fish-agents

Baseline agents for Fish, a six-player team card game of asking, deduction and calls, and the interface they share, from the Fish benchmark.

• Agent: an agent is any object with act(view, rng) -> int. It sees only its own seat's view and draws its randomness from the generator it is given, so games replay exactly.
• B0 (b0-v1): plays uniformly at random among its legal actions, except that in a declaration window it passes all but 1 time in 100.
• play_game(agents, seed) plays one game with six agents and returns its record (needs the env extra).
• Memory: Remembering(agent, setting) gives an agent with act(view, memory, rng) full, last-k or no memory of the events it has been shown, and exactly what it can deduce from them.

from fish_agents.b0 import B0
from fish_agents.play import play_game

record = play_game([B0()] * 6, 42)
print("winner: team", record["winner"])

An agent with memory: it asks for a card whenever what it remembers proves the target holds it, and otherwise plays as B0. With full memory it beats three B0s more often than not:

from fish_agents.b0 import B0
from fish_agents.memory import FULL, Memory, Remembering
from fish_agents.play import play_game
from fish_rules.action_index import decode
from fish_rules.events import Ask
from fish_rules.rng import SplitMix64
from fish_rules.view import PlayerView


class Sure:
    """Asks for a card whenever Layer 1 says the target certainly holds it; otherwise B0."""

    def act(self, view: PlayerView, memory: Memory, rng: SplitMix64) -> int:
        for index in view.legal:
            action = decode(view.seat, index, view.phase)
            if isinstance(action, Ask) and memory.deduction.known(action.card) == action.target:
                return index
        return B0().act(view, rng)


games = [play_game([Remembering(Sure(), FULL)] * 3 + [B0()] * 3, seed) for seed in range(20)]
print("Sure won", sum(game["winner"] == 0 for game in games), "of 20 games against B0")

Install with pip install "fish-agents[env]" (Python 3.14 or later), or pip install fish-agents for the interface and agents alone. Stronger baselines (B1 to B3) come in later releases. Documentation is in the repository.

Licensed under Apache-2.0.