Architecture

Per proposal §14: a Fabric modpack built around a custom core, split into feature mods "where it makes sense." Separation criteria: a system becomes its own mod when it (a) owns a distinct slice of gameplay, (b) can be developed/tested in relative isolation, and (c) could in principle be toggled off. Shared plumbing lives in core so modules don't depend on each other sideways.

1.1 The module roster

Mod (id)	Owns	Depends on
Alone: Core (alone-core)	Config, networking, registry helpers, player-data attachments, the accelerated-tick engine (work sessions + sleep, proposal §1.4/§8.3), shared events, HUD framework. Currently also hosts the first grounding rule.	—
Alone: Body (alone-body)	Survival meters (hunger/thirst/temperature/stamina/sleep) + the condition panel that replaces the health bar (§1). The spine everything hooks into.	Core
Alone: Fire (alone-fire)	Friction fire, ember carrying, furnace/kiln tiers, charcoal clamp, the ash economy (§3).	Core
Alone: Water (alone-water)	Vessel ladder + contamination + hot-rock boiling; finite/flowing water rules (§2).	Core, Fire
Alone: Table (alone-food)	Nutrition groups & food fatigue, spoilage/freshness, preservation, scent emission (§4).	Core, Body, Fire
Alone: Wild (alone-wild)	Scent-driven wildlife AI, bears/predators, deer/rabbit populations, hunting/tracking/persistence, butchering, structure-scoped spawning, insects (§7).	Core, Table, Body
Alone: Craft (alone-craft)	Knapping, no punching trees, timed stationary crafting, tool/material ladder, masterwork quality, sharpening, combat-as-conditions, skill-by-doing (§8).	Core, Body
Alone: Ground (alone-build)	Weight & carry tiers + movement penalties, stick-block family w/ degradation, shelter quality, tree felling + age states, gravity/support, fire spread (§5).	Core, Body
Alone: Road (alone-transport)	Backpack, wheelbarrow, travois, rafts/boats, pack animals, horse+cart w/ emergent roads, rail gating (§6).	Core, Ground
Alone: World (alone-world)	Seasons, weather-with-teeth, biome strategies, navigation (no coords, compass, hand-drawn maps, celestial) (§10).	Core, Body
Alone: Relics (alone-loot)	Structure-scoped loot, relics, rationalized mob drops, redstone gating, villager barter/reputation (§7.4, §12).	Core, Wild

Architecture update (2026-07-08): the survival body — meters, conditions, the condition panel, and the shared tick engine — is being built inside alone-core, not as a separate Alone: Body mod. Rationale: these systems are the spine that every content mod (food, fire, water, wild, …) hooks into, and they interlock too tightly to split cleanly. Keeping them in core means content mods depend on one thing (core) instead of a web of body sub-mods. Conditions (sickness) and SurvivalMeters (stamina) are the first pieces.

Datapack territory (per §14), layered on top rather than as mods: loot tables, food-poison odds, break-time multipliers, tag edits.

1.2 Dependency shape

                         alone-core
        ┌──────────┬─────────┼──────────┬──────────┬─────────┐
   alone-body  alone-fire  alone-craft  alone-ground alone-world (…)
        │          │           │            │
   alone-water ────┘      (combat/tools) (weight/felling)
        │
   alone-food ── alone-wild ── alone-loot ── alone-road

Core is the only thing everyone imports. Modules never depend sideways on a peer's internals — only on core's shared API (data attachments, events, the tick engine).

1.3 Repo layout (Gradle multi-project monorepo)

alone/
├── flake.nix                 # NixOS dev environment (JDK 25, gradle, graphics libs, Prism)
├── settings.gradle           # declares each module as a Gradle subproject
├── build.gradle              # shared Loom/Fabric config applied to every module
├── gradle.properties         # pinned versions (MC 26.2, loader, fabric-api)
├── modules/
│   └── core/                 # ← Alone: Core (the only module today)
│       ├── build.gradle
│       └── src/main/{java,resources}
│   └── body/ …               # future modules drop in here; one `include` line, no root changes
├── proposal.md
└── implementation-plan.md

One nix develop, one Gradle build, each module compiles to its own jar. Adding a module = mkdir modules/<name>, add one include line, done.