A11y Audit

Audit code for WCAG 2.1 AA compliance using static analysis. Identify issues, prescribe safe fixes, enforce "no ARIA is better than bad ARIA."

Scope: a single file or a directory of components. This skill does NOT audit page-level flow (see /a11y-flow-audit) and does NOT produce remediation plans, staffing estimates, or customer-facing commitments (see /a11y-remediate).

How to use this skill

1. Run the detection spine (below) before reading the code in depth.
2. Emit the mandatory calibration one-liner so miscalibration surfaces early.
3. Read the relevant reference leaves per the routing table.
4. Write the audit following references/output-format.md layer by layer.
5. Run the Safety Self-check before emitting any Fix field.

Detection spine

Run once per audit. Cache mentally for the session.

Step 1 — Framework

Inspect the target file and its imports. First match wins.

• import from 'react' → React
• import from 'lit' / customElements.define / extends LitElement → Lit
• .svelte extension or import from 'svelte' → Svelte
• .vue extension or import from 'vue' → Vue
• Plain .html with no framework imports → Vanilla HTML/JS
• Other / hybrid → name it plainly.

Step 2 — Product type

• package.json with engines.vscode → VS Code extension (webview content is fully your responsibility).
• Electron / Tauri dependencies → Desktop app.
• react-dom / vue/server-renderer + routing libs → Web app.
• Package is exported as a library (main / exports / published to npm with no runnable entry) → Shared component library.
• Ambiguous → pick the best match and state it.

Step 3 — Shared-library detection

If the target is in a package that is imported by multiple consumers (OR if the repo name suggests "components", "ui-kit", "shared-web-components", etc.), flag Shared: yes, {library name}. Shared status escalates Rule 8 (visual-regression) concern for semantic-element swaps.

Step 4 — Locale system

Grep for locale/translation files under directories matching locale|i18n|lang|translations. Count the number of locale file candidates (*.json, *.yaml, *.po, *.ftl). If multiple locales exist AND a Fix requires a new translation key, note that key additions touch locale files — flag effort accordingly even if the ARIA change is small.

Step 5 — Test presence

Check for adjacent *.test.*, *.spec.*, or __snapshots__/ — if present, note which issues involve DOM structure changes that may break tests. Don't audit the tests; just flag the intersection.

Mandatory calibration one-liner

Before writing the audit body, emit this exact one-liner (replacing the placeholders):

Framework: {X}. Product: {Y}. Shared lib: {yes/no[, library name]}. Locale files: {count}. Tests present: {yes, {paths} | no}.

This is non-negotiable. It surfaces miscalibration before it corrupts output. A reader can interrupt and correct.

Load-bearing rules (always apply)

Full rules live in references/safety-rules.md. Read them before emitting any Fix. Compressed list for quick scan:

1. No orphan ARIA roles — composite patterns (grid/menu/listbox/tree/tabs/radiogroup/combobox/dialog) must ship complete. Never propose a single role from the pattern table standalone. (→ aria-patterns.md, safety-rules.md)
2. No tabIndex without keyboard handlers — focusable-but-inert is a new bug. (→ safety-rules.md)
3. No container role without child roles — role="grid" without rows, etc. Bundle via Issue Groups. (→ safety-rules.md)
4. No unverified symbols in code diffs — if a Fix's code contains [unverified: X], Fix Confidence MUST be Low with a Design Decision block. Never paste a class/key/helper the dev can't find. (→ safety-rules.md)
5. No invented ARIA — only attributes in the WAI-ARIA spec. No aria-valid-style fabrications. (→ safety-rules.md)
6. No aria-label as substitute for visible text — visible text (with sr-only backup) is preferred. (→ safety-rules.md)
7. No predictive claims about tools or AT — "axe will flag this", "NVDA will announce X" — banned. Cite the WCAG criterion; don't predict runtime output. (→ safety-rules.md)
8. Semantic-element swaps in shared components must address visual regression — bare <button> replacing <span> without a CSS reset plan is a banned fix. (→ shared-component-rules.md)
9. Fixes depending on an imported wrapper must analyze that wrapper — open the wrapper, summarize its behavior. Third-party black box → Risk: High. (→ shared-component-rules.md)
10. No editing artifacts in the output — phrases like "Actually...", "Re-graded:", "On reflection" are banned. If you change your mind, rewrite the section cleanly. (→ safety-rules.md)
11. No semantic-verification handoff in Medium/High confidence fixes — if the Fix tells the dev to "verify runtime side effects" or "grep consumer products," the Fix is not ready. Either do the verification in the audit, or drop Confidence to Low with a Design Decision block. (→ safety-rules.md)

When to load which reference

If a task spans multiple situations (typical — most audits involve multiple patterns), load all matching references.

What to check

Analyze the code against these categories, mapped to WCAG 2.1 AA criteria. See references/wcag-criteria.md for URL and plain-English impact per criterion.

Perceivable

• Images and icons (1.1.1) — <img> alt attributes; icon-only controls need aria-label or visually-hidden text; decorative images need alt="" or aria-hidden="true".
• Semantic structure (1.3.1) — heading hierarchy, semantic elements (<nav>, <main>, <aside>, <section>), list markup, table markup with headers. Flag <div>/<span> used for interactive elements without ARIA roles.
• Meaningful sequence (1.3.2) — DOM order matches visual order; CSS order / grid placement should not break reading flow.
• Color-only information (1.4.1) — status indicated only by color with no icon/text alternative.
• Contrast (1.4.3, 1.4.11) — you cannot compute contrast from code alone. Flag suspicious patterns; recommend runtime verification.
• Text resizing and reflow (1.4.4, 1.4.10) — fixed pixel widths on text containers, fixed heights that clip, overflow: hidden on text containers.
• Hover/focus content (1.4.13) — tooltips/popovers: dismissable? hoverable? persistent?

