I have two agents that can build my configuration. I've set up two because I sometimes need to do two simultaneous builds.
How can I set build agent priorities to force TeamCity choose specific agent if both are idle and available?
Now it chooses agent randomly or by some unknown factors...
You can filter which agents are used but I'm not sure you can specify which idle to agent to use.
If you are worried about TeamCity using the fastest agent it should do this automatically.
The Teamcity documentation states the following.
You can specify that it uses a build agent using the Agent Parameters.
For example you can specify the build agent name (using "system.agent.name") or state that you want to only use build agents with a TeamCity CPU benchmark (say of 400) using: system.teamcity.agent.cpuBenchmark is more than 400.
Now it's possible to configure agent priorities with help of the plugin. Please enjoy ;)