Module model 

The chat-model abstraction the agent loop runs against.

Decoupling the loop from a concrete client means: (a) the loop is unit- testable with a scripted mock — no network; (b) any backend (the real LlmClient, a local model, a replay harness) plugs in by implementing one method.

Traits

ChatModel

Anything that can turn a chat-completion request into a response.