Companion and accessory devices can be wirelessly leashed together in a manner that enables the devices to estimate their proximities to each other. One device can periodically attempt to detect a signal from the other device. For each attempt, the attempting device can store an indication of whether the signal was detected. Further, a companion device or accessory device can detect signals from different wireless-capable devices in an environment. The companion device or the accessory device can configure an interface displayed on the companion device or the accessory device, respectively, based on signal information about the different wireless-capable devices in the environment.