-You can add other tags to `THREAD_TAGS` as needed. Note that this is one way
-only; you need to explicitly remove the tag from all the messages in a thread to
-stop it from propagating again.
+You can add other tags to `THREAD_TAGS` as needed. Note that this is
+one way only; you need to explicitly remove the tag from all the
+messages in a thread to stop it from propagating again. See
+[notmuch-search-terms](https://notmuchmail.org/doc/latest/man5/notmuch-hooks.html)
+for discussion of `thread:{}` queries.