Head fields

What a page’s or a site’s head may be told to say, and where each field may be set. Served over MCP as vizitka://docs/meta, and by describe_vocabulary with topic=meta.

Field	Set on	Type	What it says
description	a page or the site	string	One or two sentences about the page, shown under its title in a search result and on a shared link. Set at site level it describes the whole site.
keywords	a page or the site	string	Comma-separated words. Search engines have long ignored these; they are here because some other tools still read them.
image	a page	key	The picture a shared link shows, as the key of a file on this site’s disk (list_files). The site’s own social image is used for a page that names none.
canonical	a page	url	The address this page is a copy of, as a full https URL. Only for a page published somewhere else first — every page canonicalises to its own address without this.
noindex	a page or the site	boolean	Ask search engines to leave this out of their index. Set at site level it hides the whole site, which is for a site that is not ready to be found.
author	the site	string	Who made the site — usually the owner’s own name.
theme_color	the site	string	The colour a phone browser paints its chrome with, as a CSS colour (“#101010”).
twitter	the site	string	The site’s X handle, with the @ (“@mirahalden”). It is what an X card credits.
page_fades	a page or the site	boolean	Fade from one page of the site into the next instead of cutting. Off unless set, and a page’s own value overrides the site’s.
morph_refreshes	a page or the site	boolean	Redraw a page that answers with itself, such as a form’s thanks, in place and at the same scroll position. Off unless set, and it asks things of the site’s own scripts (vzk/javascript).