536 lines
13 KiB
Markdown
536 lines
13 KiB
Markdown
# Cremote ADA/WCAG Accessibility Testing Guide
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## Overview
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Cremote provides comprehensive automated accessibility testing tools that cover approximately **70% of WCAG 2.1 Level AA criteria**. This guide documents all accessibility testing capabilities, their usage, and best practices for conducting ADA compliance audits.
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## Table of Contents
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1. [Quick Start](#quick-start)
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2. [Available Tools](#available-tools)
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3. [WCAG Coverage](#wcag-coverage)
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4. [Testing Workflows](#testing-workflows)
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5. [Tool Reference](#tool-reference)
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6. [Best Practices](#best-practices)
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7. [Limitations](#limitations)
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---
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## Quick Start
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### Basic Accessibility Audit
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```bash
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# 1. Navigate to page
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cremote navigate --url https://example.com
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# 2. Run axe-core automated tests (covers ~57% of WCAG 2.1 AA)
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cremote inject-axe
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cremote run-axe --run-only wcag2a,wcag2aa
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# 3. Check color contrast (WCAG 1.4.3, 1.4.6)
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cremote contrast-check
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# 4. Test keyboard navigation (WCAG 2.1.1, 2.4.7)
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cremote keyboard-test
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# 5. Test zoom functionality (WCAG 1.4.4)
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cremote zoom-test --zoom-levels 1.0,2.0,4.0
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# 6. Test responsive reflow (WCAG 1.4.10)
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cremote reflow-test --widths 320,1280
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```
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---
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## Available Tools
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### 1. **web_inject_axe_cremotemcp** - Axe-Core Integration
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Injects the industry-standard axe-core accessibility testing library.
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**WCAG Coverage:** ~57% of WCAG 2.1 Level AA criteria
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**Usage:**
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```json
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{
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"tool": "web_inject_axe_cremotemcp",
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"arguments": {
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"tab": "optional-tab-id",
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"axe_version": "4.8.0",
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"timeout": 30
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}
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}
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```
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### 2. **web_run_axe_cremotemcp** - Run Axe Tests
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Executes axe-core accessibility tests with configurable options.
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**WCAG Coverage:** Comprehensive automated testing including:
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- 1.1.1 Non-text Content
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- 1.3.1 Info and Relationships
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- 1.4.1 Use of Color
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- 2.1.1 Keyboard
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- 2.4.1 Bypass Blocks
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- 3.1.1 Language of Page
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- 4.1.1 Parsing
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- 4.1.2 Name, Role, Value
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**Usage:**
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```json
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{
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"tool": "web_run_axe_cremotemcp",
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"arguments": {
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"tab": "optional-tab-id",
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"run_only": ["wcag2a", "wcag2aa", "wcag21aa"],
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"rules": {
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"color-contrast": {"enabled": true}
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},
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"timeout": 30
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}
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}
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```
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**Output:**
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- Violations with severity, impact, and remediation guidance
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- Passes (successful checks)
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- Incomplete (manual review needed)
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- Inapplicable rules
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### 3. **web_contrast_check_cremotemcp** - Color Contrast Testing
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Calculates WCAG-compliant contrast ratios for all text elements.
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**WCAG Coverage:**
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- 1.4.3 Contrast (Minimum) - Level AA
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- 1.4.6 Contrast (Enhanced) - Level AAA
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**Usage:**
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```json
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{
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"tool": "web_contrast_check_cremotemcp",
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"arguments": {
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"tab": "optional-tab-id",
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"selector": "body",
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"timeout": 10
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}
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}
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```
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**Features:**
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- Uses official WCAG 2.1 relative luminance formula
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- Traverses parent elements to find effective backgrounds
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- Detects large text (18pt+ or 14pt bold+) for different thresholds
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- Returns AA (4.5:1 normal, 3:1 large) and AAA (7:1 normal, 4.5:1 large) compliance
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**Output Example:**
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```
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Color Contrast Check Results:
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Summary:
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Total Elements Checked: 45
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WCAG AA Compliance:
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Passed: 38
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Failed: 7
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WCAG AAA Compliance:
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Passed: 25
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Failed: 20
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WCAG AA Violations:
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- p:nth-of-type(3): 3.2:1 (required: 4.5:1)
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Text: This text has insufficient contrast
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Colors: rgb(128, 128, 128) on rgb(255, 255, 255)
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```
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### 4. **web_keyboard_test_cremotemcp** - Keyboard Navigation Testing
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Tests keyboard accessibility and focus management.
