Harness Engineering 101: The LLM is the brain, the harness is the body

"Harness Engineering 101" is a 16-chapter educational series that explains how to build AI agents by understanding that an LLM serves as the "brain" while a harness—the program managing the conversation array sent to the LLM API—serves as the "body." The series teaches foundational concepts through practical Python examples, covering core challenges like context management, tool integration, caching, and safety guardrails that arise when building functional agents.