{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Exact ad ID string",
  "type": "object",
  "required": ["ad_id"],
  "properties": {
    "ad_id": {
      "type": "string",
      "pattern": "^[0-9]+$",
      "description": "Carry the exact source identifier as text. Validate the source string before numeric conversion."
    }
  },
  "additionalProperties": true
}