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**WCAG Coverage:**
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- 2.1.1 Keyboard - Level A
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- 2.4.7 Focus Visible - Level AA
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**Usage:**
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```json
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{
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"tool": "web_keyboard_test_cremotemcp",
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"arguments": {
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"tab": "optional-tab-id",
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"timeout": 10
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}
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}
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```
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**Features:**
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- Identifies 11 types of interactive elements (links, buttons, inputs, ARIA roles)
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- Tests focusability of each element
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- Validates visible focus indicators by comparing focused/blurred styles
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- Detects keyboard traps
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- Returns detailed tab order
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**Output Example:**
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```
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Keyboard Navigation Test Results:
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Summary:
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Total Interactive Elements: 38
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Focusable: 32
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Not Focusable: 4
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Missing Focus Indicator: 6
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Keyboard Traps Detected: 0
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High Severity Issues (10):
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- no_focus_indicator: Interactive element lacks visible focus indicator
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Element: button.submit-btn
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- not_focusable: Interactive element is not keyboard focusable
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Element: div[role="button"]
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Tab Order (first 5 elements):
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1. a.logo [a] Home - Focus: ✓
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2. a.nav-link [a] About - Focus: ✓
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3. button.menu [button] Menu - Focus: ✗
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```
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### 5. **web_zoom_test_cremotemcp** - Zoom Testing
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Tests page functionality at different zoom levels.
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**WCAG Coverage:**
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- 1.4.4 Resize Text - Level AA
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**Usage:**
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```json
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{
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"tool": "web_zoom_test_cremotemcp",
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"arguments": {
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"tab": "optional-tab-id",
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"zoom_levels": [1.0, 2.0, 4.0],
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"timeout": 10
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}
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}
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```
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**Features:**
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- Uses Chrome DevTools Protocol Emulation.setDeviceMetricsOverride
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- Tests at configurable zoom levels (defaults: 100%, 200%, 400%)
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- Checks for horizontal scrolling (WCAG 1.4.10 violation)
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- Validates text readability (minimum 9px font size)
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- Counts overflowing elements
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- Automatically resets viewport after testing
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**Output Example:**
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```
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Zoom 200% ✓ PASS:
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Viewport: 1280x720
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Content: 1280x1450
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Horizontal Scroll: false
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Overflowing Elements: 0
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Text Readable: true
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Zoom 400% ✗ FAIL:
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Viewport: 1280x720
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Content: 1350x2100
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Horizontal Scroll: true
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Overflowing Elements: 3
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Text Readable: true
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```
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### 6. **web_reflow_test_cremotemcp** - Responsive Reflow Testing
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Tests responsive design at WCAG breakpoints.
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**WCAG Coverage:**
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- 1.4.10 Reflow - Level AA
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**Usage:**
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```json
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{
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"tool": "web_reflow_test_cremotemcp",
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"arguments": {
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"tab": "optional-tab-id",
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"widths": [320, 1280],
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"timeout": 10
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}
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}
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```
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**Features:**
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- Tests at WCAG 1.4.10 breakpoints (defaults: 320px, 1280px)
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- Resizes viewport using Emulation.setDeviceMetricsOverride
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- Detects horizontal scrolling violations
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- Verifies responsive layout (content width ≤ viewport width)
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- Counts overflowing elements
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- Automatically resets viewport after testing
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**Output Example:**
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```
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320px Width ✓ PASS:
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Viewport: 320x568
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Content: 320x1200
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Horizontal Scroll: false
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Responsive Layout: true
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Overflowing Elements: 0
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1280px Width ✓ PASS:
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Viewport: 1280x720
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Content: 1280x900
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Horizontal Scroll: false
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Responsive Layout: true
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Overflowing Elements: 0
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```
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### 7. **console_command_cremotemcp** (Enhanced) - Library Injection
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Execute JavaScript with optional library injection.
