4 of the most confusing terms in AI, defined: Model: a blob of parameters, written during training. Does next-token prediction and nothing else. Stateless. Harness: everything around the model that turns it into an agent: tools, system prompt, context window management, etc. Environment: the world the agent acts on. Anything outside the harness that the agent perceives and acts on via tools. Agent: a model, harnessed, in an environment. --- Opus is a model. Claude Code and Claude Web are…