---
name: qa-browser-automation
description: >
  Browser-based QA combining Chrome MCP control with Python analysis tools. Use when
  performing browser QA testing, visual regression tracking, WCAG accessibility auditing,
  performance profiling, or health-scoring web applications.
license: MIT + Commons Clause
metadata:
  version: 2.1.0
  author: borghei
  category: engineering
  domain: quality-assurance
  updated: 2026-04-02
  tags: [browser-qa, wcag, visual-regression, health-scoring]
  python-tools: qa_health_scorer.py, accessibility_auditor.py, visual_regression_tracker.py, test_report_generator.py
  tech-stack: python, chrome-mcp, accessibility, wcag, performance
---
# QA Browser Automation

The agent drives Chrome MCP for live browser testing and uses four Python tools for deterministic health scoring, accessibility auditing, visual regression tracking, and report generation.

---

## Quick Start

```bash
# Score QA findings (0-100 weighted across 10 categories)
python scripts/qa_health_scorer.py findings.json --threshold 85 --baseline .qa-baselines/latest.json --save-baseline --json

# Audit HTML for WCAG 2.1 violations
python scripts/accessibility_auditor.py page.html --level AA --json

# Track visual regressions
python scripts/visual_regression_tracker.py --init --baseline-dir ./baselines
python scripts/visual_regression_tracker.py --register ./baselines
python scripts/visual_regression_tracker.py --baseline ./baselines --current ./screenshots --threshold 5

# Generate full QA report
python scripts/test_report_generator.py session_data.json --format markdown -o report.md
```

## Tools Overview

| Tool | Input | Output |
|------|-------|--------|
| `qa_health_scorer.py` | Findings JSON | Score 0-100, grade A-F, category breakdown, trend data |
| `accessibility_auditor.py` | HTML file (or stdin) | WCAG violations by level with remediation guidance |
| `visual_regression_tracker.py` | Baseline + current screenshot dirs | Pass/fail per page, change percentages |
| `test_report_generator.py` | Session data JSON | Markdown or JSON report with recommendations |

All tools support `--json` for machine output. Health scorer and regression tracker return exit code 1 on failure (CI-friendly).

---

## Workflow 1: Full Application QA Sweep (11 Phases)

**Phase 1-2: Pre-flight and authentication.**
- Verify `git status` is clean. Abort if dirty.
- Create session directory: `.qa-sessions/{timestamp}/`
- Authenticate via Chrome MCP if needed.

**Phase 3-4: Orient and explore.**
- Use `mcp__claude-in-chrome__read_page` to build sitemap/page map.
- Navigate each route. Check `read_console_messages` for errors, `read_network_requests` for 4xx/5xx.
- Test all forms with valid data, empty submissions, and boundary values.

**Phase 5: State testing.**
- Verify loading states (skeleton screens, not blank), empty states (guides to first action), error states, success states, partial states.
- **Four shadow paths per interaction:** happy path, nil input, empty input, error upstream.

**Phase 6: Cross-device and security.**
- Resize to 320px, 768px, 1024px, 1440px, 1920px.
- Check touch targets (44x44px min), layout shifts.
- Verify security headers (CSP, HSTS, X-Frame-Options), cookie flags.

**Phase 7-8: Document and score.**
- Record every finding with screenshot evidence. No finding without evidence.
- Classify by severity (P0-P4) and category (10 categories).
- Run: `python scripts/qa_health_scorer.py findings.json --baseline .qa-baselines/latest.json`

**Phase 9: Triage and fix loop.**
- P3/P4: AUTO-FIX, commit atomically, verify.
- P0/P1/P2: ASK, present evidence, propose fix, wait for approval.
- After each fix: re-run check. If fail: `git revert`.
- Hard stop at 50 fixes.

**Phase 10-11: Regression check and report.**
- Re-visit fixed pages. Verify no new errors.
- Generate report: `python scripts/test_report_generator.py session.json --save-baseline`

**Validation checkpoint:** Health score >= 85. Zero P0 findings. WCAG AA >= 95%.

---

## Workflow 2: Visual Regression Testing

```bash
# Set up baseline
python scripts/visual_regression_tracker.py --init --baseline-dir ./baselines
# Capture and register screenshots
python scripts/visual_regression_tracker.py --register ./baselines
# After changes, compare
python scripts/visual_regression_tracker.py --baseline ./baselines --current ./screenshots --threshold 5 --json
# Accept intentional changes
python scripts/visual_regression_tracker.py --update-baseline --baseline ./baselines --current ./screenshots
```

Pages exceeding the threshold (default 5%) are flagged as regressions. Uses SHA-256 hashing and byte-level comparison.

