{
  "name": "Contract",
  "description": "A vendor contract in the Tropic procurement platform",
  "fields": [
    { "name": "id", "type": "string", "description": "Unique identifier", "required": true },
    { "name": "name", "type": "string", "description": "Contract name", "required": true },
    { "name": "supplier_id", "type": "string", "description": "Associated supplier ID", "required": false },
    { "name": "supplier_name", "type": "string", "description": "Supplier name (denormalized)", "required": false },
    { "name": "status", "type": "enum[active,expired,pending,cancelled]", "description": "Contract lifecycle status", "required": true },
    { "name": "start_date", "type": "date", "description": "Contract start date", "required": true },
    { "name": "end_date", "type": "date", "description": "Contract end date", "required": false },
    { "name": "renewal_date", "type": "date", "description": "Renewal tracking date", "required": false },
    { "name": "total_value", "type": "number", "description": "Total contract value", "required": false },
    { "name": "currency", "type": "string", "description": "ISO 4217 currency code", "required": false, "default": "USD" },
    { "name": "owner_id", "type": "string", "description": "Owning user ID", "required": false },
    { "name": "documents", "type": "array[Document]", "description": "Attached documents", "required": false },
    { "name": "created_at", "type": "datetime", "description": "Creation timestamp", "required": false },
    { "name": "updated_at", "type": "datetime", "description": "Last updated timestamp", "required": false }
  ],
  "nested": {
    "Document": {
      "fields": [
        { "name": "id", "type": "string", "required": true },
        { "name": "name", "type": "string", "required": true },
        { "name": "url", "type": "uri", "required": false }
      ]
    }
  }
}