use: platform extensions

A use <extension> line in the story header admits one trusted platform extension's vocabulary (combat, state-machines) and triggers its runtime registration; a use-only story stays pure IR. (NPC vocabulary is core and always on.) Each extension brings manifest-typed trait adjectives (combatant with health 20 and skill 40, the NPC library's guard/patrol/…), and use state-machines adds the define machine … end machine block. Alongside these, the media surface (define sound/image/music … from "<file>", play sound, play ambient, show image, define channel data projections, and the client has <capability> condition) lets a story drive the browser client with no story TypeScript; text-only clients degrade cleanly. The full catalog of forms lives in the grammar reference.

story "Extensions" by "ref"
  id: ext-ref
  version: 0.0.1
  use combat

create the Guardhouse
  a room

  A low stone guardhouse.

create the sentry
  a person, combatant with health 20 and skill 40
  in the Guardhouse