Web Interface Guidelines Reviewer
vercel-labs/openreview
Review UI code for Web Interface Guidelines compliance. Use when asked to "review my UI", "check accessibility", "audit design", "review UX", or "check my…
WCAG 2.1/2.2 accessibility verification checklist and automated audit methodology skill.
Install Wcag Checker
$ npx skills add revfactory/harness-100 --skill wcag-checker -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install revfactory/harness-100 wcag-checker --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .claude/skills && cp -r skills-src/en/36-design-system/.claude/skills/wcag-checker .claude/skills/wcag-checker && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "wcag-checker" agent skill from https://github.com/revfactory/harness-100/tree/main/en/36-design-system/.claude/skills/wcag-checker into .claude/skills/wcag-checker/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "wcag-checker", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/revfactory/harness-100/tree/main/en/36-design-system/.claude/skills/wcag-checkerType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add revfactory/harness-100 --skill wcag-checker -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install revfactory/harness-100 wcag-checker --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .agents/skills && cp -r skills-src/en/36-design-system/.claude/skills/wcag-checker .agents/skills/wcag-checker && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "wcag-checker" agent skill from https://github.com/revfactory/harness-100/tree/main/en/36-design-system/.claude/skills/wcag-checker into .agents/skills/wcag-checker/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "wcag-checker", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add revfactory/harness-100 --skill wcag-checker -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install revfactory/harness-100 wcag-checker --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/en/36-design-system/.claude/skills/wcag-checker .cursor/skills/wcag-checker && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "wcag-checker" agent skill from https://github.com/revfactory/harness-100/tree/main/en/36-design-system/.claude/skills/wcag-checker into .cursor/skills/wcag-checker/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "wcag-checker", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/revfactory/harness-100.git --path en/36-design-system/.claude/skills/wcag-checker--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add revfactory/harness-100 --skill wcag-checker -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install revfactory/harness-100 wcag-checker --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/en/36-design-system/.claude/skills/wcag-checker .gemini/skills/wcag-checker && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "wcag-checker" agent skill from https://github.com/revfactory/harness-100/tree/main/en/36-design-system/.claude/skills/wcag-checker into .gemini/skills/wcag-checker/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "wcag-checker", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install revfactory/harness-100 wcag-checkerInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add revfactory/harness-100 --skill wcag-checker -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .github/skills && cp -r skills-src/en/36-design-system/.claude/skills/wcag-checker .github/skills/wcag-checker && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "wcag-checker" agent skill from https://github.com/revfactory/harness-100/tree/main/en/36-design-system/.claude/skills/wcag-checker into .github/skills/wcag-checker/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "wcag-checker", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add revfactory/harness-100 --skill wcag-checker -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install revfactory/harness-100 wcag-checker --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/en/36-design-system/.claude/skills/wcag-checker .opencode/skills/wcag-checker && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "wcag-checker" agent skill from https://github.com/revfactory/harness-100/tree/main/en/36-design-system/.claude/skills/wcag-checker into .opencode/skills/wcag-checker/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "wcag-checker", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
wcag-checker- GitHub stars
- 1.3k
- Token cost
- ~1.4k tokens
- SKILL.md length
- 329 words
- Files
- 1
- Skills in repo
- 464
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
WCAG 2.1/2.2 accessibility verification checklist and automated audit methodology skill.
- Works in 4 steps: Perceivable → Operable → Understandable → …
- Requests like verify accessibility
- SKILL.md covers Target Agents, WCAG 2.1 AA Mandatory Criteria…, Contrast Ratio Calculation… and Per-Component ARIA Patterns, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Wcag Checker is an agent skill from revfactory/harness-100. WCAG 2.1/2.2 accessibility verification checklist and automated audit methodology skill. Use for requests like 'verify accessibility', 'WCAG check', 'check contrast ratio', 'ARIA audit', 'keyboard accessibility', 'screen reader test', etc. Note: running actual assistive technology (JAWS/NVDA), legal consultation, and accessibility certification issuance are outside the scope of this skill.
Its SKILL.md is about 1.4k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Frontend & Design, covering Accessibility. The licence is Apache-2.0.
When your agent uses it
- Requests like verify accessibility
- Check contrast ratio
- Keyboard accessibility
- Screen reader test
Example prompts
- “verify accessibility”
- “WCAG check”
- “check contrast ratio”
- “/wcag-checker”
Workflow steps
4 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 8e8d35c. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are html and markdown).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Wcag Checker loads about 1.4k tokens when it runs. Until then it costs about 101 tokens; SKILL.md has 329 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from revfactory/harness-100 at commit 8e8d35c, republished under its Apache-2.0 licence (© revfactory). 329 words, ~1,405 tokens.
