diff --git a/SKILL.md b/SKILL.md
index 811187a..34aed2e 100644
--- a/SKILL.md
+++ b/SKILL.md
@@ -698,7 +698,11 @@ Scripts that know a project's layout stay in that project.
   merged-cut worktrees that a handoff had put off "until idle". C: fell to
   1.4 GB free during an operator flight, and a new checkout died mid-write.
   Operator: "you really gotta start cleaning up after yourself". Check free
-  space before creating a worktree.
+  space before creating a worktree. Remove only worktrees this session's agents
+  created, by name. Never sweep a root by path prefix. The same day's sweep
+  found another Self's live tree "clean and pushed", and
+  `git worktree remove --force` emptied it mid-build. "Clean" says nothing
+  about who is working in a tree.
 
 ## Adapting the pipeline