Agent Is Not the Model: why conflating LLMs with agent systems leads to poor architecture

An essay by Joe Wright argues that developers mistakenly conflate the AI model with the agent system it operates within, producing brittle architectures when building agentic applications. The post distinguishes between the model, the agent loop, the tool layer, and the orchestration layer as separate concerns. It advocates treating model selection as a late-binding decision rather than a core architectural constraint from the start.