cognitive-accessibility（认知可达性）

Skill: Cognitive Accessibility

Domain: Cognitive, learning, and neurological accessibility WCAG scope: WCAG 2.2 AA + key AAA, COGA W3C guidance Agents that use this skill: cognitive-accessibility, web-accessibility-wizard, accessibility-lead, forms-specialist

Purpose

This skill provides reference tables, scoring formulas, and evaluation patterns for cognitive accessibility review. It covers:

• WCAG 2.2 success criteria with cognitive accessibility relevance
• COGA (Cognitive Accessibility) W3C guidance mapping
• Plain language analysis techniques
• Reading level computation
• Authentication pattern analysis (3.3.8 / 3.3.9)
• Redundant entry detection (3.3.7)
• Timeout and session management analysis

WCAG 2.2 Cognitive Accessibility Criteria Reference

Level A

Level AA

Level AAA (Advisory - Review and Report)

Authentication Pattern Analysis (3.3.8 / 3.3.9)

Failing Patterns

Passing Patterns

Redundant Entry Patterns (3.3.7)

Detection Checklist

In multi-step forms or wizards:

1. Map all input fields across all steps
2. Flag any field that requests information already collected in an earlier step
3. Exception: security confirmation (password confirm) and data that can become stale (current vs. new address)

Common Violations

Plain Language Analysis

Sentence Analysis

Evaluate all instructional text, error messages, button labels, and tooltip copy.

Error Message Quality Rubric

Score each error message 0-3 on each dimension:

Minimum score to pass: 2 on Identification, 1 on Solution.

Error Message Examples

Reading Level Computation

Flesch-Kincaid Grade Level Formula

$$GL = 0.39 \times \frac{W}{S} + 11.8 \times \frac{Sy}{W} - 15.59$$

Where:

• $W$ = total words
• $S$ = total sentences
• $Sy$ = total syllables

Syllable counting rules:

• Count each vowel cluster (a, e, i, o, u) as one syllable
• Subtract one syllable for silent trailing *e* ("made" = 1, "make" = 1)
• Each word has at least 1 syllable

Grade Level Targets

Quick-Estimate Method (when full computation is impractical)

Flag content for reading level review when:

• Any single sentence exceeds 35 words
• More than 30% of words exceed 3 syllables in a paragraph
• 3 or more Latin abbreviations in a single page ("i.e.", "e.g.", "et al.", "viz.")

Timeout Warning Requirements (2.2.1)

Detection Pattern

1. Identify any page or application state with session persistence (authenticated areas, multi-step forms with temporary state)
2. Check for: activity monitoring, session expiry timers, auto-logout functionality
3. Verify warning mechanism exists when found

Compliant Implementation Pattern

// PASS: Session warning with extension option
const SESSION_TIMEOUT_MS = 15 * 60 * 1000; // 15 minutes
const WARNING_BEFORE_MS = 2 * 60 * 1000;   // Warn 2 minutes before

let warningShown = false;

sessionTimer = setTimeout(() => {
  if (!warningShown) {
    warningShown = true;
    showSessionWarning({
      message: "Your session will expire in 2 minutes due to inactivity.",
      extendLabel: "Stay signed in",
      logoutLabel: "Sign out now",
      onExtend: () => { resetTimer(); warningShown = false; },
      onLogout: () => endSession()
    });
  }
}, SESSION_TIMEOUT_MS - WARNING_BEFORE_MS);

ARIA for Session Warning

<div role="alertdialog" aria-modal="true" aria-labelledby="session-title" aria-describedby="session-desc">
  <h2 id="session-title">Session expiring</h2>
  <p id="session-desc">Your session will expire in <span id="session-countdown">2:00</span> minutes.</p>
  <button type="button" id="extend-btn" autofocus>Stay signed in</button>
  <button type="button">Sign out</button>
</div>

COGA Guidance Mapping

Making Content Usable - Key Objectives

From the W3C COGA "Making Content Usable for People with Cognitive and Learning Disabilities" guidance:

Severity Assessment for COGA Findings

Integration Notes

When Used by web-accessibility-wizard

The wizard invokes cognitive-accessibility as part of Phase 3 (Forms and Input) and Phase 5 (Dynamic Content). Specifically:

• Phase 3: delegates 3.3.7 and 3.3.8 detection + error message quality to this skill
• Phase 5: delegates timeout warning detection to this skill

When Used Standalone

cognitive-accessibility agent loads this skill and applies the full Phase 2 + Phase 3 assessment independently. It accepts page URLs, component files, or plain text content blocks.

Handoffs from this Skill

• Form validation specifics -> forms-specialist
• ARIA state for error announcements -> aria-specialist
• Live region for timeout warnings -> live-region-controller
• WCAG criterion explanations -> wcag-guide