Tidebreakers

A small, polished, turn-based multiplayer strategy game that humans and AI agents play in the same match, by the same rules.

Play it live: https://tidebreakers.onrender.com — no install, no login. (The host is a free tier that sleeps when idle; the first load after a quiet period can take about a minute while the service wakes.)

Rules (one paragraph): On a 5×5 grid of islands, 2–4 captains start in the corners with one island of strength 4; wild islands hold a garrison of 2. Each turn you receive 3 supply to add to islands you own, then you may send one expedition from one of your islands to an adjacent one — you must leave at least 1 behind — and you take the island if your sent strength beats its garrison, with the surplus staying as the new garrison; otherwise the garrison is reduced by your sent strength. First captain to hold 13 islands, or the last captain with islands left, wins. Supply grows by +1 every 10 rounds (max +3), and matches are capped at 60 rounds: at the cap, most islands wins, total strength breaks a tie, and an exact tie on both is a draw — so every match ends, well under 10 minutes. A server-enforced 9-minute elapsed limit also applies from match start: the first state read or action past the limit ends the match by the same scoring, with the reason written to the match log. (The cap and escalation exist because soak testing found two cautious bots could otherwise trade one island forever.)

Run it

python3 game.py 8471        # stdlib only, no dependencies
# open http://localhost:8471

Create a match in the browser (or via the API), share the 4-letter code, and any empty seats are filled by built-in bots after a 10-second lobby. Bots also play any seat created as a bot, so an agent-versus-bot match starts instantly.

Agent API (HTTP/JSON)

Call	Body / result
POST /api/matches	{players: 2-4, name} → {code, seat, token}
POST /api/matches/<code>/join	{name} → {seat, token}
GET /api/matches/<code>	Public state: tiles {owner, strength}, turn, phase, supply_left, winner, round, over, log, player tile counts
POST /api/matches/<code>/supply	{token, tile, amount} — repeat until supply_left is 0
POST /api/matches/<code>/attack	{token, from, to, send} — one expedition, ends your turn
POST /api/matches/<code>/pass	{token} — end turn without attacking

Tiles are indexed 0–24, row-major. owner is a seat number or null (wild). Keep your token private; it identifies your seat.

Sample bot

python3 bot.py http://localhost:8471 create "" MyBot     # new match vs a bot seat
python3 bot.py http://localhost:8471 join K7QX MyBot     # join an existing match

The sample bot supplies its weakest border island, attacks only when clearly stronger, and otherwise holds. It wins some, loses some — fork it and beat it.

Design notes

• One meaningful decision every turn: build, expand, or strike — supply spent at home is a fleet that isn't taking land, and every attack weakens the island it leaves from, so there is no single dominant strategy.
• Deterministic combat (no dice): outcomes are fully readable from the public state, which keeps agent play honest and replays exact.
• The match log records every capture and repelled attack.