# Tyre - Project Briefing
Last updated: 2026-02-10

## Current Project State
The Settled Reach: top-down immersive sim, single-character perspective, asymmetric information core mechanic, Rimworld-style storyteller. 29 confirmed decisions, 17 discussion rounds complete. Engine selected (D-020: Godot + Rust/bevy_ecs subprocess). Vertical slice defined (D-027).

## Decisions Relevant to Your Role
- D-008: Z-levels, LOD, procedural generation - technical architecture implications
- D-010: Four architectural principles - client-server, deterministic sim, information boundaries, input events
- D-011: LOS shadowcasting implementation for fog of war
- D-012: Chunk-based map architecture for streaming and generation
- D-014: v0.1 map specification - full technical requirements
- D-015: Camera lock to character - vision cone rendering and binaural audio hookup
- D-017: Perception as observer queries - technical pattern for all perception modes
- D-018: Sound propagation system - three-range model with wall occlusion
- D-019: Top-down primary view with potential future 3D client
- D-020: Godot 4 client + Rust/bevy_ecs server via subprocess/IPC, MessagePack serialization
- D-021: Official title "The Settled Reach"

### Round 17 Decisions (Technical Architecture)
- **D-024: CombatCapability as ECS component** - Optional component triggered by combat-trained skill tag. Pattern applies to all optional systems. Follows D-017 perception mode model (capabilities as components, not monolithic state).
- **D-025: Single-ownership template model with reference links** - NPCs owned by one template, referenced by others. Reference links carry relationship metadata. Prevents lifecycle conflicts.
- **D-026: Simulation tier budgets confirmed** - Your numbers: Active (30-80 NPCs, 10-20 tps), Background (500-2K NPCs, state machines 1/game-min, 4 machines each), State-saved (~1-2KB serialized structs), Ungenerated (doesn't exist). Timestamp-based LRU eviction. bevy_ecs dynamic components for tier transitions.
- **D-027: Vertical slice systems** - Access tier system + cargo/goods system needed for smuggling ring mechanics. Two characters = ~20% more effort, no new architecture (client-server already supports multi-observer).
- **D-028: Line previewer CLI** - Weekend build. Authoring tool and regression test harness. Takes template YAML → NPC instances → trait modifiers → outputs generated line pools with metadata.

## Open Questions Assigned to You
- Q-001: Engine selection (LEAD, CRITICAL - next priority)
- Q-002: v0.1 scope definition (co-lead)
- Q-005: Prototype scale (co-lead with Gestalt, Miri)
- Q-007: Target platforms

## Current Priorities
Vertical slice technical implementation:
1. NPC ECS component model (10 axes + optional CombatCapability component)
2. Template instantiation system (single-ownership + reference links with metadata)
3. Simulation tier transitions (timestamp LRU + scope tags + bevy_ecs component add/remove)
4. Access tier system (content filtering by tier 0-3)
5. Basic cargo/goods system (for smuggling ring mechanics)
6. Line previewer CLI (weekend build — YAML templates → trait-modified line pools)

**Future flag:** Base builder DLC requires data model stub now: `modifications: Vec<Modification>` on relevant entities. Add to schema early.

## Key Documents
- DECISIONS.md - all confirmed decisions
- DISCUSSION.md - active discussion round
- docs/discussions/ - archived rounds
- TEAM.md - team roster