diff --git a/CLAUDE.md b/CLAUDE.md
index 33d5b08..d1c9384 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -38,6 +38,12 @@ Ask before an action that uses much cloud budget.
   (`harness/task.py`). Teardown after each run with the ADT deletion API (`adt_client.py`, credentials in `.env`).
   Delete only objects with a run prefix. Clean up probe objects.
 - The model never sees delete/teardown. The proxy (`proxy.py`) has a tool whitelist and hides other runs' objects.
+- To wait for a background job, use its PID: `while kill -0 <PID> 2>/dev/null; do sleep 60; done`.
+  Do NOT use `pgrep -f <pattern>` in the loop: it also finds the loop's own command line, so the loop never ends.
+  The process name of a module run is `Python -m harness.<module>` (not `python3`); `pgrep -f "harness.pilot"`
+  without a loop gives the PID.
+- Start long jobs with `nohup ... &` from a separate line after `cd` (a `cd ... && nohup ... &` chain runs
+  in a subshell; the commands after it do not see the new directory).
 
 ## 4. Layout