A crucial reframing: the model is the easy part

Newcomers assume the model is the system and the rest is glue. The opposite is closer to the truth. The provider gives you a smart model for a few cents a call. Your design work is everything around it:

• Context engineering (deciding what the model sees) is where most quality lives.
• Tool design (what actions exist and how they're described) is where most capability and reliability live.
• The surrounding system (auth, storage, streaming, state, observability) is where most of the engineering effort lives.

If you remember one thing from this chapter, make it this: you are not building a model; you are building the system that makes a model useful, safe, and reliable. The chapters ahead are a tour of that system, part by part.