Game Economy: Sources, Sinks and What Piles Up
Add up what comes into your game's economy, what goes out and what piles up, hour by hour of play. If coins pile up with nothing left to buy, the fix is usually more things worth buying, not smaller rewards.
What are sources and sinks?
A source creates money in the game, such as a quest reward. A sink removes it for good, such as a repair bill. Writer Brendan Drain explains it for online games: a faucet creates currency from nothing, a sink destroys it, and money that only passes between players is neither. When more comes in than goes out, a fixed amount of money buys less. In a single-player game, the same imbalance has a quieter effect: prices stop mattering, and so does earning.
How do you read an economy from data?
Quince Hollow Farm is an invented farming game, and these numbers are made up for this example. The maker looked at 60 sessions of about three hours, and took the usual player per hour.
| Hour of play | Coins in | Coins out | Share spent | Balance at the end |
|---|---|---|---|---|
| 1 | 900 | 820 | 91% | 80 |
| 2 | 1,250 | 540 | 43% | 790 |
| 3 | 1,570 | 470 | 30% | 1,890 |
Overall, 3,720 coins came in and 1,830 went out. That is 49% spent, or 1,240 coins in and 610 out per hour. The total alone would tell you there is a problem. The rows tell you when it starts.
Hour 1 is lovely: 91% spent, every coin a decision. Then income keeps rising while spending falls. By hour 3, a player spends less than a third of what they earn. The maker listed where the coins go.
| Sink | Share of spending | Used in sessions |
|---|---|---|
| Seeds | 54% | 60 of 60 |
| Tools | 38% | 52 of 60 |
| Decorations | 8% | 21 of 60 |
| Barn upgrade | 0% | 0 of 60 |
Players buy their tools in hour 1, and they never need them again. The barn upgrade costs 5,000 coins, so nobody gets near it. Between a 100-coin shovel and a 5,000-coin barn there is nothing to want.
Comparing the log with the plan turned up two more things. Among the sources was chest-reopen, with 4% of all income, which was not in the maker's list. Reloading a save let you open the same chest twice. That is a bug. And in 3 sessions the balance went below zero, which the plan says cannot happen: the seed shop never checked the wallet.
How do you fix a pile of coins?
Fix the two bugs first, as they distort everything else. Then add a sink.
- Add things worth wanting. The maker split the barn into three stages at 800, 1,500 and 2,700 coins, so each hour has a goal.
- Do not cut rewards first. Shrinking a reward feels like a punishment. A new goal feels like a gift.
- Do the sum. To spend 85% in hour 3, players must spend about 1,335 coins, so about 865 more than now.
A session report cannot show how money grows over many sittings, so also log the balance at the start of each one. Our economy check adds all this up, and catches money that appears from nowhere. For items nobody uses, read weapon and item usage.
Paste this to your AI
Check the economy of my game. The event log is in [file or folder].
1. Find every place in the code that gives or takes [coins]. List them as sources and sinks, with where each lives in the code, and draw the flow as a Mermaid state diagram.
2. Write down how much a player should have at each stage, and what they should want to buy next. Ask me if you do not know.
3. Check that the game logs every gain and spend, with its amount, what it was for and the balance after it. If not, add that first.
4. Use get_recipe with economy-balance-check if Spielerando is connected. Show totals, share spent, per-hour windows, and sources and sinks by size.
5. Compare with step 1 and 2: any source or sink not in the list, any listed sink nobody used, any balance below zero, any balance that differs from the running sum.
Treat those last ones as bugs, and show me the session counts. Then suggest one new sink for the hour where spending collapses, with the sum behind its price. If there are under 30 sessions, give me no verdict, only what you can see.
Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP
How to check it worked
- Reload a save and try to earn the same reward twice.
- Spend everything. Try to go below zero.
- Ask what you would buy next. At every stage, there should be an answer.
- Look at the rows, not the total. Each hour should now have a share you meant.