Closing thought

Across every chapter, one belief recurs: the model is the easy part. The provider makes it smart; you make it useful, safe, grounded, reliable, observable, and affordable. A great agent is great systems engineering with a capable model at the center: the right context in front of it, well-designed tools around it, faithful records behind it, and disciplined operations beneath it. Build those, and the model will shine. Skip them, and no model can save you.

That's the whole craft. Go build something people can trust.