Systems Index: Iron & Timber — The Muster

Status: Draft
Created: 2026-09-12
Last Updated: 2026-09-12
Source Concept: design/gdd/game-concept.md

Overview

Iron & Timber is a frontier colony sim whose central mechanical claim is that "the economy IS the militia" — every unit of military capability traces back to a production decision, with no separate recruitment system. Mechanically, this means three normally-independent subsystems (economy, settler simulation, and combat) must share state tightly: the same settler who works a job also becomes a defender, the same smith output that becomes a tool could have become a weapon, and the same stockpile that feeds the population also arms it.

The systems below decompose into four families: Foundation (time, camera, resources — nothing game-specific yet), Economy (production chains, recipes, the dual-purpose output split, the armory), Settler Simulation (job assignment, pathfinding, role switching — the architecture research's central concern), and Threat (raiders, telegraphed danger, the muster itself, and combat resolution). The MVP's single hypothesis — does the displaced-cost muster feel weighty? — requires nearly all of these families to exist in at least a minimal form, which is why the MVP tier is large (18 systems) relative to the concept doc's short "Required for MVP" list (5 items). Short feature lists always imply more supporting systems once dependencies are made explicit; this is normal, not scope creep.

Systems Enumeration

Categories

Priority Tiers

Dependency Map

Foundation Layer (no dependencies)

• Camera & Input — an isometric city-builder's most basic interaction layer; nothing else is playable without it
• Calendar/Time System — the clock everything else's timing reads from; a bottleneck system
• Resource/Stockpile System — the ledger every economic decision routes through; a bottleneck system

Core Layer (depends on foundation)

• Pathfinding & Movement — depends on: Camera & Input
• Building Placement & Construction — depends on: Camera & Input, Resource/Stockpile System
• Settler Job Assignment — depends on: Pathfinding & Movement, Resource/Stockpile System (a bottleneck system — see High-Risk Systems)

Feature Layer (depends on core)

• Recipe/Crafting System — depends on: Resource/Stockpile System, Building Placement & Construction
• Production Chains — depends on: Recipe/Crafting System, Settler Job Assignment, Resource/Stockpile System
• Dual-Purpose Output System — depends on: Recipe/Crafting System, Production Chains
• Armory / Gear Storage — depends on: Dual-Purpose Output System, Resource/Stockpile System
• Settler Role State Machine — depends on: Settler Job Assignment, Armory / Gear Storage
• Enemy/Raider AI — depends on: Pathfinding & Movement, Calendar/Time System
• Telegraphed Threat System — depends on: Calendar/Time System, Enemy/Raider AI
• Settler Needs — Food (Vertical Slice) — depends on: Production Chains, Calendar/Time System
• Save/Load (Alpha) — depends on: all stateful systems above

Presentation Layer (depends on features)

• The Muster — depends on: Settler Role State Machine, Armory / Gear Storage, Telegraphed Threat System
• Alarm/Notification System — depends on: The Muster, Telegraphed Threat System
• Combat Resolution — depends on: The Muster, Enemy/Raider AI
• Threat Forecasting UI — depends on: Telegraphed Threat System, Calendar/Time System
• Armory/HUD Readout — depends on: Armory / Gear Storage, Dual-Purpose Output System

Polish Layer (depends on everything)

• Seasonal Cycle (Vertical Slice) — depends on: Calendar/Time System, Production Chains, Telegraphed Threat System. Functionally a content/tuning layer over the Calendar (different rates, timing, and visuals per season) rather than a new mechanical system.

Recommended Design Order

[Effort estimates: S = 1 session, M = 2-3 sessions, L = 4+ sessions. A "session" is one focused design conversation producing a complete GDD.]

Circular Dependencies

None found — the dependency graph is a clean DAG.

One tight cluster worth designing together, though not circular: The Muster, Settler Role State Machine, and Armory / Gear Storage all reference each other conceptually — a settler's available role depends on armory stock, which is read by the muster, which changes settler roles. Data flows one direction per tick (Armory → Muster → Settler Role), so there is no cycle, but these three GDDs will cross-reference each other constantly. Consider drafting them in the same session even though they're listed as three separate design-order steps.

High-Risk Systems

Progress Tracker

Next Steps

• [x] Review and approve this systems enumeration
• [ ] Design MVP-tier systems first (use /design-system [system-name])
• [ ] Run /design-review on each completed GDD
• [ ] Run /gate-check pre-production when MVP systems are designed
• [ ] Validate the highest-risk systems with /vertical-slice before committing to Production
• [ ] Consider /prototype muster-mechanic before writing GDDs for systems #14 (The Muster), #9 (Dual-Purpose Output), and #16 (Combat Resolution) — these three carry the MVP's design risk