I’d argue there are 3 layers not 2. The model, the harness and the framework. The reason is the harness tends to carry the model runner, tool access and varying levels of deterministic control.

The framework sits on top of this and brings the rules, behaviors and further deterministic controls.

Or simply What, How, Who.

What: capabilities, access to model, APIs, tools, permissions, deterministic controls.

How: Workflows, policies, guidelines, guardrail and permission definitions, configuration of further deterministic controls (is generally checked in with the product)

Who: the agent/model roster, their roles, personalities