It's been blurry for a long time, FWIW. I have books on "Agents" dating back to the late 90's or early 2000's in which the "Intro" chapter usually has a section that tries to define what an "agent" is, and laments that there is no universally accepted definition.
To illustrate: here's a paper from 1996 that tries to lay out a taxonomy of the different kinds of agents and provide some definitions:
The technical difference between agents then and agents now are the fuzzy parameter mapping capabilities of LLMs, if used.
Scaling agent capability requires agents that are able to auto-map various tools.
If every different tool is a new, custom integration, that must be written by a person, then we end up where we are today -- specialized agents where there exists enough demand and stability to write and maintain those integrations, but no general purpose agents.
Ultimately, parameter mapping in a sane, consistent, globally-applicable way is the key that unlocks an agentic future, or a failure that leads to its demise.
Scaling agent capability requires agents that are able to auto-map various tools.
If every different tool is a new, custom integration, that must be written by a person, then we end up where we are today -- specialized agents where there exists enough demand and stability to write and maintain those integrations, but no general purpose agents.
Ultimately, parameter mapping in a sane, consistent, globally-applicable way is the key that unlocks an agentic future, or a failure that leads to its demise.