# Data Model: 023-clear-encounter

## Entities

### Encounter (existing — no schema changes)

The `Encounter` type is unchanged. The clear operation produces an encounter with:

| Field         | Cleared Value | Notes                          |
|---------------|---------------|--------------------------------|
| `combatants`  | `[]`          | Empty readonly array           |
| `activeIndex` | `0`           | Reset to initial               |
| `roundNumber` | `1`           | Reset to initial               |

No new fields or types are added to the data model.

## Events

### EncounterCleared (new)

| Field             | Type     | Description                                      |
|-------------------|----------|--------------------------------------------------|
| `type`            | `string` | Discriminant: `"EncounterCleared"`               |
| `combatantCount`  | `number` | Number of combatants that were removed            |

Minimal event shape — captures the count of cleared combatants for observability. No need to record the full pre-clear state (MVP baseline does not include undo).

## State Transitions

```
clearEncounter(encounter: Encounter) → ClearEncounterSuccess | DomainError

Input:  Any Encounter with combatants.length > 0
Output: { encounter: { combatants: [], activeIndex: 0, roundNumber: 1 },
          events: [EncounterCleared] }

Error:  encounter.combatants.length === 0 → DomainError("encounter-already-empty")
```

## Persistence Impact

- `saveEncounter()`: No changes — already serializes any `Encounter` to JSON.
- `loadEncounter()`: Must handle `combatants: []` case by returning the empty encounter directly instead of routing through `createEncounter()` (which rejects empty combatant arrays).