rules.md

Garble rules

Seats, commodities and contracts

• Five seats, always. In-game they are anonymous cog aliases drawn from the seed; a policy display name never reaches a seat.
• Four commodities in fixed index order: ORE (0), OAT (1), TIN (2), TAR (3). The names are chosen so a channel swap produces a valid but wrong commodity: ORE <-> OAT and TIN <-> TAR are the only confusable pairs.
• Prices are public, current and previous turn. The whole path is drawn at init from the seed: price[0][c] = 8 + rand(6), then a -1/0/+1 walk clamped to 3..30.
• Endowment. Seat s starts with 20 units of its surplus commodity, 0 of everything else, and 120 credits.
• Contract. Seat s is paid premium[s] (6..9) credits for each unit of its demand commodity dem[s] held at the horizon, up to quota[s] (12..19) units. Beyond the quota those units are worth only the market price. A seat's own contract is private - nobody else learns its demand commodity, its premium or its quota except by inference from what it says.

The wire

A transmission is one line of text. The exchange normalises it before anything else: uppercase, every character outside [A-Z0-9] replaced by a space, split on whitespace, truncated to 32 words.

Four word classes; everything else is chatter:

There are no compound spellings: TWENTY FIVE is two number words worth 20 and 5, not 25. Round numbers can be spoken; odd ones must be digits - which matters, because digits garble more widely than words.

The scanner, exactly

Run identically on the said text and on every heard text:

1. v = the smallest index with words[v] in {SELL, BUY}. None => no terms (the transmission is chatter).
2. a = the smallest index > v with words[a] == "AT". None => no terms.
3. side = SELL or BUY from words[v], stated from the transmitter's point of view.
4. qty = the modal value among the number words in words[v+1 .. a-1]; ties in multiplicity break toward the last such word. No number word there => no terms. kQty = the multiplicity of that modal value.
5. commodity = the modal commodity word in words[v+1 .. a-1]; ties break toward the last. None => no terms. kCom = its multiplicity.
6. price = the modal value among the number words in words[a+1 ..]; ties break toward the first. None => no terms. kPrice = its multiplicity.
7. qty and price are in 0..99 by construction. qty == 0 => no terms.

The modal rule is the whole robustness mechanic: SELL 5 5 5 ORE ORE AT 12 12 12 survives one garble per field by majority vote, and costs 26 characters of airtime against the 20 of SELL 5 ORE AT 12.

Interference and delivery

interference[t] is one public value per turn in [0.05, 0.95], a cosine swell of period max(6, turns div 2) with a random phase, plus 0.35 on a burst turn, all scaled by noiseScale and clamped. The base curve for every turn of the episode is published from turn 0 - a policy can plan to talk in the quiet. The bursts are not: they are the surprise.

Effective noise is n = interference[t] * chanFactor, with chanFactor = 1.0 on the radio and 0.6 on a private line. Per word, drawing r uniform in [0,1):

1. r < 0.45*n -> DROP: the word vanishes.
2. r < 0.85*n -> SWAP: the word is replaced by a uniform draw from its neighbour set; if that set is empty the word drops instead.
3. otherwise -> clean.

Then, on a burst turn, a static burst blanks a contiguous run of 2-4 words at the same positions for every delivery in that turn - the burst is weather, not per-listener luck.

Each recipient gets its own independent garbling, and the RNG depends only on (seed, turn, from, to) - so a replay re-derives every mishearing from the said text alone and nobody can fake a mishear they did not get.

The neighbour table - the only admissible mishearings

So 5 -> {50, 4, 6} (three ways to be misheard) but FIVE -> {NINE} (one): spelling a number out narrows its mishearing surface at the cost of four extra characters of airtime. Structure words never swap, so a structural garble voids a reading rather than inverting it: you can lose a deal to noise, you cannot be flipped from seller to buyer.

