We just started using temporal.io and we were looking for a way to view a list of currently deployed/registered activities and how many of each are listening to their respective queues. We were looking through all the API calls in the client libraries and through the admin tool and there does not appear to be a way to see that information. We would like to be able to see this information through the web client or through an SDK.
This is not currently supported, but we have plans to add this in the future. I filed an issue for tracking.