diff --git a/src/nsc/eval/gate.py b/src/nsc/eval/gate.py
index 8b38cbc..0509afc 100644
--- a/src/nsc/eval/gate.py
+++ b/src/nsc/eval/gate.py
@@ -1,12 +1,13 @@
-"""评测门禁（T-08b）：阈值加载 + JUDGE_GATE_ENABLED + 校准结果判定。
+"""评测门禁（T-08b）：阈值加载 + 校准结果判定。
 
 D8：未过校准门槛的判官只能出报告，不能参与门禁。
-`judge calibrate` 未过闸时会把仓库变量 JUDGE_GATE_ENABLED 写为 false（协议 §4）。
+`judge calibrate` 未过闸时会把 judge-calibration.yml 的 judge_gate_enabled 写为 false
+（协议 §4）。SW-04：门禁真相只在状态文件，环境变量不再有覆盖能力——
+环境开关等于给"未校准判官可门禁"留后门，与 D8 相悖。
 """
 
 from __future__ import annotations
 
-import os
 from pathlib import Path
 from typing import Any
 
@@ -20,15 +21,8 @@ def load_thresholds(path: str | Path = THRESHOLDS_PATH) -> dict[str, Any]:
     return yaml.safe_load(Path(path).read_text("utf-8")) or {}
 
 
-def gate_var_name() -> str:
-    return str(load_thresholds().get("l1", {}).get("judge_gate_enabled_var", "JUDGE_GATE_ENABLED"))
-
-
 def gate_enabled() -> bool:
-    """判官是否允许参与门禁。优先级：环境变量 > judge-calibration.yml > 默认开启。"""
-    val = os.environ.get(gate_var_name())
-    if val is not None:
-        return val.strip().lower() not in ("0", "false", "off", "no", "")
+    """判官是否允许参与门禁。真相：judge-calibration.yml > 默认开启（SW-04：无 env 覆盖）。"""
     if GATE_STATE_PATH.exists():
         data = yaml.safe_load(GATE_STATE_PATH.read_text("utf-8")) or {}
         return bool(data.get("judge_gate_enabled", True))
@@ -108,10 +102,10 @@ def main(argv: list[str] | None = None) -> int:
         ev = evaluate_calibration(metrics)
     else:
         if not GATE_STATE_PATH.exists():
-            # CI 场景（judge-calibration.yml 尚未提交）：回退到 gate_enabled() 的
-            # 环境变量（JUDGE_GATE_ENABLED）/ 默认开启，避免硬失败。
+            # CI 场景（judge-calibration.yml 尚未提交）：回退到默认开启，避免硬失败。
+            # SW-04：环境变量不再有覆盖能力（D8：未校准判官只能出报告）。
             enabled = gate_enabled()
-            print(f"无校准状态文件；JUDGE_GATE_ENABLED={str(enabled).lower()}")
+            print(f"无校准状态文件；gate_enabled={str(enabled).lower()}")
             return 0 if enabled else 1
         state = yaml.safe_load(GATE_STATE_PATH.read_text("utf-8")) or {}
         ev = evaluate_calibration(state.get("metrics") or {})
diff --git a/tests/test_judge.py b/tests/test_judge.py
index 5a58a61..df7bee3 100644
--- a/tests/test_judge.py
+++ b/tests/test_judge.py
@@ -227,16 +227,30 @@ def test_compute_metrics():
 
 
 # ---------------------------------------------------------------- 门禁
-def test_gate_enabled_respects_env(monkeypatch):
+def test_gate_enabled_ignores_env(tmp_path, monkeypatch):
+    """SW-04：环境变量不得覆盖校准门禁。D8 真相只在 judge-calibration.yml。
+
+    取代旧 test_gate_enabled_respects_env（其断言的 env 覆盖语义正是本卡移除对象，
+    冲突记录见 PR 描述）。
+    """
     from nsc.eval import gate as g
 
-    monkeypatch.setenv("JUDGE_GATE_ENABLED", "0")
-    assert g.gate_enabled() is False
+    state = tmp_path / "state.yml"
+    monkeypatch.setattr(g, "GATE_STATE_PATH", state)
     monkeypatch.setenv("JUDGE_GATE_ENABLED", "true")
-    assert g.gate_enabled() is True
-    monkeypatch.delenv("JUDGE_GATE_ENABLED")
-    monkeypatch.setattr(g, "GATE_STATE_PATH", Path("/nonexistent/state.yml"))
-    assert g.gate_enabled() is True  # 默认开
+    state.write_text("judge_gate_enabled: false\n", "utf-8")
+    assert g.gate_enabled() is False, "env=true 不得越过校准关闸"
+    monkeypatch.setenv("JUDGE_GATE_ENABLED", "0")
+    state.write_text("judge_gate_enabled: true\n", "utf-8")
+    assert g.gate_enabled() is True, "env=0 不得关掉已校准的门禁"
+
+
+def test_gate_enabled_defaults_on_without_state(tmp_path, monkeypatch):
+    from nsc.eval import gate as g
+
+    monkeypatch.setattr(g, "GATE_STATE_PATH", tmp_path / "nonexistent.yml")
+    monkeypatch.setenv("JUDGE_GATE_ENABLED", "0")
+    assert g.gate_enabled() is True  # 无校准状态文件：默认开
 
 
 def test_gate_state_file_fallback(tmp_path, monkeypatch):