{
 "system": "You are a careful bookkeeping and admin assistant for a UK small business. Be accurate. UK standard VAT rate is 20%.",
 "task": "Here is our business bank account export for September/early October 2026. Opening balance on 2026-09-07 before these transactions: \u00a34210.55.\n\ndate,description,category,amount_gbp\n2026-09-07,Card takings,Sales,1840.20\n2026-09-07,Rent - Unit 4,Rent,-1250.00\n2026-09-08,Wholesale order Harrogate,Sales,960.00\n2026-09-09,Ceramic supplies,Stock,-712.35\n2026-09-11,Card takings,Sales,1523.75\n2026-09-12,Electricity,Utilities,-184.60\n2026-09-14,Card takings,Sales,1210.40\n2026-09-15,Wages,Payroll,-2400.00\n2026-09-16,Packaging,Stock,-148.90\n2026-09-18,Card takings,Sales,1697.30\n2026-09-20,Refund order 5480,Refunds,-36.00\n2026-09-21,Card takings,Sales,1402.10\n2026-09-22,HMRC VAT payment,Tax,-2318.44\n2026-09-23,Ceramic supplies,Stock,-655.00\n2026-09-25,Card takings,Sales,1888.65\n2026-09-27,Broadband,Utilities,-42.00\n2026-09-28,Card takings,Sales,1320.00\n2026-09-29,Wages,Payroll,-2400.00\n2026-09-30,Amazon payout,Sales,2245.18\n2026-10-02,Insurance,Insurance,-96.50\n2026-10-04,Card takings,Sales,1105.25\n\nBuild a weekly cash-flow summary using weeks commencing Monday. For each week: week_commencing (YYYY-MM-DD, the Monday), money_in, money_out (as a positive number), net, closing_balance. Then give the final closing_balance, the spending category with the largest total outflow over the whole period and that total, and the week_commencing with the lowest closing balance.\n\nJSON keys: weeks (list of objects with the keys above), closing_balance, largest_outflow_category, largest_outflow_total, lowest_closing_week.\nEnd your answer with exactly one JSON object in a ```json code block, with the keys shown. Numbers as plain numbers (no \u00a3 or commas)."
}