fugue

draft 1.0.0
  status draft
  title fugue — agent-facing operations
  date 2026-05-24
  license Open

---

spec fugue

  section purpose
    title Purpose
    level 1

    prose
      value
        fugue is the agent-facing layer of the family. It declares
        what an AI agent can observe about a page and what
        affordances it can invoke — without the agent ever touching
        the DOM. An AI agent should never have to guess.

  section registry-and-catalog
    title Registry and catalog
    level 1

    prose
      value
        The Registry maps ids to declarations. The Catalog is a
        navigable forest of those declarations. Together they give
        an agent a complete map of the surface it is operating.

    requirement FG-001
      level MUST
      value
        Every surface MUST be declared via a fugue+json document
        discoverable on the page (script element of type
        application/fugue+json, or external URL referenced from a
        known endpoint).

    requirement FG-002
      level MUST
      value
        Declarations MUST be parseable without executing JavaScript.
        Agents read declarations; they do not depend on runtime
        evaluation to discover the surface.

  section operations-states
    title Operations and states
    level 1

    prose
      value
        fugue distinguishes operations (what can be invoked) from
        states (what can be observed). Operations carry actor,
        target, and a gating predicate. States carry dimensions,
        each with an enumerated set of values.