Since the beginning with CacheBox, I've always had this idea that the service should be able to adjust itself to accommodate whatever resources are available, independent of the requests from the agents. So if an agent requests placement in the Cluster context and there isn't any cluster storage available, the service should automatically downgrade to the next available context, specifically the server context.
I just realized today while testing integration with DataFaucet that this wasn't actually working, so I had to fix that and it also required a modification to the CacheBoxAgent.cfc. So the service is now up to version 0.9.8 and the Agent is up to version 1.3. If you have an agent in your distribution, you should update it.
So now if you have an agent that requests the cluster context and there isn't any cluster storage then when you view the agent list, that agent will appear in the server context instead. The detail for the agent however will show two lines - context and requested context, indicating that the agent has been automatically downgraded to another context. If it hasn't been downgraded, then it won't show the "requested context" line in the detail.