Download SKILL.mdSave it as
.claude/skills/wcag-checker/SKILL.md (or your agent's skills folder).- name
- wcag-checker
- description
- WCAG 2.1/2.2 accessibility verification checklist and automated audit methodology skill. Use for requests like 'verify accessibility', 'WCAG check', 'check contrast ratio', 'ARIA audit', 'keyboard accessibility', 'screen reader test', etc. Note: running actual assistive technology (JAWS/NVDA), legal consultation, and accessibility certification issuance are outside the scope of this skill.
WCAG Checker — Accessibility Verification Checklist + Tools
A domain knowledge skill that enhances the a11y-auditor agent's accessibility verification capabilities.
Target Agents
- a11y-auditor — Uses this skill's checklist and formulas to verify per-component accessibility
- component-developer — Checks accessibility requirements proactively during development
WCAG 2.1 AA Mandatory Criteria Checklist
1. Perceivable
| Criterion | Item | Verification Method | Severity |
|---|---|---|---|
| 1.1.1 | Alt text for non-text content | img has alt, decorative images have alt="" | P0 |
| 1.3.1 | Info and relationships programmatically determined | Semantic HTML, ARIA roles | P0 |
| 1.3.2 | Meaningful sequence | DOM order = visual order | P1 |
| 1.4.1 | Color not sole means of conveying info | Supplemented with icons/text | P0 |
| 1.4.3 | Contrast ratio minimum 4.5:1 (normal), 3:1 (large) | Contrast ratio formula calculation | P0 |
| 1.4.4 | No content loss at 200% zoom | Use rem/em units | P1 |
| 1.4.11 | Non-text UI contrast ratio 3:1+ | Focus rings, borders, icons | P0 |
2. Operable
| Criterion | Item | Verification Method | Severity |
|---|---|---|---|
| 2.1.1 | Keyboard accessible | Tab/Enter/Space/Esc/Arrow behavior | P0 |
| 2.1.2 | No keyboard trap | Tab out possible from all elements | P0 |
| 2.4.3 | Logical focus order | No positive tabindex values | P0 |
| 2.4.7 | Visual focus indicator | :focus-visible styling | P0 |
3. Understandable
| Criterion | Item | Verification Method | Severity |
|---|---|---|---|
| 3.1.1 | Page language specified | <html lang="en"> | P0 |
| 3.2.1 | No context change on focus | Focus alone must not trigger navigation | P0 |
| 3.3.1 | Error identification text provided | Text error messages beyond color alone | P0 |
| 3.3.2 | Labels or instructions | <label> association; no placeholder-only usage | P0 |
4. Robust
| Criterion | Item | Verification Method | Severity |
|---|---|---|---|
| 4.1.2 | Name, role, value programmatically determined | ARIA attribute accuracy | P0 |
| 4.1.3 | Status messages conveyed to assistive technology | aria-live, role="status" | P1 |
Contrast Ratio Calculation Formula
Relative Luminance
L = 0.2126 * R_lin + 0.7152 * G_lin + 0.0722 * B_lin
Where:
- Normalize sRGB to 0-1 (e.g., #FF -> 1.0)
- C_lin = C_srgb <= 0.04045 ? C_srgb/12.92 : ((C_srgb+0.055)/1.055)^2.4Contrast Ratio Formula
CR = (L_lighter + 0.05) / (L_darker + 0.05)
AA criteria:
- Normal text (< 18pt or < 14pt bold): CR >= 4.5
- Large text (>= 18pt or >= 14pt bold): CR >= 3.0
- UI components/graphics: CR >= 3.0
AAA criteria:
- Normal text: CR >= 7.0
- Large text: CR >= 4.5Auto-Adjustment When Contrast Not Met
1. Calculate contrast ratio of current foreground and background
2. If CR < target:
a. Adjust L only in HSL color space to preserve hue
b. Back-calculate L_target: (L_fg + 0.05) / target_CR - 0.05
3. Report both pre- and post-adjustment colorsPer-Component ARIA Patterns
Button
<button type="button" aria-label="Close" aria-pressed="false">
<svg aria-hidden="true">...</svg>
</button>Modal/Dialog
<div role="dialog" aria-modal="true" aria-labelledby="title-id">
<h2 id="title-id">Title</h2>
<!-- Focus trap: Tab cycles within dialog only -->
<!-- Close with Esc, return focus to trigger element on close -->
</div>Select/Combobox
<div role="combobox" aria-expanded="false" aria-haspopup="listbox">
<input aria-autocomplete="list" aria-controls="listbox-id" />
<ul id="listbox-id" role="listbox">
<li role="option" aria-selected="true">Option 1</li>
</ul>
</div>Tab
<div role="tablist" aria-label="Settings">
<button role="tab" aria-selected="true" aria-controls="panel-1">Tab 1</button>
</div>
<div role="tabpanel" id="panel-1" aria-labelledby="tab-1">Content</div>Keyboard Interaction Matrix
| Component | Tab | Enter | Space | Esc | Arrow | Home/End |
|---|---|---|---|---|---|---|
| Button | Focus | Click | Click | - | - | - |
| Checkbox | Focus | Toggle | Toggle | - | - | - |
