gamedev-the-steward/docs/ARCHITECTURE_OVERVIEW.md

# The Steward — Architecture Overview

This project is organized around gameplay ownership, not scene-tree location.
Serializable simulation records are authoritative; loaded Godot nodes present
that state and contribute active-world facts such as positions and navigation
results.

## Runtime flow

```text
SimulationClock
    -> SimulationManager orchestrates one deterministic tick
        -> SimulationPopulationView indexes all/living/starving NPCs by stable ID
        -> ActionExecutionSystem advances needs and work
        -> VillageOpportunitySystem re-derives the current capable helper
        -> ActionSelectionSystem chooses an action
        -> ActionTargetResolver resolves a stable target ID
        -> VillageEconomy performs inventory/storage transactions
        -> AnimalCareSystem advances animal needs and composes feeding
        -> SimulationEventLog records completed facts
        -> EventKnowledgeSystem records, ranks, transfers, and retains bounded knowledge
        -> RelationshipSystem applies evidence-gated social consequences
        -> VillageOpportunitySystem projects one known unresolved need
    -> WorldViewManager presents travel, NPC state, and world-state cues
        -> ActiveWorldAdapter supplies loaded-world positions/capacity
            -> LoadedResourceSpatialIndex bounds finite-anchor discovery
        -> NpcVisual performs local navigation, animation, and transient reactions
        -> PantryStockVisual derives physical stock arrangement from storage state
```

`SimulationManager` is the scene-tree façade for the simulation. It owns the
tick lifecycle, authoritative NPC/village/resource records, reservations, and
the signals consumed by presentation. Focused collaborators own rules that
would otherwise obscure that lifecycle:

- `simulation/actions/` owns selection, progress, and target resolution;
- `simulation/economy/VillageEconomy.gd` owns storage/inventory transactions
  and keeps village resource summaries synchronized;
- `simulation/animals/AnimalCareSystem.gd` owns animal records, hunger
  advancement, loaded binding, feed reservations, and the exact conserved
  pantry-to-animal operation used by NPCs and the player;
- `simulation/events/SimulationEventLog.gd` owns ordered event identity,
  history queries, and rate calculations;
- `simulation/knowledge/EventKnowledgeSystem.gd` owns per-NPC references to
  known objective events, immutable acquisition provenance, proximity witnesses
  at record time, one-hop direct fact transfer, and deterministic recent-fact
  retention/importance ranking. It can place the active opportunity trigger
  first without weakening its direct-source or one-hop checks;
- `simulation/relationships/RelationshipSystem.gd` owns directed relationship
  queries, event-driven trust changes, and deterministic social tie-breaking;
- `simulation/population/SimulationPopulationView.gd` owns a transient derived
  all/living/starving stable-ID index. The manager rebuilds it once at the tick
  boundary and refreshes it after each interleaved NPC update; relationship and
  action queries may read it, but it never enters save records;
- `simulation/opportunities/VillageOpportunitySystem.gd` observes immutable
  event references plus current NPC/storage state, then owns the bounded shared
  open/resolved/invalidated lifecycle for the proven pantry-food and blocked-
  work wood consumers. It also derives one ephemeral `OpportunityHelperResult`
  from knowledge, directed relationships, inventory, action definitions, and
  finite-resource state without changing resources or assigning tasks. The
  ordinary action selector consumes that result only for the matching idle NPC.
  When no such helper exists, it can separately derive an ephemeral
  `OpportunityPlayerResponseResult` from the real destination capacity and
  enabled player-usable finite sources;
- `simulation/persistence/` owns save-slot file safety;
- `simulation/state/` owns versioned serialized record contracts;
- `simulation/definitions/` owns stable IDs and immutable action/profession
  definitions.

`world/resource_nodes/LoadedResourceSpatialIndex.gd` is a focused disposable
acceleration structure owned by `ActiveWorldAdapter`. It indexes loaded
interaction positions by action and horizontal cell, plus authoritative
metadata bounds copied at bind time. It does not own amounts, enabled state,
reservations, or persistence. `ResourceNode` enter/exit, bind, and transform
notifications keep it synchronized with the loaded presentation lifecycle.
Resource anchors may be nested inside authored presentation clusters: runtime
discovery uses their stable IDs and registration lifecycle, never a parent
path. Decorative siblings without a `ResourceNode` remain outside the index
and simulation state.

Outside the runtime lifecycle, `simulation/benchmark/` owns reusable,
schema-valid workload fixtures. CLI tools and headless scenarios consume those
fixtures; production simulation does not depend on benchmark code.

The manager deliberately remains a façade instead of being split into a
collection of scene-tree manager nodes. A new collaborator is justified when
one cohesive rule set has several real consumers or makes the tick lifecycle
hard to read.

