Agents are one-way connectors that can be scheduled to import contacts from a variety of source systems, such as Active Directory, SharePoint, Exchange and others into a PeopleSync address list. An address list will always reflect the state of the source system. There is no way to transfer data back to the source system. Changes made to an address list by parties other than the agent will be overwritten during the agent's next run.
Agents always import data from a single source system to a single address list. An agent cannot import data into an address list that is already served by another agent.
The PeopleSync Service runs the agents at the times defined in their schedules. Only enabled agents targeting an enabled address list are executed.