diff --git a/tests/test_agent_state_dir_confinement.py b/tests/test_agent_state_dir_confinement.py
index d2487c298..ab05bab18 100644
--- a/tests/test_agent_state_dir_confinement.py
+++ b/tests/test_agent_state_dir_confinement.py
@@ -331,7 +331,9 @@ def test_allows_files_in_the_agent_workspace():
     (PERSONAL_UPLOADS_DIR,
      "indexed into personal docs by routes/personal_routes.py, and listed as "
      "an absolute path by manage_rag"),
-])
+# The directories live under a per-worker data dir, so they cannot be test ids:
+# xdist requires every worker to collect the same names.
+], ids=["uploads", "mail_attachments", "personal", "personal_uploads"])
 def test_allows_user_content_the_app_hands_to_the_model(directory, why):
     """Carving these out is not convenience. The app gives the model these
     paths and tells it to read them, so denying them breaks the feature."""