Build a monitor that watches while you sleep

The simplest useful agent is a watcher: it checks a source on a schedule, compares what it finds against a threshold you set, and pings you only when something matters. A marketplace for a parcel under your price, a county portal for a new permit or planning-commission item, a rent-comp feed for a shift. The skill is not the checking, it's the THRESHOLD and the SILENCE. A monitor that alerts on everything is noise you'll mute; one that alerts on nothing is broken. Two build rules keep it honest. First, the threshold is explicit and yours ('asking under $X/acre AND legal access stated'), so you can tune it. Second, and this is the one everyone skips, the empty and error cases must be loud: if the source returns zero rows or fails to load, the monitor says so, because a watcher that silently reads nothing and reports 'all clear' is the exact failure that lets a deal or a deadline slip past. Schedule it with Claude's Routines or a cron; ship the logic working first, the scheduling is the easy part.