Markette

A small town where the shopkeepers are software

Each shopkeeper holds its own wallet. It works out what it has run short of, walks across town to whoever is selling it, and pays — under spending limits it cannot talk its way past. Everything it considered, and every rule that checked it, is on screen while it happens.

Watch the town How it works

8shopkeepers

8goods

every purchase checked against7rules

The loop

What a shopkeeper does on its turn

The same five steps run for each shopkeeper, over and over, and all five are on screen while they happen.

The shopkeeper looks around.

It reads its own shelves, its own coin, and what every other shop has out this second. That short list of observations is the whole of what it knows.

It works out every option and scores them.

Buy flour, bake bread, put stock out front, drop a price, wait — each one gets a score and a plain reason. The options it turned down stay on screen beside the one it took.

If two options are close, it asks a model to choose — but only from that list.

When the top two are within a hair of each other, the shopkeeper asks a model which to take. The model answers with a number from the list; it cannot add an option of its own.

Seven spending rules check the purchase before any money moves.

The per-purchase limit, the budget for the stretch, the approved-payee list and four more all have to pass. You see every verdict, including the ones that said yes.

It walks to the shop, pays, and the goods change hands.

The shopkeeper crosses town to the seller's door before anything settles, so the money and the movement stay joined up. Then the coins go one way, the goods the other, and both wallets show it.

The cast

Who lives here

Nobody reports to anybody. Each shopkeeper holds its own coin, keeps its own shelves, and buys from whichever neighbour is selling what it has run short of.

Wren

Farmer

Wren farms the west field. She is unhurried, sells wheat to anyone, and only ever buys tools and supper.

Makes 6 wheat straight out of the ground, with nothing to buy in first.

West Field

Odette

Miller

Odette runs the mill. She is exacting about margins and will not buy wheat above what her flour can carry.

Makes 2 flour from 2 wheat.

The Mill

Bram

Baker

Bram bakes before dawn and panics when the flour bin runs low. He would rather overpay than close the shop.

Makes 4 bread from 2 flour.

The Bakery

Tess

Brewer

Tess brews ale in the south yard. She buys wheat in bulk when it is cheap and sits on stock otherwise.

Makes 3 ale from 3 wheat.

The Brewery

Pike

Miner

Pike works the east seam. He goes through tools fast and grumbles about the smith's prices every time.

Makes 4 ore straight out of the ground, with nothing to buy in first.

The Mine

Halvard

Smith

Halvard forges tools and lanterns. He knows the farmer and the miner cannot work without him and prices accordingly.

Makes 2 tools and 1 lantern from 3 ore.

The Forge

Marlow

Innkeeper

Marlow runs the inn at the crossroads. He needs bread and ale constantly and will pay a premium to never run dry.

Makes 3 meal from 1 bread and 1 ale.

The Inn

Sable

Trader

Sable makes nothing. She buys whatever the town has too much of and sells it back when it runs short.

Makes nothing — trades in wheat, flour, bread, ore, tools, lantern, ale and meal, buying them cheap and selling them back when the town runs short.

Sable's Cart

What keeps it honest

The model picks a number, never a payee

When a shopkeeper is torn between two options, it asks a model to choose. The model is not handed a wallet. It is handed a numbered list the town has already worked out and already checked, and it answers with one of those numbers.

So it never names who gets paid and it never sets an amount. Text a shopkeeper reads — a sign in a window, a neighbour's sales patter — cannot talk it into a payment the rules would have stopped. The worst a bad answer can do is take an option that was already allowed.

If the model cannot be reached, the shopkeeper falls back on the town's own scoring and carries on with its day.

The 7 rules

Every one of them runs before a single coin moves, and the town view shows each verdict — including the ones that said yes.

Town circuit breaker — If the town is paused or halted, nothing gets paid, no matter who asks.

The shopkeeper's own status — A suspended shopkeeper can still walk about, but it cannot pay anyone until it is let back in.

Spending switch — Spending can be switched off for one shopkeeper by hand, and stays off until you switch it back.

Per-purchase limit — A ceiling on any single purchase — 2.50 USDC to start with. Above it, the purchase never happens.

Budget for the stretch — Everything spent in one budget period, capped at 8.00 USDC. Money already promised to an errand counts against it.

Approved-payee list — A shopkeeper can only pay addresses on its own list. Everybody else is simply unreachable.

Money on hand — Coins set aside for an errand already underway do not count. It can only spend what is genuinely free.

FAQ

What people ask before they press play

Is the money real?

No. Payments settle on a simulated ledger unless a testnet chain is configured, and the town view always names which of the two you are watching. Everything else — the shopkeepers, the shops, the shortages — is really running.

Do I need an API key?

No. The town runs, trades and settles on its own scoring without one. Add an OPENAI_API_KEY and the shopkeepers also think the close calls through, and you get to read what they thought.

Which model does the thinking?

Whatever MARKETTE_MODEL is set to, and gpt-5-mini if you leave it alone. The model, the tokens it used and a running cost estimate sit next to every decision it touched.

Can I break it?

Yes, and that is rather the point. Drop a shopkeeper's per-purchase limit below the price of flour, watch the next purchase get stopped, and see which rule stopped it named on screen.

Is it the same every time?

Yes — same seed, same town. The same shopkeepers start in the same spots with the same coins and the same shelves. Asking a model is the only thing that varies, and only on close calls.

Where does it keep all this?

In memory on the server. Nothing is written to a database, so restarting begins a fresh day with a clean set of wallets.

The model picks a number, never a payee

If the model cannot be reached, the shopkeeper falls back on the town's own scoring and carries on with its day.