last_activity() is the whole trigger: the PM acts iff the newest thing in a thread was not written by it. It found that newest comment by comparing Gitea's RFC 3339 created_at STRINGS, which is only correct while every offset is identical — true today, silently wrong after a server timezone change, and the failure would be the PM answering its own last comment forever. The comments endpoint returns them in creation order, so the last element IS the newest. Using that removes the dependency entirely. Found by self-review, before anything ran. Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>