diff --git a/tools/checklist-report.py b/tools/checklist-report.py
index b03af413..79471dc2 100755
--- a/tools/checklist-report.py
+++ b/tools/checklist-report.py
@@ -357,7 +357,10 @@ def ultimate_stress_verdict(results: list[tuple[int, dict]]) -> dict[str, Any]:
     turn_limit_seen = 0
     for _, r in results:
         outcome = r.get("outcome", "")
-        turn = int(r.get("turn", 0))
+        # `_collect` stores the final turn under "turns" (plural) at line ~89;
+        # reading "turn" (singular) here always returned 0 and made every
+        # ultimate_stress verdict fail with "median game length 0.0".
+        turn = int(r.get("turns", 0))
         turn_limit_seen = max(turn_limit_seen, turn)
         turns.append(turn)
         if outcome == "victory":