{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://oco-adam.github.io/specgraph/schemas/graph.schema.json",
  "title": "Spec Graph Index",
  "description": "Entry-point index for a Spec Graph. Lists all nodes and their file paths. Edges are defined inside each node file.",
  "type": "object",
  "required": ["specgraphVersion", "nodes"],
  "additionalProperties": false,
  "properties": {
    "$schema": {
      "type": "string",
      "description": "Path or URL to this schema for editor validation."
    },
    "specgraphVersion": {
      "type": "string",
      "description": "Spec Graph schema version for this graph.",
      "pattern": "^\\d+\\.\\d+\\.\\d+(-[0-9A-Za-z-.]+)?$",
      "examples": ["1.0.0", "1.0.0-beta.1"]
    },
    "root": {
      "type": "string",
      "description": "Optional root node ID (commonly a feature or equivalence_contract node).",
      "minLength": 1,
      "maxLength": 80
    },
    "nodeSearchPaths": {
      "type": "array",
      "description": "Optional additional directories to scan for nodes.",
      "items": { "$ref": "#/$defs/relativePath" }
    },
    "nodes": {
      "type": "array",
      "description": "Canonical list of nodes and their file paths (relative to graph.json).",
      "minItems": 1,
      "items": { "$ref": "#/$defs/nodeRef" }
    },
    "defaults": {
      "type": "object",
      "description": "Optional default values for tooling.",
      "additionalProperties": true
    }
  },
  "$defs": {
    "relativePath": {
      "type": "string",
      "description": "Relative POSIX-style path. No absolute paths or parent traversal.",
      "pattern": "^(?!/)(?!.*\\.{2}/)[A-Za-z0-9._/-]+\\.json$"
    },
    "sha256": {
      "type": "string",
      "description": "Hex-encoded SHA-256 digest.",
      "pattern": "^[A-Fa-f0-9]{64}$"
    },
    "nodeRef": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "path"],
      "properties": {
        "id": {
          "type": "string",
          "description": "Node ID (must match the node file's id field).",
          "minLength": 1,
          "maxLength": 80,
          "pattern": "^[A-Z][A-Z0-9-]{0,79}$"
        },
        "path": {
          "$ref": "#/$defs/relativePath",
          "description": "Relative path to the node file."
        },
        "sha256": {
          "$ref": "#/$defs/sha256",
          "description": "Optional content hash for tamper detection."
        },
        "expectedType": {
          "type": "string",
          "description": "Optional expected node type for quick validation.",
          "minLength": 1
        }
      }
    }
  }
}