---

## Workflow 3: Accessibility Audit

```bash
python scripts/accessibility_auditor.py page.html --level AA --json
curl -s https://example.com | python scripts/accessibility_auditor.py - --level AAA
```

**What gets checked by level:**
- **A (Must Fix):** Alt text, page language, form labels, headings, duplicate IDs, autoplay media
- **AA (Should Fix):** Color contrast (4.5:1 text, 3:1 large), heading hierarchy, focus visible, error identification
- **AAA (Nice to Have):** Enhanced contrast (7:1), extended audio, reading level

Each violation includes: WCAG criterion, severity, element selector, and remediation guidance.

---

## Testing Tiers

| Tier | Duration | Scope |
|------|----------|-------|
| **Quick** | 30s | Console errors, broken links, basic a11y, mobile resize |
| **Standard** | 2-5 min | + Top 10 routes, forms, contrast, Core Web Vitals |
| **Deep** | 10-20 min | + Full sitemap, state testing, WCAG AA, performance, visual regression, security headers |
| **Exhaustive** | 30+ min | + Every element, WCAG AAA, all pages performance, 5 breakpoints, auth edge cases, memory leaks |

---

## Health Scoring System

10 weighted categories, score 0-100:

| Category | Weight | Measures |
|----------|--------|----------|
| Functional | 18% | Forms, CRUD, navigation flows |
| Accessibility | 13% | WCAG compliance, keyboard nav |
| Console Errors | 12% | JS errors, unhandled rejections |
| UX Flow | 12% | Logical navigation, clear feedback |
| Performance | 12% | Core Web Vitals within thresholds |
| Visual Consistency | 10% | Layout shifts, alignment, z-index |
| Broken Links | 8% | HTTP 4xx/5xx, dead anchors |
| Content Quality | 5% | Spelling, placeholder text, truncation |
| Security Headers | 5% | CSP, HSTS, cookie flags |
| Mobile Responsive | 5% | Breakpoints, touch targets, no h-scroll |

**Severity deductions:** P0: -30, P1: -18, P2: -10, P3: -4, P4: -1.

**Grades:** A (90-100), B (80-89), C (70-79), D (60-69), F (0-59).

---

## Safety Controls

- **Clean working tree required** -- abort if `git status` dirty.
- **Max 50 fixes per session** -- hard stop.
- **Risk accumulator** -- component (+5), style (+2), config (+8), revert (+15). Stop at 25% of budget.
- **WTF heuristic** -- 3 consecutive fix verification failures = stop entirely.
- **Atomic commits** -- one fix = one commit: `fix(qa): [P{severity}] {description}`

---

## Troubleshooting

| Problem | Cause | Solution |
|---------|-------|----------|
| Scorer exits code 1 with no errors | Score below `--threshold` (default 70) | Check score in output; raise threshold or fix findings |
| Auditor reports `parse-error` | Malformed HTML | Verify file is complete; check curl is not returning redirect |
| Regression tracker 100% change on all pages | Baseline manifest empty | Run `--init` then `--register` before comparing |
| Findings default to P3/functional | Missing `severity` or `category` keys | Include both keys in each finding dict |
| Chrome MCP returns stale content after SPA nav | DOM updated without full page load | Wait for transition, call `read_page` again |

---

## References

| Guide | Path |
|-------|------|
| Browser Testing Methodology | `references/browser_testing_methodology.md` |
| WCAG Compliance Guide | `references/wcag_compliance_guide.md` |
| Performance Benchmarks | `references/performance_benchmarks.md` |

---

## Integration Points

| Skill | Integration |
|-------|-------------|
| `code-reviewer` | Health score and findings in PR review context |
| `senior-frontend` | Visual regression baselines align with component library |
| `senior-devops` | Health score gates CI/CD via exit code |
| `senior-secops` | Security header findings escalate to security review |
| `incident-commander` | P0 findings trigger incident response |

---

**Last Updated:** April 2026
**Version:** 2.1.0