DESIGNING GOOD TOOLS

LEARNING GOALS By the end of this chapter you will be able to write clear tool names and descriptions, design minimal composable tools, craft self-correcting error messages, explain idempotency, and apply rate limits. A TOOL IS A USER INTERFACE FOR A MODEL When you design a phone app, you think about how a person will understand and use it. When you design a tool, the user is a model. The model cannot ask a coworker what a tool means. It has only the name, the description, and the schema in front of it. So a good tool is one that a smart but literal-minded newcomer, who has never seen your system, could use correctly on the first attempt. Everything in this chapter flows from that idea.