| Radio | Group focus | Select | Select | - | Cycle | First/Last |
| Select | Focus | Open | Open | Close | Move items | First/Last |
| Modal | Cycle within | - | - | Close | - | - |
| Tab | Tab focus | Activate | Activate | - | Move tabs | First/Last |
| Menu | Focus | Open/Execute | Open/Execute | Close | Move items | First/Last |
| Slider | Focus | - | - | - | Adjust value | Min/Max |
Verification Report Template
## Accessibility Verification Report
### Summary
- Verification Level: WCAG 2.1 AA
- P0 Issues: N (release blocker)
- P1 Issues: N (recommended)
### P0 Issues (Must Fix)
| # | Component | Criterion | Issue | Fix Proposal |
### Contrast Ratio Matrix
| Foreground | Background | Contrast Ratio | AA Normal | AA Large |
### Keyboard Test Results
| Component | Tab | Enter | Space | Esc | Arrow | Result |© revfactory, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in en/36-design-system/.claude/skills/wcag-checker of revfactory/harness-100.
Open the folder on GitHubat commit 8e8d35c
Compare with similar skills
Wcag Checker next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Wcag Checker this skillrevfactory/harness-100 | 1.3k | — | ~1.4k | Automated safety check: Pass | Apache-2.0 | |
| Web Interface Guidelines Reviewervercel-labs/openreview | 1.7k | 97 repos | ~308 | Automated safety check: Pass | None | |
| Accessibility Reviewmarkmead/hyperui | 12k | 1 repos | ~1.1k | Automated safety check: Pass | MIT | |
| Web Animation DesignbaptisteArno/typebot.io | 11k | 2 repos | ~2.7k | Automated safety check: Pass | Custom licence | |
| Accessibility Fixeribelick/ui-skills | 9.5k | 4 repos | ~1.2k | Automated safety check: Pass | MIT | |
| Wcag Audit PatternsvmDeshpande/ai-agent-automation | 178 | 11 repos | ~610 | Automated safety check: Pass | Apache-2.0 |
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Related
Categories
Questions about Wcag Checker
What does Wcag Checker do?
WCAG 2.1/2.2 accessibility verification checklist and automated audit methodology skill. Wcag Checker is an agent skill from revfactory/harness-100.2 accessibility verification checklist and automated audit methodology skill.
When should I use Wcag Checker?
Wcag Checker fits situations like: requests like verify accessibility; check contrast ratio; keyboard accessibility; screen reader test.
How do I install Wcag Checker in Claude Code?
Run `npx skills add revfactory/harness-100 --skill wcag-checker -a claude-code`. Or copy the skill folder (en/36-design-system/.claude/skills/wcag-checker in revfactory/harness-100) into .claude/skills/wcag-checker in your project. Claude Code loads it when a task matches its description.
How do I install Wcag Checker in Codex?
Run `npx skills add revfactory/harness-100 --skill wcag-checker -a codex`. Or copy the skill folder (en/36-design-system/.claude/skills/wcag-checker in revfactory/harness-100) into .agents/skills/wcag-checker in your project. Codex loads it when a task matches its description.
Can I use Wcag Checker in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add revfactory/harness-100 --skill wcag-checker -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/wcag-checker, .gemini/skills/wcag-checker, .github/skills/wcag-checker and .opencode/skills/wcag-checker in your project.
What does Wcag Checker need to run?
SKILL.md names no scripts, command-line tools or credentials: Wcag Checker is instructions for the agent only.
Does Wcag Checker access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Wcag Checker safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Wcag Checker use?
Wcag Checker is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Wcag Checker use?
About 1.4k tokens (SKILL.md is roughly 5.6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Wcag Checker?
Skills that share tags, products or a category with Wcag Checker: Web Interface Guidelines Reviewer (vercel-labs/openreview, 1.7k stars), Accessibility Review (markmead/hyperui, 12k stars), Web Animation Design (baptisteArno/typebot.io, 11k stars) and Accessibility Fixer (ibelick/ui-skills, 9.5k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Wcag Checker?
revfactory (a GitHub user) maintains it in revfactory/harness-100, which has 1,295 GitHub stars. The repository holds 464 skills in this directory. The repository was last updated on March 22, 2026.
Source: revfactory/harness-100 on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.