Someone just explained the entire agent stack - harness, loop engineering, evals, LLM ops, tracing - in 19 minutes.

It's clearer than most $500 courses, and it's free.

harness → the structure around the model. loops → why the agent keeps going. evals → the "no" that catches it when it's wrong. tracing → how you find what actually broke.

That's the whole machine the article below breaks down, drawn out in one sitting.

Watch it first to see the shape of it - then read the guide below to actually build one.