diff --git a/apps/device-host-agent/tests/conftest.py b/apps/device-host-agent/tests/conftest.py
new file mode 100644
index 0000000..2b91784
--- /dev/null
+++ b/apps/device-host-agent/tests/conftest.py
@@ -0,0 +1,11 @@
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def _humanize_disabled_by_default_in_tests(monkeypatch):
+    """Humanize defaults ON in production; tests default it OFF so existing
+    exact-coordinate assertions stay deterministic. Tests that want to
+    exercise humanize call ``monkeypatch.setenv("APEX_HUMANIZE_ENABLED", "true")``
+    in their own body, which overrides this fixture (test body runs after
+    fixture setup)."""
+    monkeypatch.setenv("APEX_HUMANIZE_ENABLED", "false")