notarius/docs/integrations/dnd-spell-catalog-overlays.md

D&D Spell-Catalog Overlay Contract

This document defines the JSON format accepted by the D&D spell catalog resolver. An overlay supplies campaign-specific spell names and aliases for recognition. It does not supply spell rules, levels, classes, effects, or source evidence.

Shape

An overlay bundle has this shape:

{
  "schema_version": "notarius.dnd.spell-catalog-overlay.v1",
  "catalogs": [
    {
      "id": "campaign.example",
      "ruleset": "dnd-5e-2014",
      "source": {
        "title": "Example campaign spells",
        "version": "1",
        "url": "",
        "license": ""
      },
      "spells": [
        {
          "name": "Aegis of Emberfall",
          "aliases": ["Emberfall Aegis"]
        }
      ]
    }
  ]
}

The top-level schema_version and catalogs fields are required. The schema version must be exactly notarius.dnd.spell-catalog-overlay.v1, and at least one catalog is required. Catalogs require a unique, non-empty, trimmed id, the exact dnd-5e-2014 ruleset, a source, and a non-empty spells array.

source.title is required and must be non-empty and trimmed. source.version, source.url, and source.license are optional strings and may be empty. Each spell requires a non-empty, trimmed name. aliases may be omitted or may be an array of trimmed, non-empty strings; JSON null is not an alias array. Overlay objects contain no other supported spell fields.

Decoding is strict: unknown fields, malformed JSON, trailing JSON values, and non-string optional source fields are rejected.

Composition

The resolver always starts with the embedded D&D 5e 2014 SRD catalog. Overlay catalogs are sorted by id before composition, so the input order does not affect the result. A new canonical name adds a recognition entry. A canonical name matching an existing canonical name augments that spell and keeps the established canonical display spelling. Repeated aliases for the same spell are idempotent.

Canonical-name display conflicts and canonical/alias or alias/alias collisions between different spells are errors, including collisions with the embedded catalog. Canonical names and aliases use the catalog's case, whitespace, and common-apostrophe normalization rules. The effective catalog returns canonical names in sorted order and produces a semantic SHA-256 digest that is stable under JSON formatting, object-key, catalog, spell, and alias reordering.