diff --git a/tests/unit/test_contaminant_simulation_mcp.py b/tests/unit/test_contaminant_simulation_mcp.py
index a6bcfdf..7df8817 100644
--- a/tests/unit/test_contaminant_simulation_mcp.py
+++ b/tests/unit/test_contaminant_simulation_mcp.py
@@ -42,27 +42,29 @@ def context(monkeypatch):
     return scope, binding
 
 
-def test_replay_prediction_can_extend_past_cutoff_without_reading_future_observations(monkeypatch):
+@pytest.mark.parametrize("include_impact", [True, False])
+def test_replay_prediction_can_extend_past_cutoff_without_reading_future_observations(monkeypatch, include_impact):
     scope, binding = context(monkeypatch)
     worker = AsyncMock(return_value={"impact": {"affected_node_count": 2}})
     monkeypatch.setattr(analysis_service, "calculate_replay_contaminant_simulation", worker)
-    result = asyncio.run(query_service.execute_query(scope, binding, TOOLS["run_contaminant_simulation"], args()))
+    parameters = args(include_impact_coverage=include_impact)
+    result = asyncio.run(query_service.execute_query(scope, binding, TOOLS["run_contaminant_simulation"], parameters))
     assert result.origin == "synthetic" and result.data["result"]["impact"]["affected_node_count"] == 2
     assert "预测" in result.data_gaps[0]
     scope.connection.commit.assert_awaited_once()
     worker.assert_awaited_once()
+    assert worker.await_args.args[0].include_impact_coverage is include_impact
     assert worker.await_args.kwargs == {"network": "project", "username": "actor"}
     assert should_queue(TOOLS["run_contaminant_simulation"], args())
 
 
-@pytest.mark.parametrize("problem", ["future_start", "no_impact", "reader", "permission"])
+@pytest.mark.parametrize("problem", ["future_start", "reader", "permission"])
 def test_replay_admission_keeps_time_permission_and_reader_boundaries(monkeypatch, problem):
     scope, binding = context(monkeypatch)
     parameters = args()
     if problem == "future_start": parameters = args(start_time="2026-07-16T08:15:00+08:00")
-    if problem == "no_impact": parameters = args(include_impact_coverage=False)
     if problem == "reader": binding.purpose = "task_reader"
     if problem == "permission": binding.permission_cap.remove("scada.view")
     with pytest.raises(HTTPException) as caught:
         asyncio.run(query_service.authorize_query(scope, binding, TOOLS["run_contaminant_simulation"], parameters))
-    assert caught.value.status_code == (422 if problem in {"future_start", "no_impact"} else 403)
+    assert caught.value.status_code == (422 if problem == "future_start" else 403)