When I first started looking seriously at AI engineering, I thought the main problem would be choosing the right model. GPT, Claude, Gemini, open-source models, context windows, benchmarks, reasoning ability… But after building with them for a while, I started noticing something. The model is often not the hardest part. The difficult part is everything around it. You can have an extremely capable model and still build a terrible AI system. For example, imagine an AI support a...