codex

From PowerShell, use the absolute path to the built entry point:

codex mcp add a11y-feedback -- node "C:\full\path\to\a11y-feedback-mcp\dist\index.js"

Or add the equivalent configuration to ~/.codex/config.toml:

[mcp_servers.a11y_feedback]
command = "node"
args = ["C:\\full\\path\\to\\a11y-feedback-mcp\\dist\\index.js"]
startup_timeout_sec = 30
tool_timeout_sec = 90

[mcp_servers.a11y_feedback.env]
A11Y_MCP_ALLOWED_ROOT = "C:\\full\\path\\to\\your-projects"

Restart Codex, then ask:

Audit this page at 1440×900 and 390×844. Fix critical and serious issues, rerun both audits, and list the remaining manual checks.

See docs/codex.md for verification and troubleshooting.

Connect Claude Code

claude mcp add --scope user a11y-feedback -- node "C:\full\path\to\a11y-feedback-mcp\dist\index.js"

Run claude mcp list to confirm the connection. See docs/claude-code-and-design.md for the Claude Design bridge workflow.

Development

npm install
npm run check
npm test
npm run test:e2e
npm run build

npm test covers color math, network protection, remediation, and the MCP contract. npm run test:e2e launches Chromium and audits the intentionally inaccessible fixture.

Start the local stdio server:

npm run dev

Start the optional Streamable HTTP transport:

npm run build
npm run start:http

The endpoint is http://127.0.0.1:3000/mcp; health is http://127.0.0.1:3000/health. HTTP binds to 127.0.0.1 by default.

Environment variables

Variable	Default	Meaning
`A11Y_MCP_BROWSER_PATH`	Auto-detected	Absolute Chrome/Chromium/Edge executable path
`A11Y_MCP_ALLOWED_ROOT`	Server working directory	Only local HTML under this root can be audited
`A11Y_MCP_ALLOW_PRIVATE`	`true` on stdio, `false` on HTTP	Allow localhost/private-network URL targets
`A11Y_MCP_ENABLE_FILE_AUDIT`	`false` on HTTP	Permit local-file audit through HTTP after root restriction
`A11Y_MCP_BROWSER_CONCURRENCY`	`2`	Maximum concurrent Chromium audits
`A11Y_MCP_AUDIT_TIMEOUT_MS`	`25000`	Deadline for the axe audit phase
`A11Y_MCP_NO_SANDBOX`	`false`	Launch Chromium without its sandbox only when the runtime requires it
`HOST` / `A11Y_MCP_HOST`	`127.0.0.1`	HTTP bind address
`A11Y_MCP_ALLOWED_HOSTS`	Localhost names	Comma-separated Host headers accepted by HTTP mode
`A11Y_MCP_BODY_LIMIT`	`4mb`	HTTP JSON body limit; must stay above the `audit_html` schema limit
`PORT`	`3000`	HTTP transport port

Do not expose the reference HTTP server directly to the public internet. Put authentication, TLS, rate limits, request-size limits, and tenant isolation in front of it. Read docs/security.md.

Current scope

The MVP covers rendered web UIs and deterministic contrast calculations. It does not yet inspect native mobile apps, PDFs, canvases, video captions, or raw Claude Design pixels. Planned adapters can add framework-aware patches, screenshot/OCR assistance, design-token integration, CI annotations, and first-class design-canvas connectors without changing the MCP contract.

Project documents

License

MIT

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WCAG Accessibility MCP MCP Server

About

Security Report

Findings (8)Action required

Permissions Required

What You'll Need

How to Install

Getting Started

Documentation

A11y Feedback MCP

What “live feedback” means

Tools

Standards profiles

Requirements

Install on Windows

Connect Codex

Connect Claude Code

Development

Environment variables

Current scope

Project documents

License

Reviews

No reviews yet

More Developer Tools MCP Servers

Fetch

Toleno

mcp-creator-python

MarkItDown

MCP Marketplace

FinAgent