The /summary PR command results in an automatic email sent to the mailing list formatted as if it were a regular comment, which can be confusing to the readers of the mailing list. For an example, see the PR command:

https://github.com/openjdk/jdk/pull/125#issuecomment-691042198

and the resulting email:

https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2020-September/040017.html

Perhaps some context information could be added, e.g. "updated summary".