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**Usage:**
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```json
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{
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"tool": "console_command_cremotemcp",
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"arguments": {
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"command": "axe.run()",
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"inject_library": "axe",
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"tab": "optional-tab-id",
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"timeout": 5
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}
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}
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```
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**Supported Libraries:**
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- `axe` / `axe-core` - Axe-core accessibility testing
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- `jquery` - jQuery library
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- `lodash` - Lodash utility library
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- `moment` - Moment.js date library
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- `underscore` - Underscore.js utility library
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- Or any custom URL
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### 8. **web_screenshot_cremotemcp** (Enhanced) - Accessibility Screenshots
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Capture screenshots with zoom and viewport control.
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**Usage:**
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```json
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{
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"tool": "web_screenshot_cremotemcp",
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"arguments": {
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"output": "/path/to/screenshot.png",
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"zoom_level": 2.0,
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"width": 320,
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"height": 568,
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"full_page": false,
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"timeout": 5
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}
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}
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```
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**Use Cases:**
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- Document zoom level issues
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- Capture responsive breakpoint layouts
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- Visual regression testing for accessibility fixes
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### 9. **get_accessibility_tree_cremotemcp** (Enhanced) - Accessibility Tree with Contrast
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Retrieve accessibility tree with optional contrast annotations.
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**Usage:**
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```json
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{
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"tool": "get_accessibility_tree_cremotemcp",
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"arguments": {
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"tab": "optional-tab-id",
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"depth": 5,
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"include_contrast": true,
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"timeout": 5
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}
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}
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```
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**Features:**
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- Full Chrome accessibility tree
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- Optional contrast check availability annotation
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- Depth limiting for large pages
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- Includes roles, names, descriptions, properties
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---
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## WCAG Coverage
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### Automated Testing Coverage (~70% of WCAG 2.1 Level AA)
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| WCAG Criterion | Level | Tool(s) | Coverage |
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|----------------|-------|---------|----------|
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| 1.1.1 Non-text Content | A | axe-core | Partial |
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| 1.3.1 Info and Relationships | A | axe-core | Partial |
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| 1.4.1 Use of Color | A | axe-core | Partial |
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| 1.4.3 Contrast (Minimum) | AA | contrast-check, axe-core | Full |
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| 1.4.4 Resize Text | AA | zoom-test | Full |
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| 1.4.6 Contrast (Enhanced) | AAA | contrast-check | Full |
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| 1.4.10 Reflow | AA | reflow-test | Full |
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| 2.1.1 Keyboard | A | keyboard-test, axe-core | Partial |
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| 2.4.1 Bypass Blocks | A | axe-core | Full |
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| 2.4.7 Focus Visible | AA | keyboard-test | Full |
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| 3.1.1 Language of Page | A | axe-core | Full |
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| 4.1.1 Parsing | A | axe-core | Full |
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| 4.1.2 Name, Role, Value | A | axe-core, a11y-tree | Partial |
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### Manual Testing Required (~30%)
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- 1.2.x Audio/Video (captions, audio descriptions)
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- 1.4.2 Audio Control
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- 2.2.x Timing (pause, stop, hide)
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- 2.3.x Seizures (flashing content)
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- 2.4.x Navigation (page titles, link purpose, headings)
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- 3.2.x Predictable (on focus, on input)
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- 3.3.x Input Assistance (error identification, labels)
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---
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## Testing Workflows
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### Complete ADA Audit Workflow
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```bash
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# 1. Initial Setup
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cremote navigate --url https://example.com
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cremote screenshot --output baseline.png
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# 2. Automated Testing (Axe-Core)
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cremote inject-axe
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cremote run-axe --run-only wcag2a,wcag2aa,wcag21aa > axe-results.json
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# 3. Specialized Tests
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cremote contrast-check > contrast-results.txt
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cremote keyboard-test > keyboard-results.txt
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cremote zoom-test --zoom-levels 1.0,2.0,4.0 > zoom-results.txt
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cremote reflow-test --widths 320,1280 > reflow-results.txt
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# 4. Visual Documentation
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cremote screenshot --output zoom-200.png --zoom-level 2.0
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cremote screenshot --output mobile-320.png --width 320 --height 568
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cremote screenshot --output desktop-1280.png --width 1280 --height 720
