Field noteDevices at the edge
Talking to door controllers: what ISAPI teaches about typed outcomes
A boolean cannot carry what an access-control panel answers. Three measured facts (a failed write with HTTP 200 and no status, an acknowledged write that changed nothing, a reused digest nonce the panel refused) turned a 27-member interface whose every write returned a boolean into a closed set of typed outcomes, a classification order, a read-back rule and a fresh challenge per request; asking which way a door fails added a deadline on anything that unlocks one.