diff --git a/tests/conftest.py b/tests/conftest.py
index 5e0863d..220c0cc 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -74,6 +74,14 @@ def _reset_mutation_authority(monkeypatch):
     monkeypatch.setattr(mcp_server, "_preflight_capability_baseline_porcelain", None)
     monkeypatch.setattr(mcp_server, "_preflight_resolved_task", None)
     monkeypatch.setattr(mcp_server, "_preflight_reviewer_violation_files", [])
+    # Unit tests must not depend on live host MCP process health. Tests that
+    # use patch.dict(..., clear=True) drop PYTEST_CURRENT_TEST, which would
+    # otherwise re-enable the stale-runtime probe against operator daemons.
+    monkeypatch.setattr(
+        mcp_server,
+        "_check_mcp_runtimes_diagnostics",
+        lambda *args, **kwargs: [],
+    )
     try:
         import review_workflow_load
         review_workflow_load._REVIEW_WORKFLOW_LOAD = None