THE ANATOMY OF A PRODUCTION HARNESS (COMPONENT MAP)

THE TOOL REGISTRY The tool registry is the catalog of available tools and their permissions. You met tools in Chapter 7, and Part Four spends five chapters on them. For now, the key idea is that the harness keeps one organized list of every tool the agent could use. For each tool the registry records its name, a plain description the model can read, the shape of its inputs and outputs, what permission it requires, and which piece of code actually runs it. The word dispatch means sending a request to the right handler. When the model says, "Please run the tool called read_file," the registry is what finds read_file in the catalog and hands the request to the correct code. A registry is like the menu and the kitchen assignments of a restaurant together. The menu tells diners what is available, and the assignments tell the kitchen who prepares each dish. Without a registry, tools get wired into the loop one at a time, with special cases everywhere, and adding a new tool means editing many places.