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html-structure-validate

Included with Lifetime
$97 forever

Validate HTML5 structure and basic syntax. BLOCKING quality gate - stops pipeline if validation fails. Ensures deterministic output quality.

Web Dev

What this skill does


# HTML Structure Validate Skill

## Purpose

This skill is a **BLOCKING quality gate** that ensures generated HTML meets minimum structural requirements. It is the **first deterministic validation** of probabilistic AI-generated output.

The skill checks:
- **HTML5 compliance** - Proper DOCTYPE, tags
- **Tag closure** - All tags properly closed
- **Required elements** - Meta tags, stylesheet links
- **Well-formedness** - Valid structure

If validation fails, the pipeline **STOPS** and triggers a hook to notify the user.

This enforces the principle: **Python validates, ensuring deterministic quality**.

## What to Do

1. **Load HTML file to validate**
   - Read `04_page_XX.html` generated by AI skill
   - Verify file exists and is readable
   - Confirm file is text (not binary)

2. **Run validation checks**
   - Check HTML5 structure compliance
   - Verify tag closure
   - Validate head section
   - Check required CSS link
   - Validate page container structure

3. **Generate validation report**
   - Document all checks performed
   - List any errors found
   - Note warnings (non-blocking)
   - Record informational findings

4. **Save validation report** as JSON
   - Save to: `output/chapter_XX/page_artifacts/page_YY/06_validation_structure.json`
   - Include timestamp
   - Include all check results

5. **Exit with appropriate code**
   - Return 0 if VALID (continue pipeline)
   - Return 1 if INVALID (STOP pipeline, trigger hook)

## Input Parameters

```
html_file: <str>         - Path to 04_page_XX.html
output_dir: <str>        - Directory for validation report
strict_mode: <bool>      - If true, warnings also fail (default: false)
page_number: <int>       - Page number (for reporting)
chapter: <int>           - Chapter number (for reporting)
```

## Validation Checks

### Check 1: DOCTYPE Declaration

**Requirement**: File must start with proper DOCTYPE
```html
<!DOCTYPE html>
```

**Check**:
- [ ] File contains `<!DOCTYPE html>` (case-insensitive)
- [ ] DOCTYPE appears before any tags
- [ ] DOCTYPE is on first line or near beginning

**Error if**: Missing or incorrect DOCTYPE

### Check 2: HTML Tags

**Requirement**: Proper `<html>` opening and closing tags
```html
<html lang="en">
    ...
</html>
```

**Checks**:
- [ ] `<html>` tag present
- [ ] `</html>` closing tag present
- [ ] Tags are properly paired
- [ ] No unclosed `<html>` tags

**Error if**: Missing either tag or improperly paired

### Check 3: Head Section

**Requirement**: Complete `<head>` section with metadata
```html
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>...</title>
    <link rel="stylesheet" href="../../styles/main.css">
</head>
```

**Checks**:
- [ ] `<head>` and `</head>` tags present
- [ ] `<meta charset="UTF-8">` present
- [ ] `<meta name="viewport">` present (warning if missing)
- [ ] `<title>` tag with content present
- [ ] CSS `<link>` tag present with href attribute

**Error if**: Missing charset, title, or CSS link
**Warning if**: Missing viewport meta tag

### Check 4: Body Section

**Requirement**: Proper `<body>` tags with content
```html
<body>
    <div class="page-container">
        <main class="page-content">
            ...
        </main>
    </div>
</body>
```

**Checks**:
- [ ] `<body>` and `</body>` tags present
- [ ] `<div class="page-container">` present
- [ ] `<main class="page-content">` present inside container
- [ ] Body contains substantial content (> 100 bytes)

**Error if**: Missing tags or required container divs

### Check 5: Tag Closure Validation

**Requirement**: All tags must be properly closed

**Checks for**:
- Unmatched opening tags (e.g., `<p>` without `</p>`)
- Improper nesting (e.g., `<p><h2>text</h2></p>`)
- Self-closing tags used correctly (e.g., `<br/>`, `<img/>`)
- Comment blocks properly formatted (`<!-- -->`)

**Validation method**:
- Parse HTML into tree structure
- Verify all nodes properly matched
- Check nesting doesn't violate HTML5 rules

**Error if**: Any unmatched or improperly nested tags

### Check 6: Heading Tags (h1-h6)

**Requirement**: Valid heading hierarchy
```html
<h1>Chapter Title</h1>
<h2>Section Heading</h2>
<h3>Subsection</h3>
```

**Checks**:
- [ ] All heading tags properly closed
- [ ] First heading should be h1 (warning if not)
- [ ] Heading levels don't skip dramatically (h1 → h4 is suspicious)
- [ ] All headings have text content (not empty)

**Error if**: Heading tags improperly closed
**Warning if**: Suspicious hierarchy

### Check 7: Content Structure

**Requirement**: Meaningful content in page container

**Checks**:
- [ ] `<main class="page-content">` contains elements
- [ ] Content includes headings or paragraphs
- [ ] No completely empty content area
- [ ] Text nodes or elements present (> 100 words total)

**Error if**: No content or empty structure

### Check 8: List Integrity

**Requirement**: All lists properly structured

**Checks** for each `<ul>` or `<ol>`:
- [ ] List opening and closing tags matched
- [ ] List contains `<li>` elements
- [ ] All `<li>` tags properly closed
- [ ] `<li>` count matches opening/closing pairs
- [ ] No nested `<ul>` or `<ol>` improperly closed

**Error if**: Empty lists or unmatched `<li>` tags

### Check 9: Image and Link Tags

**Requirement**: Self-closing tags properly formatted

**Checks**:
- [ ] All `<img>` tags have `src` and `alt` attributes
- [ ] All `<a>` tags have valid `href` attributes
- [ ] Image paths don't have obvious errors (no broken syntax)
- [ ] Self-closing tags use proper syntax

**Warning if**: Images missing alt text or links missing href

### Check 10: Table Tags (if present)

**Requirement**: Proper table structure

**Checks**:
- [ ] `<table>`, `<tr>`, `<td>`, `<th>` tags properly nested
- [ ] All rows have consistent column counts
- [ ] Table headers and body properly structured

**Error if**: Malformed table structure

## Validation Report Format

### Output: `06_validation_structure.json`

```json
{
  "page": 16,
  "book_page": 17,
  "chapter": 2,
  "validation_type": "structure",
  "validation_timestamp": "2025-11-08T14:34:00Z",
  "overall_status": "PASS",
  "error_count": 0,
  "warning_count": 1,
  "checks_performed": [
    {
      "check_name": "DOCTYPE Declaration",
      "status": "PASS",
      "details": "Valid HTML5 DOCTYPE found"
    },
    {
      "check_name": "HTML Tags",
      "status": "PASS",
      "details": "Proper <html> opening and closing tags"
    },
    {
      "check_name": "Head Section",
      "status": "PASS",
      "details": "All required meta tags and title present"
    },
    {
      "check_name": "Body Section",
      "status": "PASS",
      "details": "Body and content structure valid"
    },
    {
      "check_name": "Tag Closure",
      "status": "PASS",
      "details": "All tags properly matched and closed"
    },
    {
      "check_name": "Heading Hierarchy",
      "status": "PASS",
      "details": "4 headings found, proper h1-h4 hierarchy"
    },
    {
      "check_name": "Content Structure",
      "status": "PASS",
      "details": "Main content area contains 245 words across 3 paragraphs"
    },
    {
      "check_name": "List Integrity",
      "status": "PASS",
      "details": "1 list with 3 items, all properly formed"
    },
    {
      "check_name": "Image Tags",
      "status": "PASS",
      "details": "No images on this page"
    },
    {
      "check_name": "Table Tags",
      "status": "PASS",
      "details": "No tables on this page"
    }
  ],
  "errors": [],
  "warnings": [
    {
      "check": "Heading Hierarchy",
      "message": "First heading is h2, typically should be h1 for page opening",
      "severity": "LOW"
    }
  ],
  "summary": {
    "total_checks": 10,
    "passed": 9,
    "failed": 0,
    "warnings": 1,
    "html_valid": true,
    "tags_matched": true,
    "content_substantial": true
  }
}
```

## Validation Rules

### PASS Criteria
- DOCTYPE present and valid
- All required tags (`html`,
Files: 2
Size: 27.7 KB
Complexity: 32/100
Category: Web Dev
Source: https://github.com/aiskillstore/marketplace/tree/main/skills/abejitsu/html-structure-validate

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