klytos-seo-and-indexing

name	klytos-seo-and-indexing
description	Guide for SEO, sitemap.xml, llms.txt, and search engine and AI indexing in Klytos CMS. Use when asking about SEO, sitemap, robots.txt, llms.txt, meta tags, Open Graph, structured data, search engine optimization, AI indexing, page indexing, canonical URLs, hreflang tags, JSON-LD schema, or the build engine SEO process.

Klytos SEO & Indexing Guide

Overview

Klytos generates 100% static HTML pages. SEO is handled during the build process: the BuildEngine injects all necessary meta tags, generates sitemap.xml, robots.txt, and LLM discoverability files (llms.txt, llms-full.txt, per-page .html.md) automatically.

Meta Tags (injected in every page )

<!-- Generator identification -->
<meta name="generator" content="Klytos {version}">

<!-- Basic SEO -->
<title>{page_title} — {site_name}</title>
<meta name="description" content="{meta_description}">
<link rel="canonical" href="{canonical_url}">

<!-- Open Graph (Facebook, LinkedIn, etc.) -->
<meta property="og:type" content="website">
<meta property="og:title" content="{page_title}">
<meta property="og:description" content="{meta_description}">
<meta property="og:url" content="{canonical_url}">
<meta property="og:image" content="{og_image}">
<meta property="og:site_name" content="{site_name}">
<meta property="og:locale" content="{locale}">

<!-- Twitter Cards -->
<meta name="twitter:card" content="summary_large_image">
<meta name="twitter:title" content="{page_title}">
<meta name="twitter:description" content="{meta_description}">
<meta name="twitter:image" content="{og_image}">

<!-- Multilingual (hreflang) -->
<link rel="alternate" hreflang="{lang}" href="{url}">

<!-- JSON-LD Structured Data -->
<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "WebPage",
  "name": "{page_title}",
  "description": "{meta_description}",
  "url": "{canonical_url}",
  "publisher": {
    "@type": "Organization",
    "name": "{site_name}"
  }
}
</script>

sitemap.xml

Auto-generated during build. Includes all published pages with:

• <loc> — full canonical URL
• <lastmod> — page last modification date (ISO 8601)
• <changefreq> — based on page type (homepage: daily, others: weekly)
• <priority> — homepage: 1.0, top-level pages: 0.8, nested: 0.6

Plugins can add URLs via the build.sitemap_urls filter.

Note: .md and llms*.txt files are NOT included in sitemap.xml — only .html pages.

robots.txt

Auto-generated with:

User-agent: *
Allow: /
Sitemap: {site_url}/sitemap.xml
# AI-friendly content index
# llms.txt: {site_url}/llms.txt

# Additional rules from admin settings
{robots_extra}

LLM Discoverability (AI-Ready Content)

Klytos is the first CMS with native LLM discoverability. Following the llms.txt specification (https://llmstxt.org/), the build engine generates three types of files for AI agents (ChatGPT, Claude, Perplexity, Gemini) to discover and cite content.

Configuration (site config seo object)

Field	Type	Default	Description
llms_txt_enabled	boolean	true	Generate /llms.txt
llms_full_txt_enabled	boolean	true	Generate /llms-full.txt
llms_md_pages_enabled	boolean	true	Generate per-page .html.md files

All enabled by default — LLM compatibility comes out of the box.

Page-level LLM fields

Field	Type	Default	Description
llm_optional	boolean	false	Moves page to "Optional" section of llms.txt
llm_exclude	boolean	false	Excludes page from all LLM files (llms.txt, llms-full.txt, .html.md)

Typical usage: mark legal pages (privacy, legal notice) as llm_optional, and exclude internal/staging pages with llm_exclude.

/llms.txt (curated index)

# {site_name}

> {site_description}

{tagline}

## Pages

- [{page_title}]({page_url}): {meta_description}

## Optional

- [{page_title}]({page_url}): {meta_description}

Ordering: index (home) first, then default language pages, then other languages.

/llms-full.txt (complete content)

Single Markdown file with full content of every published page. Allows an AI agent to load the entire site in one request. Uses proper Markdown conversion (headings, lists, links, images, tables) via the HtmlToMarkdown class.

Per-page .html.md files

Each published page gets a Markdown version at {slug}/index.html.md with:

• H1 title, blockquote description
• URL, Language, Last modified metadata
• Full page content in clean Markdown

HtmlToMarkdown converter

File: core/html-to-markdown.php — Pure PHP, no external dependencies.

Converts HTML to clean Markdown:

• Headings, paragraphs, bold/italic, links, images
• Ordered/unordered lists
• Blockquotes, code blocks, inline code
• Tables (pipe format with header separator)
• Horizontal rules, line breaks

Strips non-content elements: script, style, noscript, form, iframe, nav, header, footer, HTML comments, Klytos block markers.

.htaccess headers

The build engine adds rules so .md and llms*.txt files are served with:

• Content-Type: text/markdown; charset=utf-8
• X-Robots-Tag: noindex (prevents Google from indexing duplicate content)

MCP Tools for SEO

• klytos_build_site — Full site build (regenerates all SEO + LLM files)
• klytos_build_page — Rebuild single page (regenerates both .html and .html.md)
• klytos_get_build_status — Includes LLM config status
• klytos_rebuild_block — Smart rebuild a global block (does NOT regenerate .md files)
• klytos_rebuild_css — Regenerate CSS only

Extending SEO & LLM via Plugins

// Add custom URLs to sitemap.xml
klytos_add_filter('build.sitemap_urls', function (array $urls): array {
    $urls[] = [
        'loc'        => 'https://example.com/custom-page',
        'lastmod'    => '2025-01-15',
        'changefreq' => 'monthly',
        'priority'   => '0.5',
    ];
    return $urls;
});

// Add custom rules to robots.txt
klytos_add_filter('build.robots_txt', function (string $robots): string {
    $robots .= "\nDisallow: /private/\n";
    return $robots;
});

// Inject custom meta tags into <head>
klytos_add_filter('build.head_html', function (string $head): string {
    $head .= '<meta name="custom-tag" content="value">';
    return $head;
});

// Add entries to llms.txt (e.g., blog posts from a plugin)
klytos_add_filter('build.llms_pages', function (array $pages): array {
    $pages[] = [
        'slug'             => 'blog/my-post',
        'title'            => 'My Blog Post',
        'lang'             => 'en',
        'meta_description' => 'A blog post about something',
        'markdown_content' => 'The full content in Markdown...',
        'is_index'         => false,
        'llm_optional'     => false,
        'llm_exclude'      => false,
        'updated_at'       => '2026-04-05T10:00:00Z',
    ];
    return $pages;
});

// Modify llms.txt content before writing
klytos_add_filter('build.llms_txt', function (string $content): string {
    return $content;
});

// Modify llms-full.txt content before writing
klytos_add_filter('build.llms_full_txt', function (string $content): string {
    return $content;
});

// Modify per-page Markdown before writing
klytos_add_filter('build.page_markdown', function (string $md, array $page): string {
    return $md;
});

// React after LLM files are generated
klytos_add_action('build.llms_generated', function (array $stats): void {
    // $stats: md_files_built, llms_txt_generated, llms_full_txt_generated
});