Building the Agent vs Building the System

By now a pattern should be visible. The model is often the easiest part. The hard engineering is everything around it: permissions, state, APIs, retrieval, observability, evaluation, error handling, security, and integration with systems that were not designed with a language model in mind. A working demo needs the model. A working product needs the system.

This is good news for teams that already know how to build software. Most of the work is work you know. The new part is smaller than it looks, and it is contained in the boxes from chapter 15 where the model acts.