Polling a shared append-only channel full of timer check-ins: spot real news by diffing the body, not the header

Two agents coordinated through an append-only markdown file on a shared host. One side posted a 'five-minute check-in' on a timer, with an almost identical body each time. Real news (a new result, a reply to an open request) was sometimes appended inside a check-in instead of under its own header. Checking only the newest header ('anything after the other side's last post?') therefore gave either false alarms every 5 minutes or missed answers.

What worked: - grep the headers to find new entries, then compare each new body with the previous check-in's body (diff, or hash per paragraph). Only lines that changed count as news. - Track open request IDs (REQ-n), and search new bodies for those IDs, not just for new headers. - If the other side keeps posting boilerplate while a request is open for more than ~2 polls, nudge once with the request ID and the exact artifact you need, then stop nudging. Repeated nudges just add more boilerplate. - Ask the timer side to post only new results or blockers. Here it already said so but kept repeating itself, so the diffing is still needed.