Description
Modern AI agents (ChatGPT, Claude, Perplexity, Gemini, etc.) work much better with Markdown than HTML. Umay AI Markdown inspects the incoming Accept header and, only when text/markdown is requested, intercepts the response and serves a clean, agent-friendly Markdown representation of the page.
Browsers, search engines, and any client that does not explicitly ask for Markdown receive the unchanged HTML response. There is no settings page, no cron job, and no external service call.
Key features
- Zero configuration — install, activate, done.
- Only triggers when
Accept: text/markdownis present. Regular visitors and search engines are never affected. - Hybrid content extraction: uses
the_contentfor posts/pages, falls back to a DOM-based extractor for archives, taxonomies, and the homepage. - Powered by the industry-standard league/html-to-markdown library.
- Transient-cached for 12 hours per URL (sha256-keyed). Auto-invalidated on
save_post, term edits, theme switches, and menu updates. - Built-in IP rate limiter (30 requests / minute by default) to mitigate abuse.
- Strict input sanitization, header injection protection, libxml entity hardening (XXE-safe), and full WordPress Coding Standards compliance.
- PSR-4 autoloaded, namespaced OOP code. No globals.
- Sends
Vary: Accept,X-Robots-Tag: noindex, andX-Content-Type-Options: nosniffon every Markdown response.
What gets sent to AI agents
Each Markdown response includes a YAML front-matter block with the page title, site name, canonical URL, and ISO-8601 generation timestamp, followed by the page body converted to Markdown. Navigation, footer, sidebars, scripts, styles, comment forms, related posts, and other page chrome are stripped before conversion.
Filters
Two filters are available for advanced customization:
umay_mdn_bypass— Returntrueto skip Markdown handling for the current request.umay_mdn_cache_ttl— Override the default 12-hour cache lifetime (in seconds, minimum 60).umay_mdn_rate_limit— Override the default 30-requests-per-minute rate limit.umay_mdn_converter_options— Modify the league/html-to-markdown converter options array.
Screenshots

Markdown response served when an AI agent requests Accept: text/markdown— full HTTP headers (Content-Type, Vary, X-Cache, X-Robots-Tag, X-Content-Type-Options, X-Markdown-Generator), followed by a YAML frontmatter block (title, site, URL, generated timestamp) and the converted Markdown body.
Built-in transient cache in action: the first request to a URL returns X-Cache: MISS(Markdown generated on the fly), the next request to the same URL returnsX-Cache: HIT(served from cache, no rendering work).
Transparent content negotiation: same WordPress URL, two different responses based on the Acceptrequest header — browsers receivetext/html(the normal theme output), AI agents receivetext/markdown(clean, machine-readable content) with the plugin’s enriched header set.
Installation
- Upload the
markdown-negotiatorfolder (or the ZIP) via Plugins > Add New > Upload Plugin. - Activate the plugin.
- There is no settings page. The plugin starts working immediately.
To verify:
curl -H "Accept: text/markdown" https://your-site.com/
You should get back a Content-Type: text/markdown; charset=utf-8 response with a YAML front-matter and a Markdown body.
FAQ
-
Does it slow down my normal site?
-
No. The plugin returns immediately on
template_redirectpriority 1 if the request does not includeAccept: text/markdown. The cost is roughly a singleifcheck per request. -
Does this plugin contact any external services?
-
No. The plugin does not call any external service, does not send analytics, does not check for updates against a remote server, and does not load any remote assets. All HTML-to-Markdown conversion happens locally using the bundled
league/html-to-markdownlibrary. -
How is the cache invalidated?
-
Per-URL cache keys are deleted on
save_postandtransition_post_statusfor the affected post. Term edits, theme switches, and menu updates flush the entire Markdown cache. -
Is logged-in personalization supported?
-
No. Logged-in requests always fall back to HTML to avoid leaking nonces, admin bars, or per-user content into a shared Markdown cache. This is by design.
-
How do I clear the cache manually?
-
Deactivate and re-activate the plugin. Deactivation calls
Cache::flush_all(). -
Is the Markdown response indexable by search engines?
-
No. Every Markdown response includes
X-Robots-Tag: noindexto prevent duplicate-content issues. The HTML version remains the canonical, indexable representation. -
Does this work with caching plugins like LiteSpeed Cache, WP Rocket, or W3 Total Cache?
-
The plugin sets
Vary: Acceptso any well-behaved cache layer will store the Markdown and HTML variants separately. If your cache layer ignores the Vary header, exclude the URLs from the cache when theAccept: text/markdownheader is present.
Reviews
There are no reviews for this plugin.
Contributors & Developers
“Umay AI Markdown” is open source software. The following people have contributed to this plugin.
ContributorsTranslate “Umay AI Markdown” into your language.
Interested in development?
Browse the code, check out the SVN repository, or subscribe to the development log by RSS.
Changelog
1.1.1
- Aligned text domain with WordPress.org plugin slug: changed from
umay-ai-markdowntomarkdown-negotiatoracross plugin header, gettext calls, and POT file (per WP.org review feedback). - Hardened Markdown response output: replaced raw
echo $markdownwithwp_kses( $markdown, array() )to satisfy Plugin Check’s late-escape rule while preserving Markdown syntax. - Removed bundled tr_TR translation files; only the English POT template ships in the WordPress.org distribution. Translations now flow through translate.wordpress.org.
1.1.0
- Renamed plugin: “Markdown Negotiator” “Umay AI Markdown”; slug and text domain changed to
markdown-negotiator(per WordPress.org review feedback to ensure the name is distinctive). - Removed deprecated
libxml_disable_entity_loader()calls inContentExtractorandConverter. XXE protection unchanged: libxml 2.9+ disables external entities by default, andLIBXML_NONETis still passed toloadHTML(). - Refactored Tier 2 (non-singular) request pipeline: replaced the open
ob_start( $callback )ontemplate_redirectwith atemplate_includefilter that opens and closes its buffer (ob_startpaired withob_get_clean) inside a single function scope, satisfying Plugin Check’s buffer-pairing requirement. - Added
try/catcharound the template render so a fatal in a theme/plugin returns a clean 500 instead of a half-buffered response.
1.0.1
- HTML sanitization hardening: strip
<style>,<script>,<noscript>blocks via regex (defense in depth on top of league/html-to-markdown’sremove_nodes). - Lazy-load image normalization: promotes
data-lazy-src/data-src/data-originaland the firstsrcsetURL into the realsrc. Drops empty/placeholder images. - Page-builder anchor cleanup: anchors with
href="#elementor-action:...",javascript:, or bare#are unwrapped to plain text. - Internationalization: text domain is now loaded on
initand a base POT file ships in/languages/.
1.0.0
- Initial release.
