{
  "date": "2026-10-24",
  "units": "integer hundredths of one fictional currency unit; divide by 100 for article figures",
  "scope": "Fixed generated records, one household, two cash locations and one card liability. Purchase-date consumption and cash-flow views differ. No interest, fees, tax, real statements, investment, overdraft or card credit balances are modeled.",
  "opening": {
    "cash": {
      "bank": 100000,
      "wallet": 10000
    },
    "card_debt": 0
  },
  "transactions": [
    {
      "id": "T1",
      "kind": "income",
      "account": "bank",
      "amount": 200000
    },
    {
      "id": "T2",
      "kind": "cash_expense",
      "account": "bank",
      "amount": 12000
    },
    {
      "id": "T3",
      "kind": "transfer",
      "source": "bank",
      "target": "wallet",
      "amount": 20000
    },
    {
      "id": "T4",
      "kind": "card_purchase",
      "amount": 6000
    },
    {
      "id": "T5",
      "kind": "card_refund",
      "amount": 1000
    },
    {
      "id": "T6",
      "kind": "card_payment",
      "account": "bank",
      "amount": 2000
    },
    {
      "id": "T7",
      "kind": "cash_expense",
      "account": "bank",
      "amount": 70000
    },
    {
      "id": "T8",
      "kind": "cash_expense",
      "account": "wallet",
      "amount": 3000
    }
  ],
  "main": {
    "opening_cash": 110000,
    "opening_net_position": 110000,
    "income": 200000,
    "consumption_expense": 90000,
    "external_cash_paid": 87000,
    "naive_expense_with_transfer_and_payment": 112000,
    "closing_cash_accounts": {
      "bank": 196000,
      "wallet": 27000
    },
    "closing_cash": 223000,
    "closing_card_debt": 3000,
    "closing_net_position": 220000,
    "rows": [
      {
        "id": "T1",
        "kind": "income",
        "account": "bank",
        "amount": 200000,
        "income": 200000,
        "consumption_expense": 0,
        "external_cash_paid": 0,
        "combined_cash_change": 200000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 300000,
          "wallet": 10000
        },
        "card_debt_after": 0
      },
      {
        "id": "T2",
        "kind": "cash_expense",
        "account": "bank",
        "amount": 12000,
        "income": 0,
        "consumption_expense": 12000,
        "external_cash_paid": 12000,
        "combined_cash_change": -12000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 288000,
          "wallet": 10000
        },
        "card_debt_after": 0
      },
      {
        "id": "T3",
        "kind": "transfer",
        "source": "bank",
        "target": "wallet",
        "amount": 20000,
        "income": 0,
        "consumption_expense": 0,
        "external_cash_paid": 0,
        "combined_cash_change": 0,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 268000,
          "wallet": 30000
        },
        "card_debt_after": 0
      },
      {
        "id": "T4",
        "kind": "card_purchase",
        "amount": 6000,
        "income": 0,
        "consumption_expense": 6000,
        "external_cash_paid": 0,
        "combined_cash_change": 0,
        "card_debt_change": 6000,
        "cash_after": {
          "bank": 268000,
          "wallet": 30000
        },
        "card_debt_after": 6000
      },
      {
        "id": "T5",
        "kind": "card_refund",
        "amount": 1000,
        "income": 0,
        "consumption_expense": -1000,
        "external_cash_paid": 0,
        "combined_cash_change": 0,
        "card_debt_change": -1000,
        "cash_after": {
          "bank": 268000,
          "wallet": 30000
        },
        "card_debt_after": 5000
      },
      {
        "id": "T6",
        "kind": "card_payment",
        "account": "bank",
        "amount": 2000,
        "income": 0,
        "consumption_expense": 0,
        "external_cash_paid": 2000,
        "combined_cash_change": -2000,
        "card_debt_change": -2000,
        "cash_after": {
          "bank": 266000,
          "wallet": 30000
        },
        "card_debt_after": 3000
      },
      {
        "id": "T7",
        "kind": "cash_expense",
        "account": "bank",
        "amount": 70000,
        "income": 0,
        "consumption_expense": 70000,
        "external_cash_paid": 70000,
        "combined_cash_change": -70000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 196000,
          "wallet": 30000
        },
        "card_debt_after": 3000
      },
      {
        "id": "T8",
        "kind": "cash_expense",
        "account": "wallet",
        "amount": 3000,
        "income": 0,
        "consumption_expense": 3000,
        "external_cash_paid": 3000,
        "combined_cash_change": -3000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 196000,
          "wallet": 27000
        },
        "card_debt_after": 3000
      }
    ]
  },
  "payment_in_next_period": {
    "opening_cash": 110000,
    "opening_net_position": 110000,
    "income": 200000,
    "consumption_expense": 90000,
