Minecraft wiki entry for Agent, associated text: The agent is seen in the official image of Education Edition.
The agent is the only mob exclusive to Education Edition. Bedrock Edition also contains resources for the mob, however, the mob is unusable, and invisible in game. By installing Code Connection, it is possible to use in Bedrock Edition on Windows.
On the free 10th-anniversary map that @BlockworksYT released, there is a puzzle in the "Library" area that involves controlling the Agent with glazed terracotta. On the Bedrock version of the map, the agent is added in as a new mob, while on Java, it is an armor stand with remodeled infested chiseled stone bricks on its head.
The agent spawn egg can be obtained with /give @s spawn_egg 1 56. However, when spawned via the spawn egg it is completely invisible.