# D&D Combat-Turn Artifact Contract

This document defines the durable artifact, serialization, extraction, and
candidate-validation boundaries for D&D combat turns. Normalization and a
selectable production pipeline lane are not part of this contract yet.

## Artifact identity

| Property | Value |
| --- | --- |
| Artifact kind | `dnd/combat-turn-list` |
| Schema ID | `notarius.dnd.combat_turns` |
| Schema name | `notarius_dnd_combat_turns_v1` |
| Schema version | `v1` |
| Media type | `application/json` |

The top-level JSON object contains the required `combat_turns` array, which
may be empty. Every object rejects unknown fields.

## JSON shape

Each combat turn contains these required fields:

| Field | Shape |
| --- | --- |
| `actor` | Non-empty string. |
| `turn_kind` | One of `turn`, `reaction`, `legendary_action`, `lair_action`, or `other`. |
| `round` | Required JSON field containing a positive integer or `null`. |
| `actions` | Required array with at least one action. |
| `summary` | Non-empty string. |
| `source_refs` | Required array with at least one source reference. |

Each action contains these required fields:

| Field | Shape |
| --- | --- |
| `category` | One of `attack`, `spell`, `movement`, `item`, `ability_check`, `saving_throw`, `condition`, or `other`. |
| `declaration` | Non-empty string describing what was declared. |
| `targets` | Required array of strings; the array may be empty, but entries may not be empty. |
| `resolution` | Required JSON field containing a non-empty string or `null`. |

Source references use the shared source-reference shape:

```json
{
  "source_id": "session-alpha",
  "start_unit_id": 1,
  "end_unit_id": 2
}
```

`source_id` must be non-empty and both unit IDs must be positive integers. The
codec does not resolve references against a source document or enforce source
range ordering; those checks belong to the later source-reference validation
boundary.

## Codec behavior

The codec exposes two representations of the same typed artifact:

- Candidate encode/decode preserves invalid enum values, nullable values,
  required-array presence, required strings, targets, and source references so
  later validators can report them. Candidate decoding still requires valid
  JSON, one JSON value, known fields, and the explicitly present `round` and
  `resolution` keys; `null` is distinct from a missing key.
- Approved encode/decode enforces the structural rules in this contract.

The codec owns the durable JSON Schema, whose object layers all set
`additionalProperties` to `false`. Codec metadata contains only
`combat_turn_count`.

The maintained compact fixture is
`internal/modules/dnd/codec/combatturns/testdata/dnd_combat_turns.v1.json`.

## Extraction boundary

The standalone extractor uses these identities:

| Property | Value |
| --- | --- |
| Extractor key | `dnd/combat-turns` |
| Capability | `dnd.combat_turns` |
| Prompt ID | `dnd.combat_turns` |
| Prompt version | `v1` |
| Private response-schema key | `dnd_combat_turns_llm` |
| Private response-schema ID | `notarius.dnd.combat_turns.llm` |
| Default profile | `gemini-2-flash` |

It requires `chunks` and `source.transcript`, accepts no options, and makes one
structured completion for each supplied chunk. The prompt receives the
chunk-scoped transcript plus the existing `players`, `party`, and `glossary`
inputs, and optionally the deprecated `roster` reference through the shared
party mapping. The optional `npcs` reference is an approved normalized NPC
artifact used only for identity grounding; it never supplies combat evidence.

The private response shape is the same as the durable turn/action shape except
that source references contain only `start_unit_id` and `end_unit_id`. The
extractor assigns the current source ID, removes exact duplicate ranges, and
stable-sorts turns by the earliest valid source-document position. Numeric unit
IDs are identifiers; source-document slice position determines chronology.
Malformed candidate fields remain in the typed result for deterministic
validators to report.

## Deterministic candidate validation

The standalone validator keys are:

| Validator | Responsibility |
| --- | --- |
| `extract/dnd/combat-turns/shape` | Required arrays, strings, nullable fields, positive rounds, and supported enum values. |
| `extract/dnd/combat-turns/source_refs` | Source identity, source-unit existence, and range order through the source document. |
| `extract/dnd/combat-turns/source_relatedness` | At most one advisory warning per turn when the actor or declared action is not related to cited transcript text. |

Source-reference and relatedness validators defer malformed shape to the shape
validator. Relatedness also defers when any cited source range is invalid. It
combines overlapping cited ranges once in document order, compares actors with
the shared Unicode-aware NPC identity policy, and checks declaration tokens of
at least four Unicode code points against complete cited-text tokens. Targets
are not checked deterministically.

The extractor and validators are package-complete but are not registered by the
production D&D family registrar yet. Normalization, production composition,
and selectable configuration are defined when implemented.