A toolkit for checking whether websites work well for people with disabilities, including users who rely on keyboards or screen readers. It checks parts of WCAG, the international accessibility guidelines for websites.

Use it to check color combinations, scan HTML files, review ARIA labels and landmarks, and assess keyboard navigation and screen-reader support.

It helps find barriers such as poor color contrast, missing labels, incorrect page structure, and controls that cannot be reached by keyboard.

a11y-audit — Skill for Claude Code and Codex by JansenAnalytics

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo

git clone --depth 1 https://github.com/JansenAnalytics/claudex

agentmods

npx agentmods add skills/jansenanalytics/claudex/a11y-audit

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/jansenanalytics/claudex/a11y-audit/github.svg)](https://agentmods.dev/skills/jansenanalytics/claudex/a11y-audit)

Your own site

<a href="https://agentmods.dev/skills/jansenanalytics/claudex/a11y-audit"><img src="https://agentmods.dev/badge/skills/jansenanalytics/claudex/a11y-audit/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/jansenanalytics/claudex/a11y-audit"><img src="https://agentmods.dev/badge/skills/jansenanalytics/claudex/a11y-audit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 884 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00031	$0.00884
Opus 5.5	$0.00012	$0.00354
Sonnet 5.5	$0.00006	$0.00177
Haiku 4.5	$0.00003	$0.00088

Measured 1mo ago against content hash be2960589249, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

a11y-audit scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/a11y-audit/SKILL.md · 117 lines

How it starts

The opening of the file, as written. The whole thing — 117 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Accessibility auditing: WCAG compliance checking, contrast ratios, ARIA labels, keyboard navigation, semantic HTML, screen reader compatibility.

Use When

Auditing web pages for accessibility compliance
Checking color contrast ratios against WCAG standards
Verifying ARIA attributes and landmark usage
Ensuring keyboard navigability
Meeting WCAG 2.1 AA standards
Reviewing HTML for semantic correctness and screen reader compatibility

Scripts

contrast-checker.py

Calculates WCAG contrast ratios between foreground and background colors. Pure Python, no dependencies.

Single pair:

python3 scripts/contrast-checker.py --fg "#333333" --bg "#ffffff"

Batch mode (reads JSON file with array of {"fg": "#hex", "bg": "#hex", "label": "optional"} objects):

python3 scripts/contrast-checker.py --batch colors.json

Output includes:

Contrast ratio (e.g., 12.63:1)
Pass/fail for AA normal text (≥4.5:1), AA large text (≥3:1)
Pass/fail for AAA normal text (≥7:1), AAA large text (≥4.5:1)

html-a11y-scan.py

Scans an HTML file for common accessibility issues. Uses Python's built-in html.parser.

python3 scripts/html-a11y-scan.py page.html
python3 scripts/html-a11y-scan.py page.html --format json
python3 scripts/html-a11y-scan.py page.html --format text

Checks for:

Images without alt attributes (critical)
Form inputs without labels or aria-label (critical)
Missing lang attribute on <html> (critical)
Empty links or buttons (warning)
Skipped heading levels (warning)
Tables without <th> headers (warning)
Missing ARIA landmarks: main, nav, banner, contentinfo (info)

Output (JSON by default): array of issues with severity, element, line, issue, and suggestion fields.

keyboard-nav-checklist.sh

Generates a Markdown checklist for manual keyboard navigation testing.

bash scripts/keyboard-nav-checklist.sh
bash scripts/keyboard-nav-checklist.sh --output checklist.md

Read the full file on GitHub · 117 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

1mo ago First seen · 117 lines · 31 tokens per session scan A be2960589249

Subscribe to this mod's changes

a11y-audit is a skill published in the GitHub repository JansenAnalytics/claudex (5 stars, last pushed 4mo ago), licensed MIT. It adds 31 tokens to every session and 884 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Design and UX Frontend accessibility aria contrast-ratio keyboard-nav wcag

accessibility

Use when making a web UI conform to WCAG 2.2 Level AA — axe-core or Lighthouse a11y violations, keyboard operability, focus management, ARIA roles/names/live regions, contrast, tap-target size. NOT palette or visual intent (that is design), NOT test-runner setup (that is testing-web), NOT LCP/page-speed (that is…

ericrisco/rsc-harness · 86 tokens

accessibility-expert

Build interfaces usable by everyone: WCAG 2.2 conformance, semantic HTML, ARIA, keyboard navigation, screen readers and accessible forms. Use when the user mentions accessibility, a11y, WCAG, ARIA, screen readers, keyboard navigation, colour contrast, focus management, the European Accessibility Act or Section 508, or…

personamanagmentlayer/pcl · 98 tokens

accessibility-engineer

You are the Accessibility Engineering Specialist. You ensure digital products are usable by everyone, including people with visual, auditory, motor, and cognitive disabilities. You audit against WCAG 2.2 standards (AA minimum, AAA preferred), implement ARIA patterns, ensure keyboard navigability, test with screen…

buiphucminhtam/forgewright · 61 tokens

a11y-audit