The full upstream README, mirrored here for reference. Install config, tool schemas, adoption signals, and an original overview live on the Aether WCAG Scanner listing page.
A Claude Code plugin that finds WCAG 2.1 AA accessibility violations and returns ready-to-apply fixes — not just a list of problems.
It drives a real browser (Playwright + axe-core) across desktop, tablet, and mobile viewports, then pairs each violation with a concrete fix: corrected HTML, the relevant WCAG success criteria, and technique code examples.
An AI coding agent working from markup alone has to infer what a page does. Aether runs the page in a real browser, measures it with axe-core, and grounds every suggested fix in the WCAG spec, so the agent is working from measurements rather than inference.
| Coding agent alone | Aether, offline | Aether, with API key | |
|---|---|---|---|
| How it looks at the page | Reads the HTML it is given | Renders the page in Chromium at desktop, tablet and mobile widths and runs axe-core | Same |
| What it can measure | Structure visible in the markup | What axe measures on the rendered page: contrast, accessible names, ARIA usage, focusable regions, landmarks | Same |
| Fix suggestions | From the model's general knowledge | Deterministic templates for the common rules | Templates first, then WCAG-corpus examples, then a model; every cited technique passes a grounding check |
| How fixes are checked | Not checked unless you set that up | axe re-run on the fixed element; reports what cleared and what regressed | Same |
| What each fix cites | Whatever the model recalls | The axe rule and its severity | The WCAG success criteria and techniques, with rejected candidates shown |
| Network | Depends on the agent | None; runs entirely on your machine | Fix requests go to the hosted engine; falls back to offline templates when it is unreachable |
Once the official Claude Code marketplace listing is live, you can also install it directly from there.
The install prompts for your Allchemy Labs API key; paste the key you got from beta.allchemylabs.ai. To set or change it later:
The first start installs the plugin's dependencies (about a minute) and the
first scan downloads Chromium for Playwright. If /mcp shows the server as not
connected right after install, wait a moment and run /reload-plugins.
The scanner itself runs locally and works without a key: you get template
fixes for every violation. The key adds corpus-grounded fixes from the hosted
insights engine. Set it via the prompt above, or put ALLCHEMY_API_KEY=<key>
in the .env of the project you are scanning.
The same server is published to npm and the MCP Registry as
@allchemylabs/aether-wcag-scanner. Any MCP client that speaks stdio can run it:
The first scan downloads Chromium once (about 150 MB). Without ALLCHEMY_API_KEY
the scanner still runs fully offline and returns template fixes.
Claude Code gets the /wcag-scan skill, which drives the scan → review → fix → verify
loop. Other agents only see the tool descriptions and the instructions the server sends at
connect time, so for the same behaviour copy AGENTS.md into your project
(Codex reads it natively; Cursor and Windsurf accept it as a rules file). Without it an agent
may fetch the page HTML and guess instead of running the browser scan.
| Tool | What it does |
|---|---|
aether_scan_and_fix | Recommended. Scan a URL — or a single-page app across routes via the spa block — and return violations with fixes, each verified on the real browser, in one call. Set maxFixes: 0 for a fast scan-only pass. |
aether_get_fix | Get a fix for one specific violation (verified on the real browser). Omit html to instead get a rule-level explanation — WCAG success criteria and technique examples. |
aether_verify_fix | Deterministically verify a fix with real Playwright + axe — re-scan a URL or diff original vs fixed HTML. Reports whether the target cleared, any new regressions, and the net compliance delta. |
aether_check_html | Analyze an HTML snippet for issues — no live URL or browser needed. |
aether_submit_feedback | Rate a fix (useful / not useful) so the guidance engine keeps improving; your correction helps seed better fixes. |
Just ask Claude naturally, e.g. "check localhost:3000 for accessibility issues and fix them" — it will pick the right tool.
/wcag-scan skillRun /wcag-scan <url> for a guided workflow: scan → review violations → apply
fixes → re-scan to verify → summarize. The skill orchestrates the tools above
and edits your files in place.
Pass a spa block to aether_scan_and_fix instead of url:
entryUrl — where the app boots. Routes are discovered by crawling client-side links
unless you list them in routes: [{ "path": "/settings", "name": "Settings" }].framework — angular, react, vue, or omit to auto-detect.maxRoutes — cap on discovered routes.Navigation is client-side (the browser context and app state are kept between routes),
and readiness is decided by a layered stability cascade — DOM quiet, framework hooks such
as Angular testability, pending-request drain — never by Playwright's networkidle,
which deadlocks on apps with long-polling or websockets. A config that sets
networkIdle is rejected for that reason.
Aether is an accessibility analysis and guidance tool. Using the platform does not, by itself, make your website, application, or digital service conformant with WCAG, the ADA (including Title II), the European Accessibility Act, Section 508, EN 301 549, or any other accessibility law or standard.
Automated scans detect only a subset of accessibility barriers. A "zero issues" result means the scanner did not flag anything in its detection range — not that the property is legally compliant.
You remain responsible for:
Aether does not provide legal advice and does not replace an accessibility audit or a VPAT/ACR prepared by a qualified auditor.
MIT for the client (this plugin). The hosted insights engine and related
Allchemy Labs services are proprietary — see LICENSE and NOTICE.