## Folder ownership

| Path | Responsibility |
| --- | --- |
| `simulation/` | Headless-capable orchestration and core models |
| `simulation/actions/` | Action decisions, execution, and target queries |
| `simulation/animals/` | Animal lifecycle, target claims, and feeding transactions |
| `simulation/economy/` | Authoritative inventory and storage transactions |
| `simulation/events/` | Immutable event history and derived event queries |
| `simulation/knowledge/` | Per-NPC knowledge of objective event IDs |
| `simulation/relationships/` | Directed social consequences and relationship queries |
| `simulation/population/` | Transient per-tick population query indexes |
| `simulation/opportunities/` | Knowledge-gated unresolved-condition projections |
| `simulation/state/` | Versioned, serializable mutable records |
| `simulation/definitions/` | Stable IDs and immutable gameplay definitions |
| `simulation/persistence/` | Validated local save-file storage |
| `simulation/benchmark/` | Reproducible simulation and loaded-world query workloads |
| `world/` | Loaded-world interaction geometry and presentation adapters |
| `world/animals/` | Animal presentation binding and interaction geometry |
| `world/resource_nodes/` | Finite resource presentation and disposable loaded-anchor index |
| `world/storage/` | Storage interaction geometry, never stored quantities |
| `world/activity/` | Rest/study/patrol interaction sites and capacity facts |
| `player/` | Player input, camera, and active NPC presentation |
| `tests/` | Deterministic headless gameplay scenarios |

Top-level core model scripts keep their stable paths because Godot's global
class cache records `class_name` locations. Moving them solely for cosmetic
nesting can break editor and headless startup for existing workspaces without
improving ownership.

## Dependency rules

- Simulation code must run without `main.tscn` or loaded world nodes.
- Persistent references are stable IDs, never `Node`, `NodePath`, or scene
  ownership.
- Presentation may report facts and submit commands; it does not choose NPC
  actions or own resource, storage, inventory, event, knowledge, relationship,
  opportunity, or reservation state.
- Inspector history is a read-only façade query over objective events and
  retained knowledge. Opportunity presentation is likewise query-only.
  Relationship cues, interested-villager concern, physical pantry stock, and
  refill feedback consume authoritative state or state-change signals and are
  intentionally absent from saves and checksums. The transient village-whisper
  HUD likewise formats need, player route, transfer, response, and resolution
  signals without owning them. It drops the player route when a capable helper
  emerges. Stable visuals are rebuilt from state after restore; transient
  reactions are not replayed.
- Resource changes go through `ResourceStateRecord`, NPC inventory, and
  `VillageEconomy`; `village.food` and `village.wood` are synchronized views.
- Animal identity, position, hunger, last feed tick, and reservation live in
  `AnimalStateRecord`. `AnimalNode` binds that state and contributes only its
  loaded interaction point. Animal candidates are currently scanned linearly;
  they do not enter the resource grid.
- New mutable features define serialization and deterministic continuation at
  the same time as their first gameplay use. Cross-record causes use stable
  event IDs rather than object references or prose.
- Benchmark fixtures use ordinary simulation records and must round-trip
  through the current state schema. They may control workload setup, but must
  not add benchmark-only fields or branches to production saves and ticks.
- Derived population indexes are disposable acceleration structures. NPC
  records remain authoritative, and rebuilding the view after initialization,
  restore, or a tick must produce the same decisions and checksum.
- The loaded-resource grid is likewise disposable. `ResourceStateRecord`
  remains authoritative while its scene node is absent; rebuilding or
  incrementally refreshing the grid must preserve the linear resolver's exact
  score winner and stable tie order.
- Camera-local grass, ambient butterflies, water animation, smoke, and foliage
  motion are presentation only. Grass consumes bounded real actor transforms;
  it does not write NPC positions or become persistent state.
- Opportunity records reference stable NPC, storage, resource, trigger-event,
  and resolution-event IDs. Their generator may observe authoritative state
  and history, but it does not mutate the economy or command NPC behavior. The
  manager re-queries capable helpers at idle selection boundaries; any selected
  supply task then follows the ordinary persisted NPC-task and target contracts.
- Prefer one tested vertical behavior over a generic framework with no proven
  consumers.

## Where new code goes

Put a rule beside the state it governs. A relationship consequence belongs in
a focused simulation system plus serialized relationship records; its icon or
animation belongs in presentation. Add a world node only when the behavior
needs loaded-world geometry. Add a stable ID or definition when content must be
referenced across saves, scenes, or unloaded simulation.

The architectural decision and detailed contracts live in
[ADR 0001](decisions/0001-simulation-authority-boundary.md),
[the action system architecture](ACTION_SYSTEM_ARCHITECTURE.md), and
[the simulation state schema](SIMULATION_STATE_SCHEMA.md).