diff --git a/Makefile b/Makefile
index 022a5ed8..de74fd18 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: verify-phase6 verify-enet-integration verify-steam-templates verify-supply-chain verify-kind-agones verify-allocated-compose verify-multiplayer-local verify-multiplayer-load
+.PHONY: verify-phase6 verify-enet-integration verify-steam-templates verify-supply-chain verify-kind-agones verify-allocated-compose verify-multiplayer-local verify-multiplayer-load verify-release-gate
 
 verify-multiplayer-local:
 	bash scripts/verify_multiplayer_local.sh
@@ -6,6 +6,10 @@ verify-multiplayer-local:
 verify-multiplayer-load:
 	(cd server && go test -tags load ./api -run TestQueueCreateHTTPLoad -count=1)
 
+verify-release-gate:
+	@test -n "$(RELEASE_REPORT)" || (echo "RELEASE_REPORT=/path/to/report.json is required" >&2; exit 2)
+	python3 scripts/verify_release_gate.py "$(RELEASE_REPORT)"
+
 verify-phase6:
 	bash scripts/verify_phase6.sh
 
diff --git a/multiplayer-next.md b/multiplayer-next.md
index f20379e3..ce303146 100644
--- a/multiplayer-next.md
+++ b/multiplayer-next.md
@@ -1252,7 +1252,7 @@ the local/CI/community transport, not a silent production fallback.
 | 8.50 `[D:8.25,8.37,8.43,8.49]` | Network/chaos suite: 100 ms RTT, jitter/loss, client/API/matcher restart, game-pod death, node drain, Redis failover and control-plane loss | System recovers to a defined state; infrastructure-caused cases cannot penalise affected players |
 | 8.51 `[D:8.17,8.18,8.30,8.31,8.45]` | **IN PROGRESS.** The opt-in `make verify-multiplayer-load` gate drives 10,000 real HTTP queue-create requests through the service with 256 in flight and records p95/p99; the handler and in-process ownership boundary are exercised without weakening normal tests | Local API load passes at p95 <250 ms in normal and race runs; PostgreSQL saturation, >=100 proposals/s, durable matcher fencing under load, forecast launch concurrency x2, and replica scaling remain live infrastructure gates |
 | 8.52 `[D:8.32,8.34,8.45,8.51]` | **IN PROGRESS.** Allocator now supports an opt-in, per-replica fixed-window allocation quota per EU/NA region (`--allocation-quota` / `--allocation-quota-window`), checked before any provider call and safe under concurrent attempts | Normal/race/vet tests cover quota exhaustion, window reset, region isolation, invalid input, and atomic concurrent consumption; measured regional cost model, shared/global quota, budget alerts, and denial-of-wallet production rehearsal remain |
-| 8.53 `[D:7.8,8.13,8.38,8.45,8.46,8.48,8.49,8.50,8.51,8.52]` | Progressive release: development → internal → casual canary → casual → provisional ranked → ranked | Each promotion requires SLO/security/cost gates, rollback rehearsal, EU+NA playtests and unchanged legacy gates; rollback criteria and owner are explicit |
+| 8.53 `[D:7.8,8.13,8.38,8.45,8.46,8.48,8.49,8.50,8.51,8.52]` | **IN PROGRESS.** `scripts/verify_release_gate.py` provides a fail-closed promotion check for the ordered development → internal → casual canary → casual → provisional ranked → ranked stages, requiring an evidence report for SLO, security, cost, rollback, EU+NA playtests, and both legacy gates | Validator and adversarial tests cover skipped stages, unknown stages, missing gates, non-boolean gate values, and blank release IDs; the actual reports, production rollback rehearsal, regional playtests, and live promotion remain open |
 
