What is an Agent?

A WebID is specified as an HTTP URI that defines an Agent.

But an Agent itself is not specified.

Originally it comes from FOAF:

http://xmlns.com/foaf/spec/#term_Agent

"The Agent class is the class of agents; things that do stuff. A well known
sub-class is Person, representing people. Other kinds of agents include
Organization and Group.

The Agent class is useful in a few places in FOAF where Person would have
been overly specific. For example, the IM chat ID properties such as
jabberID are typically associated with people, but sometimes belong to
software bots."

But in the 20 years since FOAF started Agent now means more things.

How do we specify it for the modern world?

1. Should we use OWL to do sameAs or to subclass?
2. Should a device be an Agent?  Henry is known for saying a hammer is a
device but not an agent
3. Is a Group considered an Agent

Agent needs to be defined in order to define WebID.

I'd like come up with some RDF that models this, any ideas?

Disclaimer:  there may be some in the group of the opinion that Agent
should NOT be specified or defined.  If, so I would ask you to start a NEW
thread making that case, as I'd like this one to try and understand how an
Agent is defined.

I believe the baseline should be foaf:Agent -- should be add more?