diff --git a/bench/drc_check.sh b/bench/drc_check.sh
new file mode 100755
index 0000000..db2e9ec
--- /dev/null
+++ b/bench/drc_check.sh
@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+# Route one KiCad board with freeroute and judge the result with KiCad's DRC.
+#
+#   bench/drc_check.sh [--keep] <board.kicad_pcb> <out-dir> [freeroute args...]
+#
+# Copies the board (and its .kicad_pro) into <out-dir>, strips its tracks and
+# vias unless --keep is given (then they reach the router as fixed wiring),
+# exports the DSN through mckicad, routes, applies the session, and runs DRC
+# with zones refilled at every severity. Prints one line: time, copper added,
+# shorts, opens, hole problems (whatever severity the board gives them) and
+# the other errors. The source board is never touched.
+#
+# FREEROUTE (default: this checkout's .venv/bin/freeroute) and MCK (default
+# ~/claude/mckicad) pick the builds to judge.
+set -euo pipefail
+keep=0
+if [[ "${1:-}" == "--keep" ]]; then keep=1; shift; fi
+src="$1"; out="$2"; shift 2
+here="$(cd "$(dirname "$0")/.." && pwd)"
+FREEROUTE="${FREEROUTE:-$here/.venv/bin/freeroute}"
+MCK="${MCK:-$HOME/claude/mckicad}"
+rm -rf "$out"; mkdir -p "$out"
+cp "${src%.kicad_pcb}.kicad_pro" "$out/board.kicad_pro" 2>/dev/null || true
+
+if [[ $keep == 1 ]]; then
+    cp "$src" "$out/board.kicad_pcb"
+else
+    (cd "$MCK" && uv run --no-sync python - "$src" "$out/board.kicad_pcb" <<'EOF'
+import sys
+from mckicad.utils.sexp_tree import parse
+text = open(sys.argv[1]).read()
+spans = sorted((c.span for c in parse(text).children if c.tag in ("segment", "arc", "via")), reverse=True)
+for a, b in spans:
+    text = text[:a] + text[b:]
+open(sys.argv[2], "w").write(text)
+EOF
+    )
+fi
+
+(cd "$MCK" && uv run --no-sync python -c "
+from mckicad.utils.freerouting import FreeRoutingEngine
+assert FreeRoutingEngine().export_dsn_from_kicad('$out/board.kicad_pcb', '$out/board.dsn', {})") \
+    >/dev/null 2>&1 || { echo "$out: DSN export failed"; exit 1; }
+
+start=$(date +%s.%N)
+"$FREEROUTE" "$out/board.dsn" -do "$out/board.ses" "$@" >"$out/route.log" 2>&1 || true
+secs=$(python3 -c "print(round($(date +%s.%N)-$start,1))")
+[[ -s "$out/board.ses" ]] || { echo "$out: no session ($(tail -1 "$out/route.log"))"; exit 1; }
+
+(cd "$MCK" && uv run --no-sync python -c "
+from mckicad.utils.ses_apply import apply_ses_to_board as a
+r = a('$out/board.kicad_pcb', '$out/board.ses', '$out/board.kicad_pcb')
+print(r['segments_added'], r['vias_added'])" 2>/dev/null) >"$out/apply.txt"
+
+kicad-cli pcb drc --refill-zones --format json --severity-all \
+    -o "$out/drc.json" "$out/board.kicad_pcb" >/dev/null 2>&1 || true
+python3 - "$out" "$secs" <<'EOF'
+import collections, json, sys
+out, secs = sys.argv[1:]
+seg, via = open(f"{out}/apply.txt").read().split()
+d = json.load(open(f"{out}/drc.json"))
+errors = collections.Counter(v["type"] for v in d["violations"] if v.get("severity") == "error")
+other = collections.Counter(v["type"] for v in d["violations"] if v.get("severity") != "error")
+holes = {k: errors.pop(k, 0) + other.get(k, 0) for k in ("holes_co_located", "hole_to_hole")}
+print(f"{out}: {secs}s  {seg} seg {via} via  shorts {errors.pop('shorting_items', 0)}  "
+      f"opens {len(d.get('unconnected_items', []))}  holes {holes}  errors {dict(errors)}")
+EOF