Playwright Scanner

playwright-scanner Agent

Type: Hidden helper sub-agent (not user-invokable)
Platforms: Copilot (.github/agents/playwright-scanner.agent.md), Claude Code (.claude/agents/playwright-scanner.md)
Invoked by: web-accessibility-wizard during Phase 10 (Behavioral Testing)

Purpose

Behavioral accessibility testing using Playwright. Runs live browser-based tests that detect accessibility defects which cannot be found by static code review or axe-core CLI scans — keyboard traps, focus management failures, dynamic state violations, responsive reflow issues, and computed contrast failures after CSS cascade.

MCP Tools Used

Tool	What It Tests
run_playwright_keyboard_scan	Tab-order sequence, keyboard traps
run_playwright_state_scan	axe-core violations in dynamic states (menus, modals, accordions)
run_playwright_viewport_scan	Reflow failures, touch target sizes at multiple viewports
run_playwright_contrast_scan	Computed foreground/background contrast ratios
run_playwright_a11y_tree	Browser accessibility tree snapshot

Scan Modes

• full — Run all 5 scan types (default)
• keyboard-only — Tab traversal and trap detection
• states-only — Dynamic state scanning
• viewport-only — Responsive viewport scanning
• contrast-only — Computed contrast verification
• tree-only — Accessibility tree snapshot

Output Contract

Returns structured text with sections for each scan type, including finding counts, per-element details, and overall behavioral confidence (High/Medium/Low based on how many scans completed successfully).

Dependencies

• Required: playwright (npm package)
• Optional enhancement: @axe-core/playwright (enables state scan and viewport scan)
• Graceful degradation: Runs available scans, reports which are unavailable

Skills

• playwright-testing — Scan patterns, test templates, CI integration
• web-severity-scoring — Finding severity classification

Related Agents

• web-accessibility-wizard — Orchestrator that dispatches this agent
• playwright-verifier — Fix verification counterpart
• cross-page-analyzer — Consumes accessibility tree diffs across pages