    "external_cash_paid": 85000,
    "naive_expense_with_transfer_and_payment": 110000,
    "closing_cash_accounts": {
      "bank": 198000,
      "wallet": 27000
    },
    "closing_cash": 225000,
    "closing_card_debt": 5000,
    "closing_net_position": 220000,
    "rows": [
      {
        "id": "T1",
        "kind": "income",
        "account": "bank",
        "amount": 200000,
        "income": 200000,
        "consumption_expense": 0,
        "external_cash_paid": 0,
        "combined_cash_change": 200000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 300000,
          "wallet": 10000
        },
        "card_debt_after": 0
      },
      {
        "id": "T2",
        "kind": "cash_expense",
        "account": "bank",
        "amount": 12000,
        "income": 0,
        "consumption_expense": 12000,
        "external_cash_paid": 12000,
        "combined_cash_change": -12000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 288000,
          "wallet": 10000
        },
        "card_debt_after": 0
      },
      {
        "id": "T3",
        "kind": "transfer",
        "source": "bank",
        "target": "wallet",
        "amount": 20000,
        "income": 0,
        "consumption_expense": 0,
        "external_cash_paid": 0,
        "combined_cash_change": 0,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 268000,
          "wallet": 30000
        },
        "card_debt_after": 0
      },
      {
        "id": "T4",
        "kind": "card_purchase",
        "amount": 6000,
        "income": 0,
        "consumption_expense": 6000,
        "external_cash_paid": 0,
        "combined_cash_change": 0,
        "card_debt_change": 6000,
        "cash_after": {
          "bank": 268000,
          "wallet": 30000
        },
        "card_debt_after": 6000
      },
      {
        "id": "T5",
        "kind": "card_refund",
        "amount": 1000,
        "income": 0,
        "consumption_expense": -1000,
        "external_cash_paid": 0,
        "combined_cash_change": 0,
        "card_debt_change": -1000,
        "cash_after": {
          "bank": 268000,
          "wallet": 30000
        },
        "card_debt_after": 5000
      },
      {
        "id": "T7",
        "kind": "cash_expense",
        "account": "bank",
        "amount": 70000,
        "income": 0,
        "consumption_expense": 70000,
        "external_cash_paid": 70000,
        "combined_cash_change": -70000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 198000,
          "wallet": 30000
        },
        "card_debt_after": 5000
      },
      {
        "id": "T8",
        "kind": "cash_expense",
        "account": "wallet",
        "amount": 3000,
        "income": 0,
        "consumption_expense": 3000,
        "external_cash_paid": 3000,
        "combined_cash_change": -3000,
        "card_debt_change": 0,
        "cash_after": {
          "bank": 198000,
          "wallet": 27000
        },
        "card_debt_after": 5000
      }
    ]
  },
  "payment_of_opening_debt_only": {
    "opening_cash": 100000,
    "opening_net_position": 85000,
    "income": 0,
    "consumption_expense": 0,
    "external_cash_paid": 15000,
    "naive_expense_with_transfer_and_payment": 15000,
    "closing_cash_accounts": {
      "bank": 85000
    },
    "closing_cash": 85000,
    "closing_card_debt": 0,
    "closing_net_position": 85000,
    "rows": [
      {
        "id": "OLD",
        "kind": "card_payment",
        "account": "bank",
        "amount": 15000,
        "income": 0,
        "consumption_expense": 0,
        "external_cash_paid": 15000,
        "combined_cash_change": -15000,
        "card_debt_change": -15000,
        "cash_after": {
          "bank": 85000
        },
        "card_debt_after": 0
      }
    ]
  },
  "invalid_inputs": [
    {
      "case": "unknown_kind",
      "outcome": "rejected_as_expected",
      "reason": "unknown transaction kind"
    },
    {
      "case": "duplicate_id",
      "outcome": "rejected_as_expected",
      "reason": "missing or duplicate transaction id"
    },
    {
      "case": "negative_amount",
      "outcome": "rejected_as_expected",
      "reason": "amount must be a positive integer in minor units"
    },
    {
      "case": "fractional_amount",
      "outcome": "rejected_as_expected",
      "reason": "amount must be a positive integer in minor units"
    },
    {
      "case": "unknown_account",
      "outcome": "rejected_as_expected",
      "reason": "unknown cash account"
    },
    {
      "case": "same_account_transfer",
      "outcome": "rejected_as_expected",
      "reason": "transfer must connect two different known cash accounts"
    },
    {
      "case": "card_overpayment",
      "outcome": "rejected_as_expected",
      "reason": "this example excludes cash overdrafts and card credit balances"
    },
    {
      "case": "missing_amount",
      "outcome": "rejected_as_expected",
      "reason": "amount must be a positive integer in minor units"
    }
  ]
}