diff --git a/tools/sole-city-gate.py b/tools/sole-city-gate.py
new file mode 100644
index 00000000..2503b701
--- /dev/null
+++ b/tools/sole-city-gate.py
@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+"""sole-city-gate.py — score the p1-29c / p1-29d sole-city tier gate for a batch.
+
+Reads every game_*/turn_stats.jsonl under a batch dir, extracts per-player
+final tier_peak / cities / cities_lost, and scores the alive-aware gate:
+
+    PASS seed  := P0.tier_peak >= TIER AND P1.tier_peak >= TIER
+    Gate PASS  := pass_seeds >= QUORUM   (default 7/10)  AND
+                  median game length <= MAX_TURNS (default 384)
+
+Usage:
+    python3 tools/sole-city-gate.py <batch-dir> [--tier 2] [--quorum 7]
+                                      [--max-turns 384] [--p0 0] [--p1 1]
+
+Exit code 0 = gate PASS, 1 = gate FAIL, 2 = usage / no data.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import statistics
+import sys
+from pathlib import Path
+
+
+def final_line(ts: Path) -> dict | None:
+    last = None
+    for line in ts.read_text().splitlines():
+        line = line.strip()
+        if line:
+            last = line
+    if last is None:
+        return None
+    return json.loads(last)
+
+
+def main(argv: list[str]) -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("batch_dir")
+    ap.add_argument("--tier", type=int, default=2)
+    ap.add_argument("--quorum", type=int, default=7)
+    ap.add_argument("--max-turns", type=int, default=384)
+    ap.add_argument("--p0", default="0")
+    ap.add_argument("--p1", default="1")
+    args = ap.parse_args(argv[1:])
+
+    root = Path(args.batch_dir)
+    if not root.is_dir():
+        print(f"Not a directory: {root}", file=sys.stderr)
+        return 2
+
+    games = sorted(g for g in root.glob("game_*") if g.is_dir())
+    if not games:
+        print(f"No game_* dirs under {root}", file=sys.stderr)
+        return 2
+
+    rows = []
+    turns = []
+    pass_seeds = 0
+    for game in games:
+        ts = game / "turn_stats.jsonl"
+        if not ts.exists():
+            rows.append((game.name, "NO_STATS"))
+            continue
+        try:
+            final = final_line(ts)
+        except Exception as e:  # noqa: BLE001
+            rows.append((game.name, f"PARSE_ERR {e}"))
+            continue
+        if not final:
+            rows.append((game.name, "EMPTY"))
+            continue
+        ps = final.get("player_stats") or {}
+        p0 = ps.get(args.p0, {})
+        p1 = ps.get(args.p1, {})
+        turn = final.get("turn", 0)
+        turns.append(turn)
+        p0_tp = p0.get("tier_peak", 0)
+        p1_tp = p1.get("tier_peak", 0)
+        ok = p0_tp >= args.tier and p1_tp >= args.tier
+        pass_seeds += 1 if ok else 0
+        rows.append((
+            game.name,
+            f"T{turn} outcome={final.get('outcome')} "
+            f"P0_tp={p0_tp} P1_tp={p1_tp} "
+            f"P1_cities={p1.get('cities', '?')} P1_lost={p1.get('cities_lost', '?')} "
+            f"{'PASS' if ok else 'fail'}"
+        ))
+
+    for name, detail in rows:
+        print(f"{name}: {detail}")
+
+    scored = len(turns)
+    median_turn = statistics.median(turns) if turns else 0
+    quorum_ok = pass_seeds >= args.quorum
+    length_ok = median_turn <= args.max_turns
+    gate = quorum_ok and length_ok
+
+    print("─" * 60)
+    print(f"scored games:        {scored}")
+    print(f"pass seeds (P0_tp>={args.tier} AND P1_tp>={args.tier}): "
+          f"{pass_seeds}/{scored}  (quorum {args.quorum} → {'OK' if quorum_ok else 'MISS'})")
+    print(f"median game length:  {median_turn}  (<= {args.max_turns} → {'OK' if length_ok else 'MISS'})")
+    print(f"GATE: {'PASS' if gate else 'FAIL'}")
+    return 0 if gate else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))