A reusable calculation that exposes a plugin-transformable rendered version of a content field — the Ash-idiomatic equivalent of the WordPress the_content / Joomla onContentPrepare filter.

Add it as a calculation over the source attribute you display:

calculations do
  calculate :rendered_content, :string,
    {MishkaCmsCore.Runtime.Resources.Calculations.RenderContent, source: :content}
end

Then load :rendered_content wherever you display the content (admin grid column, JSON API field, a future public article view) instead of the raw attribute. For each record it calls "<app>:<resource>:render_<source>" with %{html: raw, record: record}; a plugin returns %{html: transformed} (shortcodes, oEmbed, related-posts, ToC, syntax-highlight, SEO injection…). With no plugin registered the raw value is returned unchanged.

It runs at display/load time, so plugins must be pure and cheap (operate on already-fetched data; never fetch a remote oEmbed here — precompute + cache, only string-substitute at render).

See MishkaInstaller.Event.Hook.