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# 5. Accessibility Tree Analysis
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cremote get-accessibility-tree --include-contrast true > a11y-tree.json
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```
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### Quick Compliance Check
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```bash
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# Run all core tests in sequence
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cremote inject-axe && \
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cremote run-axe && \
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cremote contrast-check && \
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cremote keyboard-test && \
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cremote zoom-test && \
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cremote reflow-test
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```
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---
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## Best Practices
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### 1. Test Early and Often
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- Run automated tests during development
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- Integrate into CI/CD pipelines
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- Test on every significant UI change
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### 2. Combine Automated and Manual Testing
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- Use automated tools for ~70% coverage
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- Manually verify complex interactions
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- Test with actual assistive technologies
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### 3. Test Multiple Breakpoints
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```bash
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# Test common device sizes
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cremote reflow-test --widths 320,375,768,1024,1280,1920
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```
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### 4. Document Visual Issues
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```bash
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# Capture evidence of issues
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cremote screenshot --output issue-contrast.png
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cremote screenshot --output issue-zoom-400.png --zoom-level 4.0
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```
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### 5. Prioritize Violations
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- **Critical:** Axe violations with "critical" or "serious" impact
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- **High:** Contrast failures, keyboard traps, missing focus indicators
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- **Medium:** Zoom/reflow issues, incomplete axe checks
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- **Low:** Best practice recommendations
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---
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## Limitations
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### What These Tools Cannot Test
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1. **Semantic Meaning** - Tools can detect missing alt text but not if it's meaningful
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2. **Cognitive Load** - Cannot assess if content is easy to understand
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3. **Timing** - Cannot fully test time-based media or auto-updating content
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4. **Context** - Cannot determine if link text makes sense out of context
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5. **User Experience** - Cannot replace testing with real users and assistive technologies
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### Known Issues
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- **Contrast Detection:** May not accurately detect contrast on complex backgrounds (gradients, images)
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- **Keyboard Traps:** Detection is heuristic-based and may miss complex traps
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- **Dynamic Content:** Tests are point-in-time; may miss issues in SPAs or dynamic updates
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- **Shadow DOM:** Limited support for components using Shadow DOM
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---
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## Integration Examples
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### CI/CD Integration
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```yaml
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# .github/workflows/accessibility.yml
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name: Accessibility Tests
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on: [push, pull_request]
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jobs:
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a11y-test:
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runs-on: ubuntu-latest
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steps:
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- uses: actions/checkout@v2
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- name: Start cremote daemon
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run: cremote-daemon &
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- name: Run accessibility tests
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run: |
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cremote navigate --url http://localhost:3000
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cremote inject-axe
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cremote run-axe --run-only wcag2aa > axe-results.json
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cremote contrast-check > contrast-results.txt
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- name: Upload results
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uses: actions/upload-artifact@v2
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with:
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name: accessibility-results
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path: |
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axe-results.json
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contrast-results.txt
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```
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### Programmatic Usage (Go)
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```go
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import "git.teamworkapps.com/shortcut/cremote/client"
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client := client.NewClient("localhost:9223")
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// Run axe tests
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client.InjectAxeCore("", "4.8.0", 30)
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results, _ := client.RunAxeCore("", nil, nil, 30)
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// Check contrast
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contrastResults, _ := client.CheckContrast("", "body", 10)
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// Test keyboard navigation
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keyboardResults, _ := client.TestKeyboard("", 10)
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```
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---
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## Support and Resources
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- **WCAG 2.1 Guidelines:** https://www.w3.org/WAI/WCAG21/quickref/
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- **Axe-Core Documentation:** https://github.com/dequelabs/axe-core
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- **Cremote Repository:** git.teamworkapps.com/shortcut/cremote
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- **Issue Tracker:** git.teamworkapps.com/shortcut/cremote/issues
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---
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**Last Updated:** 2025-10-02
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**Version:** 1.0.0
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