Summary
This server gives Claude five tools to audit web accessibility in HTML: check_alt_text scans images for missing or weak alt attributes, check_heading_hierarchy validates h1-h6 nesting and outputs a visual tree, check_color_contrast calculates WCAG contrast ratios for color pairs, validate_aria catches role misuse and missing properties, and check_form_accessibility ensures inputs have labels and fieldsets. You'd reach for this when reviewing markup for compliance issues or teaching an agent to spot common accessibility problems like unlabeled form fields, skipped heading levels, or aria-hidden on focusable elements. It runs over stdio and returns structured findings rather than browser automation.
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one prompt install →mcp-a11y-tools
Web accessibility analysis tools for AI agents, served over the Model Context Protocol (MCP).
Tools
check_alt_text
Analyze images in HTML for missing, empty, or low-quality alt text.
- Detects missing
altattributes - Identifies decorative images (
alt=""withrole="presentation") - Flags low-quality alt text (e.g., "image", "photo", filenames)
- Checks linked images,
<input type="image">, and<area>elements
check_heading_hierarchy
Validate heading structure for proper nesting and content quality.
- Verifies h1-h6 order with no skipped levels
- Ensures a single
<h1>per page - Detects empty, too-short, or too-long headings
- Supports
role="heading"witharia-level - Returns a visual tree of the heading outline
check_color_contrast
Check WCAG 2.x contrast ratio for foreground/background color pairs.
- Calculates precise contrast ratio per WCAG relative luminance formula
- Reports AA and AAA compliance for normal and large text
- Accepts hex (
#fff,#ffffff),rgb(r,g,b), and named colors
validate_aria
Validate ARIA attributes on HTML elements.
- Detects invalid ARIA roles
- Checks for missing required ARIA properties per role
- Flags redundant ARIA roles that match native semantics
- Warns about
aria-labelon non-interactive elements - Catches
aria-hidden="true"on focusable elements
check_form_accessibility
Audit form elements for accessibility compliance.
- Verifies every input has an associated label (explicit, implicit, or ARIA)
- Checks radio/checkbox groups for
<fieldset>and<legend> - Flags placeholder text used as the only label
- Suggests
autocompleteattributes for personal info fields - Detects duplicate IDs that break label association
Setup
npm install
npm run build
Usage with Claude Desktop
Add to your claude_desktop_config.json:
{
"mcpServers": {
"a11y-tools": {
"command": "node",
"args": ["D:/products/mcp-servers/mcp-a11y-tools/dist/index.js"]
}
}
}
License
MIT
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Plug Mailtrap into your AI workflow and let it handle the email.
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one prompt install →