web-accessibility-a11y

web-accessibility-a11y is a skill for Claude Code, Codex from plugin87/full-stack-design-skills. It costs 116 tokens per session (3,254 once invoked), scanned A, original, MIT.

A guide to making websites usable by people with different abilities, including people who use screen readers, keyboards, or other assistive technology. It covers WCAG, a widely used set of web accessibility guidelines.

In plain words
What is it for?
Use it when building or reviewing semantic HTML, forms, dialogs, keyboard navigation, ARIA attributes, screen-reader behavior, color contrast, captions, or accessibility compliance.
Why use it?
It helps prevent interfaces that exclude people because of missing labels, poor contrast, inaccessible keyboard controls, or content that cannot be perceived in another way.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/plugin87/full-stack-design-skills/web-accessibility-a11y
Any agent
npx skills add plugin87/full-stack-design-skills --skill web-accessibility-a11y
Clone the repo
git clone --depth 1 https://github.com/plugin87/full-stack-design-skills

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.

agentmods badge for web-accessibility-a11y

README.md
[![agentmods](https://agentmods.dev/badge/skills/plugin87/full-stack-design-skills/web-accessibility-a11y.svg)](https://agentmods.dev/skills/plugin87/full-stack-design-skills/web-accessibility-a11y)
Your own site
<a href="https://agentmods.dev/skills/plugin87/full-stack-design-skills/web-accessibility-a11y"><img src="https://agentmods.dev/badge/skills/plugin87/full-stack-design-skills/web-accessibility-a11y.svg" alt="Measured on agentmods" height="20"></a>
Per session 116 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,254 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00116 $0.03254
Opus 5 $0.00058 $0.01627
Sonnet 5 $0.00023 $0.00651
Haiku 4.5 $0.00012 $0.00325

Measured 3d ago against content hash c229f2b5adae, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

web-accessibility-a11y 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 3d 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.

.claude/skills/web-accessibility-a11y/SKILL.md · 382 lines

How it starts

The opening of the file, as written. The whole thing — 382 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Web Accessibility (a11y)

A practical guide to building digital products that work for everyone, regardless of ability.

Accessibility is not an afterthought—it's a foundational design principle. This skill covers the technical standards (WCAG 2.1) and practical patterns for building inclusive web experiences.

Why Accessibility Matters

Legal: WCAG 2.1 compliance is increasingly required (ADA, ATAG, EN 301 549, UK EQA).

Business: ~15% of the global population has a disability. Accessible design benefits everyone (captions help in noisy environments, voice control helps people with mobility issues, clear navigation helps users with cognitive disabilities).

Technical: Accessible patterns are often better for SEO, performance, and maintainability.


Core Principles: WCAG 2.1

WCAG (Web Content Accessibility Guidelines) has four principles, abbreviated as POUR:

1. Perceivable

Information must be perceivable—users must be able to see, hear, or otherwise sense it.

Guidelines:

  • Text alternatives — Images need alt text
  • Captions & transcripts — Audio/video needs text
  • Adaptable content — Info not lost when zoomed or reflow
  • Distinguishable — Text is readable (4.5:1 contrast, font size ≥12px)

2. Operable

Interfaces must be operable—users must be able to navigate and interact.

Guidelines:

  • Keyboard accessible — All functions available via keyboard
  • Enough time — Users can pause auto-playing content
  • Seizure prevention — No flashing/flickering (3+ times/second)
  • Navigable — Clear landmarks, skip links, heading hierarchy

3. Understandable

Content and operation must be understandable.

Guidelines:

  • Readable — Clear language, short sentences, defined jargon
  • Predictable — Consistent navigation, no surprises
  • Input assistance — Form errors are identified and labeled clearly

4. Robust

Code must be robust—compatible with assistive technologies.

Guidelines:

  • Valid HTML — Correct use of semantic elements
  • ARIA correctly — Only use ARIA when HTML can't do it
  • Naming, role, value — Every interactive element has a label (name), is understood (role), and exposes state (value)

Read the full file on GitHub · 382 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

  1. 3d ago First seen · 382 lines · 0 tokens per session scan A c229f2b5adae

Subscribe to this mod's changes

web-accessibility-a11y is a skill published in the GitHub repository plugin87/full-stack-design-skills (10 stars, last pushed 1mo ago), licensed MIT. It adds 116 tokens to every session and 3,254 once invoked, about $0.0006 per session on Opus 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.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

brainstorming

You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.

obra/superpowers · 37 tokens

auto-perf-optimize

Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.

microsoft/vscode · 62 tokens

chat-perf

Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.

microsoft/vscode · 51 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens