WCAG 2.2 Compliance

wcag-compliance-mcp

MCP server for WCAG 2.2 audits, verified remediation examples, and U.S. accessibility deadlines. Four tools, no API keys, no network calls, all data bundled.

Built from a benchmark that was verified in headless Chromium: 64 fail/pass HTML pairs executed against axe-core 4.14.0, all 87 WCAG 2.2 success criteria, and 21 sourced regulatory dates from the 1990 ADA through the 2028 DOJ Title II deadline.

Listed in the official MCP registry as io.github.Veduis/wcag-compliance-mcp, on the 97k star MCP directory, and in the accessibility tools list.

Tools

Tool	What it answers
audit_html_snippet	Which WCAG 2.2 defects are in this HTML, what is the failing criterion, and what does the fix look like
lookup_wcag_criterion	What does 1.4.3 mean, what level is it, does it apply to ADA Title II entities, and is there an automated rule
get_verified_fix_example	Show me a failing snippet, the corrected snippet, why it matters, and how to test it manually
check_ada_compliance_deadlines	When does my organization have to comply, and what rule sets the date

audit_html_snippet

18 static checks over a fragment or full document:

Check	Success criterion
Image without a text alternative	1.1.1
Image button without alt	1.1.1
role="img" SVG with no name	1.1.1
Link with no accessible name	2.4.4
Button with no accessible name	4.1.2
Form field with no programmatic label	3.3.2
Missing html lang	3.1.1
Missing page title	2.4.2
Skipped heading levels or no h1	1.3.1
Duplicate id values	4.1.1
Positive tabindex	2.4.3
aria-hidden on a focusable element	4.1.2
Non-li children of ul/ol	1.3.1
iframe without title	4.1.2
Data table without th	1.3.1
video without a captions track	1.2.2
Viewport meta blocking zoom	1.4.4
Common-purpose input without autocomplete	1.3.5

Every finding returns the criterion, the offending markup, and a corrected snippet.

check_ada_compliance_deadlines

Entity types: title_ii_large, title_ii_small, title_iii_business, federal_contractor, hhs_recipient, eu_business, ontario.

Pass as_of to compute the answer for any date, which makes the tool useful for retroactive scoping and for legal memos that need to state what applied on a given day. Every date carries its primary source URL.

Install

npx -y github:Veduis/wcag-compliance-mcp

Three other routes:

Route	Command
MCPB bundle (Claude Desktop, one click)	wcag-compliance-mcp.mcpb
Official registry	io.github.Veduis/wcag-compliance-mcp
Docker	docker build -t wcag-compliance-mcp . && docker run -i --rm wcag-compliance-mcp

The npm package wcag-compliance-mcp lands with the next publish. Until then the GitHub spec installs the same code and dependencies.

Claude Desktop

~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "wcag-compliance": {
      "command": "npx",
      "args": ["-y", "github:Veduis/wcag-compliance-mcp"]
    }
  }
}

Cursor

.cursor/mcp.json:

{
  "mcpServers": {
    "wcag-compliance": {
      "command": "npx",
      "args": ["-y", "github:Veduis/wcag-compliance-mcp"]
    }
  }
}

VS Code (Copilot agent mode)

.vscode/mcp.json:

{
  "servers": {
    "wcag-compliance": {
      "command": "npx",
      "args": ["-y", "github:Veduis/wcag-compliance-mcp"]
    }
  }
}

Docker

docker build -t wcag-compliance-mcp .
docker run -i --rm wcag-compliance-mcp

Example

Ask your agent:

Audit this pricing page for WCAG 2.2 issues and give me the corrected markup.

The agent calls audit_html_snippet, then get_verified_fix_example for each failing criterion. What comes back is a failing snippet, the corrected snippet, and the manual test step, not a vague warning.

$ audit_html_snippet('<img src="chart.png">')

{
  "summary": {
    "issues": 1,
    "checks_run": 18,
    "checks_failed": 1,
    "conformance_claim": false
  },
  "findings": [
    {
      "check_id": "img-alt",
      "sc": "1.1.1",
      "level": "A",
      "title": "Image missing a text alternative",
      "count": 1,
      "elements": [
        {
          "snippet": "<img src=\"chart.png\">",
          "reason": "No alt, aria-label, or aria-labelledby. Decorative images need alt=\"\"."
        }
      ],
      "fix": "<img src=\"chart.png\" alt=\"Bar chart: Q3 revenue rose 18 percent over Q2\">"
    }
  ]
}

What automation cannot see

This matters more than the feature list. In the benchmark behind this server, axe-core 4.14.0 flagged 39 of 64 deliberately defective documents. The other 25 needed scripted checks or a human. Across the full standard, 29 of 87 criteria have a mapped rule and 58 have none, and at Level AA, the level the law actually targets, only 7 of 24 criteria have a rule.

So the server reports conformance_claim: false on every audit. A clean result means no static defect was found, not that the page conforms. Contrast, focus visibility, keyboard traps, reading order, captions accuracy, and error recovery all need a rendered page or a person. If you need a full-domain audit with those checks, that is what vComplianceScanner does.

Data provenance

Dataset	DOI
Preprint: what automated testing actually detects	10.5281/zenodo.23829968
64 browser-verified fail/pass pairs, axe-core 4.14.0	10.5281/zenodo.23781867
87 WCAG 2.2 success criteria with rule mapping	10.5281/zenodo.23781861
21 sourced ADA / Section 504 / EAA dates	10.5281/zenodo.23781873
64 multi-turn LLM remediation prompts	10.5281/zenodo.23781879

Mirrors: Hugging Face. Test cases are CC BY 4.0, code is MIT.

Development

npm install
npm test          # 18 checks, including a live stdio handshake
npm start

Layout:

src/index.mjs    MCP server, tool registration, resource
src/checks.mjs   18 static checks, no browser required
src/data.mjs     criteria, pairs, timeline, deadline resolution
data/            bundled JSON, generated from the published datasets
test/smoke.mjs   engine tests plus protocol handshake

More from Veduis

• WCAG 2.2 developer implementation manual
• ADA Title II vs Title III: which law applies to a website
• ADA demand letter defense

License

MIT for the code. Dataset content is CC BY 4.0, attribution to Veduis LLC.