name: website-analyzer
description: Analyze a website's UI/UX, category, style, performance, surface security, and SEO; emit structured JSON. Use for URL audits or website-cloner input. Don't use for penetration tests, full SEO audits, or App Store ASO.
license: MIT
effort: high
metadata:
    version: 1.3.0
    author: "Luong NGUYEN <luongnv89@gmail.com>"

Website Analyzer

Analyzes any website URL across 6 dimensions and produces structured JSON output for downstream skills in the website-cloner suite.

When to Use

Trigger when the user asks to:

• Analyze, audit, or scan a website
• Get a performance, SEO, security, or UI/UX assessment of a URL
• Understand a website's structure, style, or category

Do not use for full penetration testing, deep security audits, or App Store ASO.

Prerequisites

1. Require a valid http:// or https:// URL and an output path or stdout destination.
2. Confirm page-fetch access is available; never bypass authentication, paywalls, or bot protections.
3. When an output path is supplied, validate that its directory exists and is writable; skip this check for stdout.
4. If any prerequisite fails, return a descriptive error with the failing input and corrective action.

Workflow

1. Fetch page content via WebFetch
2. Extract HTML structure, metadata, headings, links, images, scripts
3. Estimate performance metrics (LCP, CLS, TTFB, page weight, request count)
4. Run surface-level security checks
5. Score SEO across 5 weighted dimensions
6. Classify UI/UX layout, category, and style
7. Output structured JSON

Output

Produce structured JSON at the requested output path (or stdout):

{
  "url": "https://example.com",
  "timestamp": "2026-05-07T12:00:00Z",
  "ui_ux": {
    "layout": "single-column | two-column | grid | ...",
    "visual_hierarchy": "what draws attention first",
    "components": ["nav", "hero", "cta", "footer", ...],
    "responsive": "desktop-first | mobile-first | adaptive | unknown",
    "friction_points": ["slow nav", "missing CTA", ...]
  },
  "category": "saas-landing | portfolio | e-commerce | blog | docs | dashboard | ...",
  "category_confidence": 0.9,
  "style": {
    "typography": "brief description",
    "palette": ["#hex", ...],
    "spacing": "compact | comfortable | spacious",
    "motion": "minimal | moderate | heavy",
    "aesthetic": "vibe description"
  },
  "performance": {
    "lcp_estimate_seconds": 2.5,
    "cls_estimate": 0.05,
    "ttfb_estimate_seconds": 0.3,
    "total_page_weight_kb": 1200,
    "request_count": 45,
    "notes": "estimated from static analysis"
  },
  "security": {
    "https": true,
    "mixed_content": false,
    "security_headers": ["strict-transport-security", ...],
    "exposed_metadata": [],
    "note": "Surface-level check only. Not a full security audit."
  },
  "seo": {
    "score": 72,
    "title_tag": "present | missing | duplicate",
    "meta_description": "present | missing | too-short",
    "heading_structure": "h1:N h2:N ...",
    "alt_text_coverage": 0.85,
    "structured_data": "present | missing",
    "canonical_url": "present | missing",
    "robots_sitemap": "robots=ok | sitemap=found | ...",
    "dimension_scores": {
      "meta_tags": 80,
      "heading_structure": 60,
      "image_alt_text": 90,
      "structured_data": 50,
      "crawlability": 75
    }
  }
}

Step 1: Fetch the Page

Use WebFetch to retrieve content:

WebFetch(url=<url>, prompt="Extract all HTML structure, meta tags, headings, links, images, scripts, styles, and any structured data (JSON-LD, Open Graph, etc.)")

If WebFetch fails (4xx, 5xx, timeout), return immediately:

{"url": "<url>", "error": "unreachable", "detail": "<error>"}

For JS-heavy SPAs where WebFetch returns minimal content, note:

{"note": "SPA detected — analysis based on crawlable content only; some metrics may be incomplete"}

Step 2: Extract Structure

From fetched content, extract:

• <title>, <meta> tags (description, keywords, OG, Twitter)
• Heading hierarchy (<h1>–<h6>)
• Images with alt attributes
• Link structure and count
• Script/style count and sizes
• JSON-LD structured data
• Canonical URL
• Robots meta tag

Step 3: Estimate Performance

All metrics are estimates from static analysis. Note this in output.

Step 4: Security Check (Surface-Level Only)

Check:

• HTTPS usage
• Mixed content (HTTP resources on HTTPS page)
• Security headers: HSTS, X-Content-Type-Options, X-Frame-Options, CSP
• Exposed metadata (dev tools, debug endpoints, sensitive data in comments)

Always label as surface-level.

Step 5: SEO Scoring

Compute each dimension's 0–100 sub-score using the rubrics below, then combine with the weights to yield the overall seo.score. Round each sub-score to the nearest integer; the final score is round(Σ weight_i × sub_i).

When a sub-score cannot be computed (e.g. robots.txt unreachable), record the dimension as null in dimension_scores and exclude it from the weighted sum, redistributing its weight proportionally across the remaining dimensions. Note any nulls in seo.notes.

Step 6: UI/UX, Category, Style

• Layout: Infer from HTML structure (divs, sections, nav, main, footer)
• Category: saas-landing | portfolio | e-commerce | blog | docs | dashboard | marketing-site | web-app | other
• Style: Typography, color palette, spacing density, motion indicators, aesthetic vibe

Edge Cases and Error Handling

Acceptance Criteria

Verify the expected output before reporting success:

• JSON parses and contains url, timestamp, ui_ux, category, style, performance, security, and seo.
• seo.score is an integer from 0 through 100 and matches the weighted, null-adjusted dimension calculation.
• Performance estimates use lcp_estimate_seconds, unitless cls_estimate, ttfb_estimate_seconds, and total_page_weight_kb, plus an explicit static-analysis limitation.
• Every unavailable measurement is null or an error field, never an invented value.
• The output is written to the requested destination; assert the file exists and can be parsed when a path is supplied.

Step Completion Report

Emit this after analysis:

◆ Analyze Website
··································································
  Input fetched:        √ pass | × fail ([reason])
  Six dimensions:      √ pass | × partial ([missing])
  SEO calculation:     √ pass | × partial ([null dimensions])
  Output JSON:         √ pass ([path or stdout])
  Result:              PASS | PARTIAL | FAIL

Report PASS only when the JSON is valid and all six top-level dimensions are present; use PARTIAL for explicitly labeled crawlability gaps.