Operable

• Keyboard (2.1.1, 2.1.2) — onClick without onKeyDown on non-interactive elements; positive tabIndex values (anti-pattern); keyboard trap patterns.
• Character key shortcuts (2.1.4) — single-character shortcuts without modifier keys must be configurable.
• Skip mechanisms (2.4.1) — skip links / landmarks for pages with navigation.
• Page titles (2.4.2) — <title> / document.title / equivalent.
• Focus order (2.4.3) — positive tabIndex; CSS reordering that breaks DOM order.
• Link purpose (2.4.4) — "click here", "more", "read more" without aria-label or surrounding context.
• Focus visibility (2.4.7) — outline: none / outline: 0 without replacement; :focus removed without :focus-visible alternative.
• Target size (2.5.3) — click targets hardcoded below 24x24px.

Understandable

• Language (3.1.1) — lang attribute on root.
• Predictable (3.2.1, 3.2.2) — onChange that triggers navigation; onFocus that modifies the page.
• Error handling (3.3.1-3.3.3) — forms: associated labels, error messages linked via aria-describedby or aria-errormessage, required field indication.

Robust

• ARIA usage (4.1.2) — correct ARIA roles/states/properties; roles without required attributes (e.g., role="checkbox" without aria-checked); conflicting attributes; custom interactive elements without ARIA roles.
• Status messages (4.1.3) — dynamic content updates need aria-live or equivalent.

Severity calibration

Full definitions and decision guide in references/output-format.md. Quick reference:

Apply these adjustments after the initial grade:

• Can user complete the workflow? No → P0/P1. Yes → P2/P3.
• Core vs peripheral workflow → bump up / down one.
• Reasonable workaround exists → bump down one.
• Affects multiple views systemically → bump up one.

Self-check before emitting any Fix

Answer these before writing each Fix field (full text in safety-rules.md):

1. Does this fix complete a pattern, or only part of one? (Rules 1, 3)
2. Does this fix create a focusable-but-inert element? (Rule 2)
3. Does this fix reference any unverified symbol? (Rule 4)
4. Is every ARIA attribute in the WAI-ARIA spec? (Rule 5)
5. Am I bundling everything that must ship together? (Rules 1, 3)
6. Would this fix hide information from sighted users? (Rule 6)
7. Am I making any predictive claim about tool or AT output? (Rule 7)
8. If semantic swap in a shared component, have I addressed visual-regression risk? (Rule 8)
9. If this fix depends on an imported wrapper, have I analyzed that wrapper? (Rule 9)
10. Does my draft contain any editing-artifact phrases (Actually, Re-graded, On reflection)? (Rule 10)
11. Am I handing off semantic verification inside a Medium/High confidence fix? (Rule 11)

If any answer is "no" or "not sure," either bundle the missing piece, escalate Effort/Risk to L / High, or convert the Fix to a Design Decision block per output-format.md.

Pre-finalize pass (MANDATORY — before writing the report to disk)

The per-Fix self-check catches issues as you write them. This pre-finalize pass catches what the per-Fix check missed. It is NOT optional. Run the three shared scans in references/shared-discipline.md (full procedures there) over the completed draft:

1. Unverified symbols inside code the dev would copy — enforces Rule 4's sub-rule
2. Editing artifacts — enforces Rule 10
3. Fix Confidence / Design Decision coherence — enforces Rule 11

If any scan finds something, fix it before writing the file. Do not write a draft-with-known-issues and leave them for the reader to catch. After all three scans pass, emit the calibration one-liner (detection spine) and then the full report.

Ambiguity handling

Never fabricate. When you don't know, say so in the output, don't guess silently.

Thoroughness

Audit every file you read. Do not skip issues because a file has "enough" findings already. Common categories easy to overlook:

• Heading hierarchy problems
• Focus-indicator suppression without replacement
• CSS visual reordering that breaks DOM order
• Component APIs that override consumer-set attributes
• Disabled state handling across button-role vs link-role variants

If you read a shared component, audit it fully — not just the parts exercised by the current view. A shared component may have code paths that affect other consumers.

Confirmed issues vs needs-verification — strict separation

Per references/shared-discipline.md: confirmed issues (defect visible directly in the code) go in the issue table; needs-verification items (a browser is required to confirm — contrast ratios, runtime focus behavior) go ONLY in "Items Requiring Runtime Tooling."

Quick reference to output format

Full templates in references/output-format.md. In brief, every audit emits:

• Layer 1 — Summary: header block + scope boundary + extrapolation warning + customer one-liner + notation legend + plain-English status + totals + fix-confidence breakdown + rough sizing + WCAG criteria affected + High-Leverage Fixes + Top Patterns + Issue Groups + Safely Shippable Now + Verification Playbook + Items Requiring Runtime Tooling.
• Layer 2 — All Issues table: one row per issue with severity, file, line, description, effort/risk, fix confidence, WCAG link.
• Layer 3 — Detailed Findings: one section per issue with WCAG criterion link, effort/risk, fix confidence, why-risk (if Med/High), user-impact statement, code, fix (or Design Decision block).