In the Azure Digital Twin (ADT) limitation:
https://learn.microsoft.com/en-us/azure/digital-twins/reference-service-limits
there is a limitation on the "number of models within a single Azure Digital Twins instance".
My questions: how to count the number of models in ADT? what is counted as a single model in ADT?
You can get all the models by using the az CLI, there is a model list command that you can use. Alternatively, you can use any of the SDKs to do the same. I get the number of models by adding a JMESPath query to it:
az dt model list -n <adt-name> --query "length(@)"
This will only return the number of models.