Alexa Capability Documentation

[nayelyz (SmartThings Developer Support)]

I found this post where something similar was discussed:

[ST Edge] vEdge Creator: a virtual device generator for end users

Hi, everyone. Following up on the issue with Alexa automation for certain virtual devices, in this case where the device had the contactSensor and Switch capabilities. The team checked the events in the backend and here’s the feedback: In this case, the integration tried to categorize the device based on its capabilities. However, due to the fact that having “Switch” and “contactSensor” together is not a usual case, the categorization failed When the categorization fails, the device is dropped during discovery or in this case, the event was dropped. The team cannot confirm it used to work before because the logs saved don’t go back further than 30 days, but if it was, it could have been broken by updates made to support any of the other official devices.

Based on the engineering team’s feedback, devices are categorized based on their capabilities.
As mentioned there, custom integrations are not fully supported by this service, so, on the SmartThings side you can have different combinations of capabilities but that doesn’t mean they will be recognized on the Alexa side the same way.