get_spending_trends

What it does

Spending per category, month by month, over the last N months.

Use it for “is my grocery spending going up?” or to compare months. The result maps each category name to its spending month by month, oldest first, as a positive number in currency units. For a single month use get_category_balances or get_budget_vs_actual; for the months ahead, forecast_balance. One YNAB request for the list of months, then one per month; changes nothing.

Behaviour


Kind	read-only
Confirmation	no
Undo	no
Idempotent	yes
YNAB requests	4 for the example below, on a cold cache

Parameters

Name	Type	Required	Default	Description
`plan_id`	string	yes	—	YNAB plan id or ‘last-used’.
`months_count`	integer	no	`3`	Number of past months to include, 1 to 24 (default 3).

Returns

object

Example

Arguments:

{
  "plan_id": "demo-budget",
  "months_count": 3
}

Answer on the demo budget:

{
  "Rent": [
    {
      "month": "2026-07-01",
      "amount": 950.0
    },
    {
      "month": "2026-08-01",
      "amount": 950.0
    },
    {
      "month": "2026-09-01",
      "amount": 950.0
    }
  ],
  "Electricity": [
    {
      "month": "2026-07-01",
      "amount": 64.2
    },
    {
      "month": "2026-08-01",
      "amount": 64.2
    },
    {
      "month": "2026-09-01",
      "amount": 64.2
    }
  ],
  "Internet": [
    {
      "month": "2026-07-01",
      "amount": 29.99
    },
    {
      "month": "2026-08-01",
      "amount": 29.99
    },
    {
      "month": "2026-09-01",
      "amount": 29.99
    }
  ],
  "Phone": [
    {
      "month": "2026-07-01",
      "amount": 19.99
    },
    {
      "month": "2026-08-01",
      "amount": 19.99
    },
    {
      "month": "2026-09-01",
      "amount": 19.99
    }
  ],
  "Groceries": [
    {
      "month": "2026-07-01",
      "amount": 172.89
    },
    {
      "month": "2026-08-01",
      "amount": 192.51
    },
    {
      "month": "2026-09-01",
      "amount": 0.0
    }
  ],
  "Restaurants": [
    {
      "month": "2026-07-01",
      "amount": 61.5
    },
    {
      "month": "2026-08-01",
      "amount": 89.1
    },
    {
      "month": "2026-09-01",
      "amount": 142.5
    }
  ],
  "Transport": [
    {
      "month": "2026-07-01",
      "amount": 45.0
    },
    {
      "month": "2026-08-01",
      "amount": 45.0
    },
    {
      "month": "2026-09-01",
      "amount": 0.0
    }
  ],
  "Tennis": [
    {
      "month": "2026-07-01",
      "amount": 22.0
    },
    {
      "month": "2026-08-01",
      "amount": 22.0
    },
    {
      "month": "2026-09-01",
      "amount": 0.0
    }
  ],
  "Subscriptions": [
    {
      "month": "2026-07-01",
      "amount": 13.49
    },
    {
      "month": "2026-08-01",
      "amount": 13.49
    },
    {
      "month": "2026-09-01",
      "amount": 0.0
    }
  ],
  "Holidays": [
    {
      "month": "2026-07-01",
      "amount": 0.0
    },
    {
      "month": "2026-08-01",
      "amount": 0.0
    },
    {
      "month": "2026-09-01",
      "amount": 0.0
    }
  ]
}

Errors

This tool raises no error of its own; YNAB’s errors come back as Error calling tool '<tool>': YNAB <status>: <detail>.