diff --git a/tests/test_note_usage.py b/tests/test_note_usage.py
index b57f6b3..d223e6d 100644
--- a/tests/test_note_usage.py
+++ b/tests/test_note_usage.py
@@ -9,6 +9,22 @@ from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
+
+@pytest.fixture(autouse=True)
+def _no_supersession():
+    """The auto-inject menu now asks which of its lines are superseded (#278).
+
+    That is a real database call on a path these tests exercise without one.
+    Stubbed to "nothing superseded" — the ordinary state — rather than hidden
+    behind a try/except in the product, which would make the code lie about
+    what it does. The label's own behaviour is covered in
+    tests/test_supersession_ranking.py.
+    """
+    with patch("scribe.services.plugin_context.superseded_ids",
+               AsyncMock(return_value=set())):
+        yield
+
+
 from scribe.services import note_usage
 from scribe.services.note_usage import (
     empty_usage,
diff --git a/tests/test_retrieval_scopes.py b/tests/test_retrieval_scopes.py
index 478edce..3f4fa6b 100644
--- a/tests/test_retrieval_scopes.py
+++ b/tests/test_retrieval_scopes.py
@@ -17,6 +17,22 @@ from unittest.mock import AsyncMock, MagicMock, patch
 import pytest
 
 
+@pytest.fixture(autouse=True)
+def _no_supersession():
+    """The auto-inject menu now asks which of its lines are superseded (#278).
+
+    That is a real database call on a path these tests exercise without one.
+    Stubbed to "nothing superseded" — the ordinary state — rather than hidden
+    behind a try/except in the product, which would make the code lie about
+    what it does. The label's own behaviour is covered in
+    tests/test_supersession_ranking.py.
+    """
+    with patch("scribe.services.plugin_context.superseded_ids",
+               AsyncMock(return_value=set())):
+        yield
+
+
+
 def _note(id=1, user_id=7, title="A note", note_type="note",
           is_task=False, task_kind="work"):
     n = MagicMock()
diff --git a/tests/test_services_plugin_context.py b/tests/test_services_plugin_context.py
index 82b96e1..e45c98e 100644
--- a/tests/test_services_plugin_context.py
+++ b/tests/test_services_plugin_context.py
@@ -3,6 +3,22 @@ from unittest.mock import AsyncMock, MagicMock, patch
 import pytest
 
 
+@pytest.fixture(autouse=True)
+def _no_supersession():
+    """The auto-inject menu now asks which of its lines are superseded (#278).
+
+    That is a real database call on a path these tests exercise without one.
+    Stubbed to "nothing superseded" — the ordinary state — rather than hidden
+    behind a try/except in the product, which would make the code lie about
+    what it does. The label's own behaviour is covered in
+    tests/test_supersession_ranking.py.
+    """
+    with patch("scribe.services.plugin_context.superseded_ids",
+               AsyncMock(return_value=set())):
+        yield
+
+
+
 def _rule(rid, title, topic_id):
     r = MagicMock()
     r.id, r.title, r.topic_id = rid, title, topic_id