diff --git a/tests/test_adapter.py b/tests/test_adapter.py
index 68b1aee..0392eea 100644
--- a/tests/test_adapter.py
+++ b/tests/test_adapter.py
@@ -409,7 +409,7 @@ class TestAdapterDedupMergesSameModule:
 
 class TestAdapterRemoteStateKeyOverride:
     """P2-2 (v1.14, REQ-139): NOVA_REMOTE_STATE_KEY env var (P2 renamed from
-    ACDL_REMOTE_STATE_KEY; dual-read NOVA_* preferred, ACDL_* fallback until
+    NOVA_REMOTE_STATE_KEY; dual-read NOVA_* preferred, ACDL_* fallback until
     P5) overrides the default 'platform/terraform.tfstate' key in the emitted
     data terraform_remote_state block. This is the load-bearing correctness
     mechanism for the microservice L2 lifecycle (remote state points at the
@@ -417,8 +417,8 @@ class TestAdapterRemoteStateKeyOverride:
 
     def test_default_remote_state_key(self, tmp_path, monkeypatch):
         """When NOVA_REMOTE_STATE_KEY is unset, the default key is used."""
+        # P5 (REQ-164): ACDL_* fallback removed — NOVA_* only.
         monkeypatch.delenv("NOVA_REMOTE_STATE_KEY", raising=False)
-        monkeypatch.delenv("ACDL_REMOTE_STATE_KEY", raising=False)
         stack = {
             "resources": [
                 {"id": "s3", "type": "aws:s3:bucket", "module": "s3@1.0.0", "inputs": {"bucket_name": "test", "region": "us-east-1"}}
diff --git a/tests/test_route_halt_artifact.py b/tests/test_route_halt_artifact.py
index a8e3f1b..cd32442 100644
--- a/tests/test_route_halt_artifact.py
+++ b/tests/test_route_halt_artifact.py
@@ -14,8 +14,8 @@ from core.separation_of_duties import route_halt_artifact
 
 
 def test_route_halt_publishes_to_sns_when_arn_set(monkeypatch):
-    """With ACDL_SOD_HALT_TOPIC_ARN set, the SNS client receives the publish."""
-    monkeypatch.setenv("ACDL_SOD_HALT_TOPIC_ARN", "arn:aws:sns:us-east-1:000000000000:nova-sod-halt")
+    """With NOVA_SOD_HALT_TOPIC_ARN set, the SNS client receives the publish."""
+    monkeypatch.setenv("NOVA_SOD_HALT_TOPIC_ARN", "arn:aws:sns:us-east-1:000000000000:nova-sod-halt")
     sns_client = mock.MagicMock()
     route_halt_artifact("contract-123", "SEPARATION_OF_DUTIES_VIOLATION: x==y",
                         oncall_client=sns_client)
@@ -28,9 +28,9 @@ def test_route_halt_publishes_to_sns_when_arn_set(monkeypatch):
 
 
 def test_route_halt_falls_back_to_stderr_when_arn_unset(monkeypatch, capsys):
-    """Without ACDL_SOD_HALT_TOPIC_ARN, a stderr emission occurs."""
+    """Without NOVA_SOD_HALT_TOPIC_ARN, a stderr emission occurs."""
+    # P5 (REQ-164): ACDL_* fallback removed — NOVA_* only.
     monkeypatch.delenv("NOVA_SOD_HALT_TOPIC_ARN", raising=False)
-    monkeypatch.delenv("ACDL_SOD_HALT_TOPIC_ARN", raising=False)
     # Mock outbox_writer.write_event to avoid AWS calls.
     with mock.patch("core.outbox_writer.write_event", return_value=None):
         route_halt_artifact("contract-456", "violation", oncall_client=None)
@@ -41,8 +41,8 @@ def test_route_halt_falls_back_to_stderr_when_arn_unset(monkeypatch, capsys):
 
 def test_route_halt_outbox_fallback_writes_event(monkeypatch):
     """Without the SNS ARN, the outbox fallback writes a SEPARATION_OF_DUTIES_VIOLATION event."""
+    # P5 (REQ-164): ACDL_* fallback removed — NOVA_* only.
     monkeypatch.delenv("NOVA_SOD_HALT_TOPIC_ARN", raising=False)
-    monkeypatch.delenv("ACDL_SOD_HALT_TOPIC_ARN", raising=False)
     with mock.patch("core.outbox_writer.write_event") as mock_write:
         route_halt_artifact("contract-789", "sod violation", oncall_client=None)
         mock_write.assert_called_once()
@@ -54,7 +54,7 @@ def test_route_halt_outbox_fallback_writes_event(monkeypatch):
 
 def test_route_halt_sns_failure_falls_back_to_outbox(monkeypatch):
     """If SNS publish raises, the outbox fallback is used."""
-    monkeypatch.setenv("ACDL_SOD_HALT_TOPIC_ARN", "arn:aws:sns:us-east-1:000000000000:nova-sod-halt")
+    monkeypatch.setenv("NOVA_SOD_HALT_TOPIC_ARN", "arn:aws:sns:us-east-1:000000000000:nova-sod-halt")
     sns_client = mock.MagicMock()
     sns_client.publish.side_effect = Exception("SNS down")
     with mock.patch("core.outbox_writer.write_event") as mock_write: