diff --git a/runs/frontier-fidelity-envelope-v1/run_qwen30_latency_case_real_surface.sh b/runs/frontier-fidelity-envelope-v1/run_qwen30_latency_case_real_surface.sh
index 553a93d..f8136b3 100644
--- a/runs/frontier-fidelity-envelope-v1/run_qwen30_latency_case_real_surface.sh
+++ b/runs/frontier-fidelity-envelope-v1/run_qwen30_latency_case_real_surface.sh
@@ -32,6 +32,7 @@ esac
 for path in "${RUNNER}" "${CLIENT}" "${PREFILL_CLIENT}" "${MODEL_ROOT}/config.json"; do
   [[ -f "${path}" ]] || { echo "ERROR: required path is missing: ${path}" >&2; exit 1; }
 done
+mkdir -p "${OUT}"
 
 declare -a WAVE_PIDS=()