{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://driftsys.github.io/schemas/markspec/lock/v1.json",
  "title": "MarkSpec Lock",
  "description": "Machine-managed lock file storing frozen traceability metadata by ULID.",
  "type": "object",
  "required": ["entries"],
  "additionalProperties": false,
  "properties": {
    "$schema": {
      "type": "string",
      "format": "uri",
      "description": "Schema URI for this lock file format."
    },
    "entries": {
      "type": "object",
      "description": "Entry metadata indexed by ULID.",
      "minProperties": 0,
      "additionalProperties": false,
      "patternProperties": {
        "^[0-9A-Z]{10,26}$": {
          "type": "object",
          "required": ["displayId"],
          "additionalProperties": false,
          "properties": {
            "displayId": {
              "type": "string",
              "description": "Current display ID for the ULID."
            },
            "createdAt": {
              "type": "string",
              "format": "date-time",
              "description": "Creation timestamp (explicit or inferred)."
            },
            "createdBy": {
              "type": "string",
              "description": "Creation author (explicit or inferred)."
            },
            "updatedAt": {
              "type": "string",
              "format": "date-time",
              "description": "Most recent content update timestamp."
            },
            "updatedBy": {
              "type": "string",
              "description": "Most recent content update author."
            },
            "external": {
              "type": "object",
              "description": "External tool synchronization metadata by tool key.",
              "additionalProperties": false,
              "patternProperties": {
                "^[a-z][a-z0-9-]{1,63}$": {
                  "type": "object",
                  "required": ["ref", "direction"],
                  "additionalProperties": false,
                  "properties": {
                    "ref": {
                      "type": "string",
                      "description": "External requirement identifier in the target tool."
                    },
                    "syncedAt": {
                      "type": "string",
                      "format": "date-time",
                      "description": "Timestamp of the last sync event."
                    },
                    "direction": {
                      "type": "string",
                      "enum": ["import", "export", "bidirectional"],
                      "description": "Declared sync direction for this external mapping."
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}