Session entities are defined on a session ID level, which allows for specific entities to be tied to a user and their session. This means that session entities extend or replace a developer entity at the user session level. A user's session is the conversation they have with your agent from start to finish.
For example, if your agent has a
@pets entity that includes "dog" and "cat", that entity could be updated to include "bird" or "fish" depending on the information your agent collects from a user. The updated session entity would have the "bird" or "fish" entry for the rest of the conversation with your user.