Treasury and budget

Owns one money stock and a ledger of flow categories. Each accounting period income (taxes, fees, sales, trade) is added and expenses (upkeep, wages, service funding, interest) are subtracted. Players often set a funding fraction per department, and service effectiveness scales with it. In Micropolis, the open-source SimCity engine, the collection every 48 city-time steps computes revenue = population x average land value / 120 x tax rate x a difficulty factor, sets required police and fire funds at 100 per station and road funds per road and rail tile, and converts the fraction actually paid into RoadEffect (0-32) and PoliceEffect and FireEffect (0-1000), so underfunded roads decay and coverage shrinks. A negative balance leads to loans, bonds, bankruptcy, or game over; SimCity 2000 ends the game after extreme deficit spending.

Periodic reckoning. The player watches a running balance and a monthly or yearly ledger, trims service budgets to stay solvent, and decides when a surplus should become new construction. Shortfalls show up as visible decay: crumbling roads, slower fire response, unpaid staff.

• accounting period length and whether flows post continuously or at fixed ticks
• which expense categories are player-adjustable and how effectiveness scales with the funding fraction
• upkeep per building relative to the revenue it enables
• consequence of a negative balance (borrowing, forced cuts, bankruptcy, or game over)
• how much ledger detail and forecasting the interface shows

• Upkeep that scales slower than revenue makes money irrelevant by mid-game, a common complaint about Cities: Skylines.
• Funding sliders whose effects are delayed or hidden teach players to cut services without visible cost until a collapse.
• Fixed upkeep with no link to growth produces an early cash trap with no recovery path.

• Surpluses fund expansion that raises both revenue and upkeep, so cash pressure returns at each growth stage.
• Underfunding one service degrades a dependent system (roads, crime, fires), which later lowers the revenue base.
• Periodic settlement creates sawtooth cash curves and end-of-period scrambles.

• Can an LLM advisor explain a deficit as a causal chain through the ledger well enough to replace spreadsheet-style budget panels?
• What upkeep-to-revenue curve keeps money a meaningful constraint into the late game?