How to Actually Design an AI Agent: Tools and the Starting Loop (Part 2)

TL;DR The model matters, but tools matter at least as much. Weak tool descriptions are one of the easiest agent failures to diagnose, and one of the most common. Design the tools before the agent. If you cannot answer "what can this agent do that a general LLM cannot on its own?", you do not have an agent yet. Ship a small, focused loop with 2-3 well-described tools and a hard iteration cap. Watch traces. Iterate. In Part 1 I laid out the four levels of AI agents I keep seeing in production, and argued that most shipped "AI agents" are stuck on the lower rungs.