A common way to deploy services these days is with minimal containers which contain just enough information to run one process, and you often deploy lots of these things in different contexts.
It would be really cool if you could configure a wavefront proxy to add additional tags to each metric that it receives. For example, if I deploy container 'Foo' in two different services, and Foo emits metrics, I have to pass some additional context to Foo so that it can create additional metrics tags such as "service=some_service". I currently run one wavefront proxy per isolated service, and if I could have the proxy append "service=some_service" to each metric it receives, I don't have to pass that context to the container anymore.
It would be likewise useful to add agent/source tags as well. For instance, if I've got two wavefront proxies in some big environment, I'd like to assign a source tag to each automatically, so that in the future, meta-metrics are easy to correlate and query. Right now, I have to find all the relevant sources or agents in the UI and manually give them a tag.