This is a simple feature that is not known very well and deserve a blog post. Sometimes you want to queue a build to a specific agent in a queue and this can be simply done using agent.name as a demand.
Demands are simple key/value pairs that allows the build engine to choose compatible agents and each agent automatically have a couple of capability to store computer name and agent name (they can be different)
Figure 1: Capability of agentes, computer name and agent name are automatically present
This allows you to use one of them if you want to run a build on a specific machine, just queue the build and use the demands tab to add agent.name or agent.computername demands.
Figure 2: Choosing specific agent at queue time with agent.name capability
If you specify a name that is not valid you will get a warning, if the queue contains that specific agent the build will be queued and will be executed only by that agent.
This technique is useful especially if you add a new agent and want to trigger some specific build on it to verify if it has all the prerequisite ok.