diff --git a/scripts/run_soxl_core_only_p3_isolated.py b/scripts/run_soxl_core_only_p3_isolated.py
index aa60aa3..fa69b68 100644
--- a/scripts/run_soxl_core_only_p3_isolated.py
+++ b/scripts/run_soxl_core_only_p3_isolated.py
@@ -67,6 +67,10 @@
     "market_regime_control_enabled",
     "market_regime_control_applied",
 )
+# Candidate wrappers may explicitly extend this finite set only when their
+# frozen P2 config has a separately bound redirect asset.  The default keeps
+# the legacy v3/v4 SOXX-only contract byte-for-byte compatible.
+ALLOWED_VOLATILITY_DELEVER_REDIRECT_SYMBOLS = frozenset({"SOXX", None})
 
 
 class SoxlCoreOnlyP3IsolatedRunnerError(ValueError):
@@ -309,7 +313,8 @@ def _summarize_source_decision(decision: object, *, as_of: datetime) -> dict[str
         or summary["base_blend_tier"] not in {"full", "mid", "defensive"}
         or summary["active_risk_asset"] not in {"SOXL", "SOXX", "SOXX+SOXL"}
         or not isinstance(summary["blend_gate_volatility_delever_triggered"], bool)
-        or summary["blend_gate_volatility_delever_redirect_symbol"] not in {"SOXX", None}
+        or summary["blend_gate_volatility_delever_redirect_symbol"]
+        not in ALLOWED_VOLATILITY_DELEVER_REDIRECT_SYMBOLS
         or summary["market_regime_control_enabled"] is not False
         or summary["market_regime_control_applied"] is not False
     ):
diff --git a/scripts/run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py b/scripts/run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py
index c4d29ff..8d2b6ea 100644
--- a/scripts/run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py
+++ b/scripts/run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py
@@ -31,6 +31,7 @@ def _core():
     module.P2_UES_UV_LOCK_SHA256 = P2_UES_UV_LOCK_SHA256
     module.P2_CANDIDATE_ID = P2_CANDIDATE_ID
     module.P2_CONFIG_SHA256 = P2_CONFIG_SHA256
+    module.ALLOWED_VOLATILITY_DELEVER_REDIRECT_SYMBOLS = frozenset({"SOXX", "BOXX", None})
     module.__file__ = str(Path(__file__).resolve())
     return module
 
diff --git a/tests/test_run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py b/tests/test_run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py
index 63c19dd..a016a1d 100644
--- a/tests/test_run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py
+++ b/tests/test_run_soxl_core_only_v5_longterm_drawdown_p3_isolated.py
@@ -2,7 +2,9 @@
 
 import importlib.util
 import json
+from datetime import UTC, datetime
 from pathlib import Path
+from types import SimpleNamespace
 
 import pytest
 
@@ -36,3 +38,35 @@ def test_v5_runner_installs_its_own_identity_and_rejects_v4_candidate() -> None:
     assert module.validate_p2_candidate(json.loads(V5_CANDIDATE.read_text(encoding="utf-8")))["candidate_id"] == CANDIDATE_ID
     with pytest.raises(Exception, match="identity mismatch"):
         module.validate_p2_candidate(json.loads(V4_CANDIDATE.read_text(encoding="utf-8")))
+
+
+def test_v5_runner_accepts_its_frozen_boxx_delever_redirect_without_relaxing_v4() -> None:
+    module = _module()
+    v5_core = module._core()
+    v4_script = Path(__file__).parents[1] / "scripts" / "run_soxl_core_only_free_split_close_p3_isolated.py"
+    spec = importlib.util.spec_from_file_location("run_soxl_core_only_free_split_close_p3_isolated", v4_script)
+    assert spec and spec.loader
+    v4_module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(v4_module)
+    v4_core = v4_module._core()
+    decision = SimpleNamespace(
+        positions=tuple(
+            SimpleNamespace(symbol=symbol, target_value=weight)
+            for symbol, weight in (("SOXL", 0.0), ("SOXX", 25_000.0), ("BOXX", 75_000.0))
+        ),
+        diagnostics={
+            "blend_tier": "full",
+            "base_blend_tier": "full",
+            "active_risk_asset": "SOXX",
+            "blend_gate_volatility_delever_triggered": True,
+            "blend_gate_volatility_delever_redirect_symbol": "BOXX",
+            "market_regime_control_enabled": False,
+            "market_regime_control_applied": False,
+        },
+    )
+
+    result = v5_core._summarize_source_decision(decision, as_of=datetime(2026, 1, 2, tzinfo=UTC))
+
+    assert result["diagnostics"]["blend_gate_volatility_delever_redirect_symbol"] == "BOXX"
+    with pytest.raises(v4_core.SoxlCoreOnlyP3IsolatedRunnerError):
+        v4_core._summarize_source_decision(decision, as_of=datetime(2026, 1, 2, tzinfo=UTC))