product-model

## Product model

Meridians has one graph-world substrate, one Scenario decision grammar, and several presentations.

A Domain is experienced through **three mediums**, distinguished by what is prepared and where the
initiative sits:

| Medium | The verb | Prepared in advance | Live while you are in it |
|---|---|---|---|
| **Scenario** | you *decide* | the rules and the situation | the move, and its resolution |
| **Experience** | you *read* | everything — text, images, routes | nothing; you choose among prepared paths |
| **World** | you *wander* | the state, the map, the assets | everything you say and do in it |

They are peers over one Domain, not a promotion ladder, and a Domain may support one without the others.
All three exist to deliver the same four properties the product is judged on — **consequence, meaning,
perspective, immersion** (see [positioning](../product/positioning/promise.md)) — and each is strongest at
a different one: Scenario at consequence, Experience at meaning and immersion, World at perspective.
The economics differ accordingly and the difference is load-bearing: an **Experience** is capital —
generated once, then served, so cost per reader is hosting. A **World** generates at the moment of
interaction, so its cost scales with wandering and is bounded by the instance ceiling like any other
autonomous lane. The "does not generate while you read it" property belongs to Experience and must not be
claimed for World.

- **Domain** — the world substrate: System, World, Fate, canon, branches, memory, topology, and maintained
  source material.
- **Experience** — the visual-novel medium: a prepared branch traversed as an authored reading, with
  routes, endings, POV, sprites, plates, and saves. Its unit of delivery is the **Episode**; its scaffold
  is **Script**. Specified in [the visual-novel specs](../../specs/visual-novel/README.md), not built.
- **Scenario** — the governed decision-and-resolution substrate at a branch frontier. Direct Scenario
  exposes it as a fast, abstract, currently card-led RPG.
- **Episode** — the immersive Stageplay presentation of story. A catch-up Episode embodies accepted
  history. A live Episode wraps a bounded Scenario instance so roleplay decisions can advance the branch.
- **Stageplay** — the direction, production, and interaction grammar that gives an Episode pixel-art
  staging, performance, dialogue, sound, strategic puzzles, and explanatory views. It never owns canon.
- **Factory** — the directional production workspace for reusable entity, place, moment, sound, motion,
  and interface assets. It manages identity references, appearance sets (skins), expressions, variants,
  lineage, approval, coverage, repair, and estimates over the existing asset store. It never owns entity
  facts, branch truth, latent psychology, or canonical state. Its contract lives in
  [visual-novel production](../../specs/visual-novel/production.md#12-factory--the-production-control-surface).
- **World** — the Domain as a place: a static artifact of state with a live interaction layer, held at a
  chosen **moment** and explored freeform by cursor over the map rather than read in order. It inherits
  story ontology and Factory production assets, may be tourable before it is interactive, and never
  silently advances or rewrites its source branch.
- **Moment** — the World's clock position: an `asOf` coordinate on a branch. Choosing one restores who was
  where, what had happened, and what each character could know at that point — so the same World is
  re-enterable at any point in its own history, not only at the tip.
- **Situated roleplay** — conversation with a character *inside* a moment: Domain chat bounded to what that
  character knew, where they were, and what they were living through then. The spatial and temporal
  version of chat, not a second chat product.
- **Will injection** — the input of the simulation. A Meridians world computes consequence but never
  supplies the commitment: Will enters from outside it — a reader at a fork, a seat at the card table, a
  Director steering the Program, or an autonomous agent through MCP — as a typed, attributable action on
  the canonical action boundary. Generation and exploration may propose, embody, and price a move; neither
  is Will. This is what makes a branch a divergence with an author rather than a model's continuation.
- **MCP** — the shared action interface through which human or agent Will becomes a concrete tool call.
- **Stories / Studio** — fast and deep lenses over canonical state, never alternate writers.

An **Episode posture** declares whether the passage is `catch-up` or `live`. The posture
changes where control enters, not the visual medium or authority model.

An **Episode delivery** is one prepared Stageplay presented at a declared point in an ongoing episodic
story. It may be prepared ahead, but must be revalidated against the accepted branch state before release.
Its ending may close the scene or hand the story to Will through a bounded move window.

A **story puzzle** is a consequential mechanism the player must understand well enough to direct. Its
pieces may be people, orders, timing, routes, evidence, capital, incentives, permissions, institutions,
information channels, contracts, or scarce tools. It is not an object lock or detached quiz.

An **explanatory instrument** is a bounded map, graph, ledger, dossier, board, diagram, infographic,
portrait, or cinematic view used inside an Episode to make a relation and its possible moves legible. It
is not an equal navigation mode or a second writer.

A **World origin** is the immutable branch coordinate, configuration, and asset lineage from which a World
is deployed. It also pins the active latent-model and Factory asset revisions used to interpret and render
its cast. Its activity may later persist, replay, reset, or fork; those lifecycle mechanics remain open.

A **wrapped Scenario** is a bounded Scenario instance presented through a live Episode. The player sees
roleplay, situated information, and consequential story choices; the canonical engine sees the same legal
moves, resolution, provenance, and branch write as direct Scenario.

A **seat-shaped Episode** composes shared public beats with private beats reachable by one seat's role,
knowledge, memory, permissions, and tools. Perspective is an authorization boundary before it is a camera.

**Story cultivation** is the accumulation of accepted branch history, ontology, locations, cast,
institutions, rules, evidence-grounded latent interpretations, and reusable Factory assets through direct
Scenario and Episodes until a World can be deployed.

> **Domain defines. Branch preserves. Scenario resolves. Episode embodies. World inherits and lives.**
>
> **You decide in a Scenario, read an Experience, and wander a World.**

Stageplay Episodes, Factory, and World are direction, not shipped behavior. Episode cadence, advance
preparation, multi-perspective resolution, World maturity, asset alignment, generated completion, and
lifecycle remain prototype questions. See the
[positioning boundary](../product/positioning/delivery-and-worldview.md) and the
[World concept contract](../../specs/world/README.md).

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