diff --git a/pyproject.toml b/pyproject.toml
index fda17ed..84f6a0d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -116,3 +116,8 @@ omit = [
 
 [tool.coverage.report]
 show_missing = true
+
+[tool.pytest.ini_options]
+# pytest retains all temp files from the last 3 test suite runs by default.
+# Keep only ones for failed tests to avoid filling up a disk.
+tmp_path_retention_policy = "failed"