accessibility

You make UI usable by people with disabilities — blind and low-vision users with screen readers and magnification, keyboard and switch users, people with motor, hearing, vestibular, and cognitive disabilities. The target is WCAG 2.2 level AA, applied through each platform's own accessibility APIs.

1. Pick the Mode

Decide from the request; do not ask.

• Build mode — the task creates or changes UI. Apply the rules as constraints while writing the code: semantic elements, labels, focus, contrast, scaling. Mention a rule only when it changed a decision, in one line. No report.
• Audit mode — the user asks to review, audit, or check accessibility, or prepares a release. Produce the report in Step 4.

2. Detect the Platform

Read the manifest as prose and load only the matching guide:

Platform	Detected by	Load
Web	package.json with a web framework, or HTML templates	references/web.md
React Native / Expo	package.json with expo or react-native	references/cross-platform.md
Apple platforms	*.xcodeproj, Package.swift with an app target	references/apple.md
Android (Compose)	build.gradle(.kts) with Compose	references/android.md

React Native/Expo: add references/apple.md or references/android.md when behaviour differs per OS (screen reader focus, announcements, system settings). Expo web output also loads references/web.md. Flutter and other stacks: references/cross-platform.md.

3. Rules

Each rule file has When building constraints, When auditing checks, and the WCAG success criteria it covers. Read a rule when the UI in front of you involves what its "Applies to" column names.

Rule	Impact	Applies to	File
Semantics, names, and roles	CRITICAL	every interactive element, custom controls, headings	rules/semantics.md
Keyboard and focus	CRITICAL	web, iPad/Mac/Android with keyboards, modals, menus	rules/keyboard-focus.md
Text alternatives	HIGH	images, icons, icon buttons, charts, maps	rules/text-alternatives.md
Contrast and colour	HIGH	text, icons, borders of controls, status colours	rules/contrast-color.md
Text scaling and reflow	HIGH	all text, layouts, fixed-height containers	rules/text-scaling.md
Forms and errors	HIGH	inputs, validation, sign-in, multi-step flows	rules/forms.md
Touch targets and gestures	HIGH	buttons, icons, drag, swipe, multi-finger gestures	rules/targets-gestures.md
Motion, flashing, and time	HIGH	animation, carousels, autoplay, timeouts	rules/motion-time.md
Announcements and status	MEDIUM	toasts, loading, live updates, async results	rules/announcements.md
Media	MEDIUM	video, audio, podcasts, animated explainers	rules/media.md

4. Audit Mode

1. Scope: the files or screens named; otherwise every user-facing screen. In Claude Code, hand a whole-app or multi-screen audit to the a11y-audit agent when it is available, so the files it reads stay out of the main context.
2. Run the platform's automated checks first (listed in each platform guide) — then review by hand. Automated tools find only part of WCAG failures; most problems with names, focus order, and meaning need a person (or you, reading the code)
3. Check each screen against the rules whose "Applies to" matches it
4. Report, grouped by impact (CRITICAL first):

### CRITICAL — Semantics
- app/settings.tsx:58 — icon-only "trash" button has no accessible name → accessibilityLabel="Delete project" (WCAG 4.1.2)

End with the counts per impact and this limit, stated plainly: a code review cannot prove accessibility. Recommend testing the primary flows with the platform screen reader (VoiceOver, TalkBack, NVDA/JAWS), keyboard only, and the largest text size — and, where possible, with disabled users.

Fix nothing in audit mode unless asked; when asked, fix in impact order.

Why It Matters

Around one in six people live with a significant disability (WHO), and accessible design helps everyone — captions in a noisy room, large targets on a moving train. It is also law in many markets: the European Accessibility Act applies to many digital products and services sold in the EU, and US courts and regulators apply the ADA to websites and apps. Both reference WCAG.

Boundaries

• UX psychology (cognitive load, decisions, persuasion) belongs to ux-psychology; this skill covers access. They overlap at target size, colour-only signals, and clear errors — follow whichever is stricter.
• Legal compliance depends on jurisdiction and contract; this skill names the standards, it is not legal advice.