diff --git a/.gitignore b/.gitignore
index 013b7bc..d3f856f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,3 +23,4 @@ video/auth.*
 *.mp4
 
 r5-java/tmp
+property-data
diff --git a/pipeline/local_temp.py b/pipeline/local_temp.py
new file mode 100644
index 0000000..d2cfbc4
--- /dev/null
+++ b/pipeline/local_temp.py
@@ -0,0 +1,25 @@
+"""Repo-local temporary directory helpers for pipeline scripts."""
+
+from pathlib import Path
+import os
+import tempfile
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+LOCAL_TMP_DIR = REPO_ROOT / ".tmp"
+_TEMP_ENV_VARS = ("TMPDIR", "TEMP", "TMP")
+
+
+def local_tmp_dir() -> Path:
+    """Return the repo-local temp directory, creating it if needed."""
+    LOCAL_TMP_DIR.mkdir(parents=True, exist_ok=True)
+    return LOCAL_TMP_DIR
+
+
+def configure_tempfile_defaults() -> Path:
+    """Point stdlib and subprocess temp defaults at the repo-local temp dir."""
+    temp_dir = local_tmp_dir()
+    temp_dir_str = str(temp_dir)
+    for env_var in _TEMP_ENV_VARS:
+        os.environ[env_var] = temp_dir_str
+    tempfile.tempdir = temp_dir_str
+    return temp_dir