What is the relationship between LLMs, Reasoning Models, and Agent Harnesses?

The reasoning model is the engine, and the agent harness is the software around it. Using a go-kart analogy, I explain how they fit together and why understanding the underlying LLM still matters. An excerpt from my reasoning model series: https://www.youtube.com/watch?v=Kh9mqTzjuEQ&list=PLfrHAQCRxtUs&index=1 Article on coding an agent harness: https://magazine.sebastianraschka.com/p/components-of-a-coding-agent