diff --git a/SAC_LSTM_Bot/make_twin.sh b/SAC_LSTM_Bot/make_twin.sh
index 2858cee..1955b28 100755
--- a/SAC_LSTM_Bot/make_twin.sh
+++ b/SAC_LSTM_Bot/make_twin.sh
@@ -46,6 +46,11 @@ cat > "$TARGET/SacTwin.sh" <<'EOF'
 DIR="$(cd "$(dirname "$0")" && pwd)"
 export SACLSTM_BOT_JSON="$DIR/SacTwin.json"
 export SACLSTM_WEIGHTS_PATH="$DIR/weights/sac_latest.zip"
+# Freeze contract (#54): the twin is a FROZEN sparring partner, not a
+# co-learner. Eval-mode gate (lever 4) suppresses all sendTrainingMsg traffic,
+# so the twin never trains — not even in-RAM within a battle. Without this,
+# any main-bot checkpoint-interval change would let twin drift accumulate.
+export SACLSTM_EVAL_MODE=1
 exec "$DIR/SAC_LSTM_Bot"
 EOF
 chmod +x "$TARGET/SacTwin.sh" "$TARGET/SAC_LSTM_Bot"