# E3.M4 — SinkAndDurabilityLifecycle

## Summary

| Field | Value |
|--------|--------|
| **Module ID** | E3.M4 |
| **Epic** | [Epic 3 — Crafting Economy](../epics/epic_03_crafting_economy.md) |
| **Stage target** | Pre-production |
| **Status** | Planned (see [dependency register](module_dependency_register.md)) |

## Purpose

Item decay, consumption, repair, and other sinks that sustain demand; may integrate with market/trade flows from [E8.M3](E8_M3_PlayerTradeAndMarketplace.md).

## Responsibilities

- Track `DurabilityState`; emit `ItemSinkEvent`; apply `RepairCostRule` server-authoritatively.

## Key contracts

| Contract | Role |
|----------|------|
| `DurabilityState` | Wear and breakage. |
| `ItemSinkEvent` | Destruction/consumption audit trail. |
| `RepairCostRule` | Currency and material costs. |

## Module dependencies

- **E3.M3** — ItemizationAndInventorySchema.
- **E8.M3** — PlayerTradeAndMarketplace (epic dependency for settlement-related sinks).

## Dependents (by design)

- **E3.M5** — EconomyBalancePolicy.

## Related implementation slices

Epic 3 **Slice 4** — `item_sink`, `repair_performed`.

## Source anchors

- Master plan: [`neon_sprawl_vision.plan.md`](../../../neon_sprawl_vision.plan.md) — Epic 3.
- [Module dependency register](module_dependency_register.md)