 Implementation invariants for every task above:
 
diff --git a/scripts/test_verify_release_gate.py b/scripts/test_verify_release_gate.py
new file mode 100644
index 00000000..47f408c2
--- /dev/null
+++ b/scripts/test_verify_release_gate.py
@@ -0,0 +1,56 @@
+import sys
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent))
+
+from verify_release_gate import validate_release_report
+
+
+def valid_report():
+    return {
+        "release_id": "release-2026-09-01-001",
+        "from_stage": "development",
+        "to_stage": "internal",
+        "slo_passed": True,
+        "security_passed": True,
+        "cost_passed": True,
+        "rollback_rehearsed": True,
+        "playtests": {"eu_passed": True, "na_passed": True},
+        "legacy": {"phase6_passed": True, "enet_passed": True},
+    }
+
+
+class ReleaseGateTest(unittest.TestCase):
+    def test_accepts_one_complete_promotion(self):
+        self.assertEqual(validate_release_report(valid_report()), ("development", "internal"))
+
+    def test_rejects_skipped_stage(self):
+        report = valid_report()
+        report["to_stage"] = "casual"
+        with self.assertRaises(ValueError):
+            validate_release_report(report)
+
+    def test_rejects_missing_or_false_gate(self):
+        report = valid_report()
+        del report["playtests"]["na_passed"]
+        with self.assertRaises(ValueError):
+            validate_release_report(report)
+        report = valid_report()
+        report["cost_passed"] = 1
+        with self.assertRaises(ValueError):
+            validate_release_report(report)
+
+    def test_rejects_unknown_stage_and_blank_release(self):
+        report = valid_report()
+        report["release_id"] = "  "
+        with self.assertRaises(ValueError):
+            validate_release_report(report)
+        report = valid_report()
+        report["from_stage"] = "experimental"
+        with self.assertRaises(ValueError):
+            validate_release_report(report)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/scripts/verify_release_gate.py b/scripts/verify_release_gate.py
new file mode 100644
index 00000000..1faf251d
--- /dev/null
+++ b/scripts/verify_release_gate.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+"""Fail-closed validation for a multiplayer promotion evidence report."""
+
+import json
+import sys
+from typing import Any
+
+
+STAGES = ("development", "internal", "casual-canary", "casual", "provisional-ranked", "ranked")
+
+
+def _required_true(report: dict[str, Any], key: str) -> None:
+    value: Any = report
+    for part in key.split("."):
+        if not isinstance(value, dict) or part not in value:
+            raise ValueError(f"missing gate: {key}")
+        value = value[part]
+    if value is not True:
+        raise ValueError(f"gate did not pass: {key}")
+
+
+def validate_release_report(report: dict[str, Any]) -> tuple[str, str]:
+    if not isinstance(report, dict):
+        raise ValueError("release report must be an object")
+    source = report.get("from_stage")
+    target = report.get("to_stage")
+    if source not in STAGES or target not in STAGES:
+        raise ValueError("from_stage and to_stage must be known release stages")
+    if STAGES.index(target) != STAGES.index(source) + 1:
+        raise ValueError(f"promotion must advance exactly one stage: {source!r} -> {target!r}")
+    if not isinstance(report.get("release_id"), str) or not report["release_id"].strip():
+        raise ValueError("release_id is required")
+    for gate in (
+        "slo_passed", "security_passed", "cost_passed", "rollback_rehearsed",
+        "playtests.eu_passed", "playtests.na_passed", "legacy.phase6_passed",
+        "legacy.enet_passed",
+    ):
+        _required_true(report, gate)
+    return source, target
+
+
+def main() -> int:
+    if len(sys.argv) != 2:
+        print(f"usage: {sys.argv[0]} report.json", file=sys.stderr)
+        return 2
+    try:
+        with open(sys.argv[1], encoding="utf-8") as handle:
+            source, target = validate_release_report(json.load(handle))
+    except (OSError, ValueError, json.JSONDecodeError) as error:
+        print(f"release gate failed: {error}", file=sys.stderr)
+        return 1
+    print(f"release gate passed: {source} -> {target}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())