Recurring Markdown and /llms.txt failures.
Markdown URL problems
Does the post URL return HTML when published?
Does the post type support prc-markdown-for-agents?
Publish first
Markdown endpoints only serve published posts that resolve via url_to_postid().
Opt the post type in
Call add_post_type_support( $type, 'prc-markdown-for-agents' ) on init, then flush permalinks if rewrites changed.
Check conversion next
If the URL still 404s, confirm rewrite rules and VIP cache. If Markdown is thin, register a block callback.
This answer needs a valid destination.
Edit the block and connect this answer to another question or outcome.
.md URLs return 404
Cause: Post type lacks prc-markdown-for-agents support, or the post is not published.
Fix: Opt the type in on init and confirm publish status.
Canonical URL ignores Accept: text/markdown
Cause: Accept negotiation is disabled by default.
Fix: Agents should use rel="alternate" → .md / /markdown. Re-enable only after PRC-466 is resolved:
define( 'PRC_MARKDOWN_FOR_AGENTS_ENABLE_ACCEPT_NEGOTIATION', true );Purge VIP edge cache after enabling.
Authors show “Pew Research Center”
Cause: prc-staff-bylines inactive or no bylines; WP user fallback empty.
Fix: Activate bylines and assign them, or filter prc_markdown_for_agents_authors.
HTML conversion strips formatting
Cause: Generic HTML → Markdown fallback cannot parse some structures.
Fix: Register a block-specific callback via Block_Markdown_Registry::register().