Create a watch (free)

Create a watch tied to your credit token: a filter over parcels/geography + change event types. It reports changes going FORWARD; poll it to receive (and pay per delta for) new changes. Managing watches is free. Body: { filter, event_types?, name? } where filter is { parcel_ids:[...] } | { canonical_ids:[...] } | { state_fips } | { county_fips, state_fips } and event_types is a subset of parcel.sold / parcel.owner_changed / parcel.permit_filed (default all). Parcel ids (1–500) are canonical state_fips:county_fips:parcel_id ids, parcel UUIDs, or bare parcel_ids that name exactly ONE served parcel; a bare id that names several parcels is refused (422, candidates listed). The watch is stored and matched on canonical ids; parcel_resolution reports how each input resolved.