Cycle 1: c_puct 3->5, dirichlet_eps 0.25->0.4 produced first natural-end wins

50-iter sweep on default.yaml with stronger MCTS exploration:
- c_puct: 3.0 -> 5.0 (UCB weight, more exploration of low-prior actions)
- root_dirichlet_epsilon: 0.25 -> 0.4 (more noise injected at root prior)

Standalone eval at iter 50 (30 games/opponent, all natural-end, timeouts=0):
- vs heuristic-balanced:    W=0/30 S=-70.5  (PA 0.15)
- vs heuristic-aggressive:  W=2/30 S=-65.1  (PA 0.14)  [+10, +4]
- vs heuristic-cautious:    W=1/30 S=-48.0  (PA 0.14)  [+2]

3 natural-end wins vs prev trapfix baseline iter 44 (which had 0 natural
wins + 1 timeout-tie). Stall trap fixed remains true (timeouts=0 in c1).

Trade-off observed: more exploration -> higher variance. Score avg vs
cautious worsened (-32 -> -48), but win events appeared. For the
non-terminal-win objective, exploration win > score-avg loss.

Next: commit to long run (300 iter) with these params before tuning more.

scripts/autonomous_cycle_eval.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+# Autonomous cycle eval helper.
+# Usage: ./autonomous_cycle_eval.sh <run-prefix> [extra eval args...]
+# Finds latest run matching prefix, runs eval --ckpt latest.pt with 30 games,
+# and reports: timeouts, natural-end wins per opponent.
+
+set -euo pipefail
+
+PREFIX="${1:-}"
+shift || true
+
+if [ -z "$PREFIX" ]; then
+    echo "usage: $0 <run-prefix> [extra eval args...]"
+    exit 1
+fi
+
+RUN=$(ls -td runs/*${PREFIX}* 2>/dev/null | head -1)
+if [ -z "$RUN" ]; then
+    echo "no run matching ${PREFIX}" >&2
+    exit 1
+fi
+
+CKPT="$RUN/latest.pt"
+if [ ! -f "$CKPT" ]; then
+    echo "no checkpoint at $CKPT" >&2
+    exit 1
+fi
+
+echo "=== eval $CKPT ==="
+uv run lost-cities-ismcts eval --ckpt "$CKPT" --games 30 --verbose "$@" 2>&1