# V3 — Architecture (Page Index)

This directory holds the V3 (Lilith Metaverse — an embodied, multi-user world)
architecture reference, decomposed from the single
[`../V3_ARCHITECTURE.md`](../V3_ARCHITECTURE.md) hub into focused, in-depth,
code-grounded pages. The hub remains the canonical entry point and preserves
every section heading (so existing `arch§"…"` cross-references keep resolving);
each page below expands one part of the system with far richer, code-grounded
detail and an honest implemented / spec-only status. The companion feature map
lives in the [`../V3_features.md`](../V3_features.md) hub.

> **Cross-reference convention.** Page-to-page links are relative
> (`./<slug>.md`); a bare `§N` points at a section of the V3 backlog, and
> `arch§"<anchor>"` points at a named section of the
> [`../V3_ARCHITECTURE.md`](../V3_ARCHITECTURE.md) hub. Platform-foundation
> links point at the shared [`platform/`](../../platform/overview.html) space.

## Architecture landscape

```mermaid
flowchart TB
  Device[Member device network and eligibility] --> Router[Tier router and identity policy]
  Router --> UE[Native UE5 client]
  Router --> Pixel[Pixel-streaming edge and fleet]
  Router --> Web[Fallback web client]
  UE --> Gateway[Realtime gateway]
  Pixel --> Gateway
  Web --> Gateway
  Gateway --> World[Authoritative world server and room shards]
  World --> Embodiment[Avatars animation spatial audio and interaction]
  World --> Tenants[Tara Saraswati Commons and tenant plugins]
  Studio[Authoring and content pipelines] --> Tenants
  Tenants --> Data[(Tenant data content versions residency and provenance)]
  World --> Shared[V1 identity contracts audit safety and commerce]
  Data --> Operations[Observability performance security certification and launch]
  Shared --> Operations
```

The diagram is a responsibility map, not a claim that all tiers, tenants,
platforms, or regions are live. Tier routing, admission, realtime authority,
embodiment, tenant content, durable data, shared services, and operations each
produce different evidence and failure states.

Use this index to trace one experience from eligibility and tier selection
through protocol/version negotiation, gateway/world authority, tenant and
embodiment behavior, content/data/rights, shared V1 services, visible recovery,
and operational receipts. Pair the trace with the
[feature index](../features/README.md) so infrastructure readiness is evaluated
against the actual member or creator job.

Every focused architecture page appears exactly once below. The
[V3 documentation guide](../docs/README.md) supplies the truth/rollout model and
role paths, the [Lilith handbook](../docs/lilith/README.md) keeps names and
product boundaries explicit, and the [diagram atlas](../docs/diagram-atlas.md)
supplies the shared visual vocabulary. Current builds, validation, provider and
regional evidence, backlog, and release gates govern completion.

## Orientation

- [V3 Product Promise, Tiered Client Stack, and High-Level Architecture](./product-promise-and-architecture.md)
  — what V3 commits to as an embodied metaverse, and the runtime at altitude.
- [Subsystem Glossary and Project Layout](./subsystem-glossary-and-layout.md) —
  every V3 module, `libs/v3` package, and service mapped to the code that backs
  it.

## Client Tiers and Edge Delivery

- [Tier Routing and the Pixel Streaming Edge](./tier-routing-and-pixel-streaming.md)
  — how a client is routed to the right fidelity tier and the pixel-streaming
  edge.
- [Tier-1 UE5 Client: Modules, Game Feature Plugins, and Platforms](./tier1-ue5-client.md)
  — the native Unreal client, its module split, and the tenant plugin model.
- [Tier-2 Fallback Web Client and Asset Baking](./tier2-fallback-web-client.md)
  — the lower-fidelity web client and the asset-baking path that feeds it.

## Realtime Backbone

- [Lilith World Server and Realtime Gateway](./world-server-and-gateway.md) —
  the authoritative world server, the realtime gateway, and presence.
- [Multiplayer Netcode, Wire Protocol, and Physics](./netcode-protocol-and-physics.md)
  — the multiplayer netcode, the wire protocol, and shared physics/interaction.

## Avatars, Audio, and Tenant Experiences

- [Avatar, Animation & Spatial Audio](./avatar-animation-and-audio.md) — the
  MetaHuman + VRM avatar pipeline, animation, and 3D spatial audio.
- [Saraswati Stage: Music Generation & Live Performance](./saraswati-stage-pipeline.md)
  — AI music generation and the live-performance pipeline (Sequencer +
  MetaSounds).
- [Tara Live Classes, Aja Coaching & Lilith Commons](./tara-classes-aja-and-commons.md)
  — contemplative live classes, body-aware movement coaching, and the social
  commons.

## Authoring, Data, and Platform Integration

- [Authoring, Tenants & Content Pipeline](./authoring-and-content-pipeline.md) —
  the GameFeaturePlugin tenant model, the web/UE-editor authoring split, and the
  content pipeline.
- [Data Architecture, Tenancy & Residency](./data-tenancy-and-residency.md) —
  the data model, multi-tenant isolation, and per-region residency.
- [V1 Integration & Identity Bridge](./v1-integration-and-identity-bridge.md) —
  how V3 composes the V1 BFF/contracts/auth/audit and binds to shared identity.

## Trust, Rights, Commerce, and Operations

- [Persona Policy, Provenance & Rights](./persona-policy-provenance-and-rights.md)
  — persona/body policy at the avatar, content provenance, and rights/takedown.
- [Commerce & Royalties](./commerce-and-royalties.md) — the commerce model and
  creator/virtual-artist royalty settlement through the shared Aje plane.
- [Observability, Performance, Security & Launch](./observability-performance-security-and-launch.md)
  — release gates, performance budgets, build/cook/patch, security, and launch
  readiness.