Tickets

The words are noisy; the exchange is not. When a seat's said text parses, the exchange opens a ticket with a sequential id, tagged with the offerer's alias, the channel, the turn it opened and the turn it expires. The ticket id, the offerer and the channel are delivered reliably. Only the terms are what you heard.

• A ticket opened on turn t may be confirmed on turns t+1 and t+2. It cannot be confirmed on turn t - decisions are simultaneous. It expires at the open of turn t+3.
• A radio ticket may be confirmed by any seat except the offerer. A line ticket only by the addressed seat.
• If two seats confirm the same ticket in one turn they resolve in seat index order; the first admissible confirm settles it and every later confirm that turn voids as already-settled.
• If the said text does not parse, no ticket exists - even if some listener's garbled version happens to parse. Listeners always know the real ticket ids, so this never bites an honest seat.

Confirming - binding as heard, with the redundancy shield

A confirm names a ticket and asserts side, qty, commodity, price. Those asserted fields are what the exchange enforces, not what the offerer said.

For each of qty, commodity, price: the asserted value is admissible if it equals the said value. Otherwise it is admissible only if the said field was transmitted once (k == 1) and the asserted value is the value of a member of the neighbour set of that single said word. If the offerer said the field twice or more with the same value (k >= 2), only the exact said value is admissible.

side is never a near-neighbour of anything, so an asserted side must equal the said side.

Worked examples.

• Offerer says SELL 5 ORE AT 12 (kQty = kCom = kPrice = 1). A confirm of SELL 50 ORE AT 1 is admissible: 50 is a neighbour of 5 and 1 is a neighbour of 12. The deal settles on the confirmed terms - the offerer sells up to 50 units at 1 credit.
• Offerer says SELL 5 5 ORE ORE AT 12 12 (k = 2, 2, 2). The same confirm voids, reason inadmissible. One repeat kills strategic mishearing on that field, and it costs airtime.
• Offerer says SELL FIVE ORE AT 12. A confirm of qty = 9 is admissible (FIVE <-> NINE); qty = 50 is not. Spelling narrows the surface.
• The shield also converts honest mishearings into voids rather than bad settlements: if the offerer repeated and the listener genuinely misheard the majority, the confirm voids and a turn is burned.

The turn, in order

1. Deadline check. Play stops between turns at 60% of the episode timeout; the episode settles with reason = "deadline", scored on the turns played.
2. Open. Expire stale tickets, publish price[t] and interference[t].
3. Observe. One observation per seat, from the state at open.
4. Decide. All non-scripted seats' LLM calls go out as ONE parallel batch.
5. Validate -> retry once -> scripted quoter fallback. An inadmissible confirm is a perfectly legal move whose outcome is a void; it is never retried and never falls back.
6. Transmit, in seat order. Text is rune-truncated to 160 runes, then to 32 words; airtime is charged at one rune per character; an over-budget text is cut on a rune boundary and flagged clipped; an empty meter makes the turn silent. If the said text parses, the ticket opens.
7. Confirms, in seat order, after every transmission of the turn has landed. A confirm costs a flat 40 runes and is never blocked by an empty meter - a seat can always settle. Resolution order: unknown/expired/already-settled/ own-ticket/not-addressed -> void; side mismatch -> void; any field inadmissible -> void; coverage (fill = min(qty, seller units, buyer cash div price)), fill == 0 -> void reason uncovered; otherwise settle and publish both versions on the public tape.
8. Pace, then continue or settle.

Airtime

900 runes for the whole episode, per seat. A transmission costs its length in runes; a confirm costs a flat 40. Run out and transmissions stop going out, though you can always still confirm. Repeat-backs, spelled numbers and redundant phrasing all cost airtime while the market moves.

Caps

Every truncation is on rune boundaries - a string cut mid-UTF-8 renders in a browser but fails a strict JSON parser, and every string here lands in the replay.

What each seat sees

Endings

results.reason has exactly two legal values:

There is no third value, no forfeit and no early win. A seat that never connects a player socket is not an ending: after the connect timeout the episode starts anyway and unprompted seats play with an empty operator block.