SCOPE.md

Scope

What Multivoid synchronises between peers, and what it deliberately does not. This is principle 5 in practice: anything not listed here is not synced, and a new item is classified against the rules at the bottom before a line of code is written for it. When a decision changes, its row changes, in the commit that ships the change.

Synced

System	What is synced	Who owns it
Players	position and pose, the ragdoll and faint display state, health, food and sleep as fractions, the held item, skins, nameplate visibility, nickname colour; enemy hits delivered to the hit peer; death runs natively and the level travel is refused so the world survives	each peer computes its own vitals and death; the host delivers enemy hits
Chat and the event feed	text chat; join, leave and error lines	the host relays chat; each machine surfaces its own transport errors
Voice	3D positional voice	each peer
Master server and browser	an opt-in listing of the host's game, the update check, signaling for NAT traversal	the host opts in per session; the master is external infrastructure
Physics props	pickup, drag, throw and drop; per-grab authority; an identity that survives saves and rejoins; world-to-inventory and inventory-to-world transitions	the holder while held; the host owns everything at rest
Piles and trash	the whole collection loop: piles, clumps, carrying, depositing	the host
NPCs and creatures	pose, spawn and despawn, the kerfur prop-to-NPC cycle; enemies target every peer and a pursuit can switch targets between peers; creatures whose AI reads the local player are owned per peer and visible to all	the host, except the per-peer owned creatures
Doors, lights and devices	doors, light switches and light groups, keypads, power panels, the garage, appliances, locker lids, windows, grime, the wind turbine, containers and their contents, the delivery drone, shop orders, the coin gun and the shared balance	the host holds the state; a client sends an intent that the host performs
The signal workstation	the dish, pinging, signal catch, downloads, decoding, the playback deck, drives and racks, tapes, the physical modules, the laptop and its floppies, the meadow signal database, the signal-server simulation and the notices it produces	one authority per axis: the pressing peer authors inputs, the host runs every simulation
World state	the clock, the sky, weather and lightning, fireflies, ambient spawners, the story and scheduled events, the base alarm, emails, the daily task, world props that change over time	the host; clients mirror and never roll their own randomness
Saves	the joiner boots from the host's world; the host is the only peer that saves	the host
Vehicles	the ATV: a peer that is not driving runs the vehicle's physics natively and is corrected toward the driver's pose; its condition travels; vitals, configuration and the act-as-host intents are in scope and not all built	the driver authors the pose; the host the rest
Sleep, damage and hazards	sleep state, hazard damage, the resulting vitals	the host for shared effects; each peer for its own vitals

Not synced

What	Why
Inventory contents: slot order, stack counts, what is in a pocket	per-peer and private; the UI stays responsive and each player's kit is their own. The world-side effect of a pickup or drop is synced
Unreal's built-in replication	the game's Blueprints are single-player; enabling it means editing assets, which the mod never does
Outdoor lamp posts	driven by the shared day and night cycle on every machine; they toggle in lockstep without traffic
Custom content paks and asset replication	a peer without a skin pak sees the default body, by design; nothing is downloaded from another peer
Anti-cheat	the host is trusted and is the admin; every bound and sanity check applies to clients only
Hint toasts, tutorial tips, the per-viewer HUD	local to the machine; the HUD reads shared state, it is not itself replicated

Rules for classifying a new item

1. Replicate authoritative state; re-derive the rest. Animation, physics and rendering are computed by each machine's own engine from the streamed state.
2. The whole map syncs. There is no area-of-interest culling; bandwidth is gated by whether an entity is active, never by distance.
3. The host rolls shared-world randomness. A client never rolls a shared outcome.
4. A client acts by intent. A discrete, persistent, shared-world change made by a client is an intent the host performs, and the intent names what, never what it costs.
5. Every lane answers the late join. A peer that joins mid-event, mid-download or mid-drive sees the current state; a lane is not done until that answer exists.
6. Per-peer things stay per-peer. Own vitals, own inventory, own view.
7. Four players, about a hundred active entities is the scale everything is sized for.