arena/configs/grand_exchange_live.toml

# grand-exchange-live — see environments/grand_exchange_live for what it measures.
#
#   uv run --project environments/grand_exchange_live eval @ configs/grand_exchange_live.toml \
#     --model <model-id>
#
# Eight looks per episode against one basket, so a rollout here costs roughly eight times a
# one-shot `grand-exchange` rollout in requests and rather more than that in tokens: the
# whole conversation is replayed to the model on every segment. `num_tasks` is half the
# one-shot config's for that reason, not because fewer baskets measure better — realised
# P&L over sixty ticks is the noisiest number in this repository and the ladder is read
# over five blocks of twenty-four.
num_tasks = 8
num_rollouts = 2

[env.taskset]
id = "grand-exchange-live"
num_items = 5   # items in the basket, one per price tier
visible = 56    # warmup ticks, read before the first look
# The graded window is not configurable: 8 looks x 7 ticks + a 4-tick tail = 60, and every
# constant in the reward was measured against that shape (`measure_ladder.py --sweep-shape`).

[env.agent.harness]
id = "null"    # pure-trace reward: a chat loop, no tools, no runtime

[env.agent.runtime]
# ⚠️ REQUIRED since verifiers 0.3.1, which changed the default agent runtime from
# `subprocess` to `prime` — a REMOTE sandbox. Without this the run exits
# `SystemExit: not authenticated with prime` before a single rollout, having already created
# its output directory and a zero-line traces.jsonl, so it reads as a failed eval rather than
# an unauthenticated one. Nothing here needs a sandbox: the reward is a pure function of the
# trace and the harness is `null`.
type = "subprocess"