By default, builds of this project may be executed on any build agents that are available and configured to accept new builds.

When this option is checked, you have the possibility to ensure that builds of this project only occur on a certain agent, or set of agents.

For example, if your project should only be built on a certain operating system, or on machines that have a certain set of tools installed, or even one specific machine, you can restrict this project to only execute on agents that that meet those criteria.

The help text for the Label Expression field, shown when this option is checked, provides more detailed information on how to specify agent criteria.