Tools

A tool definition has two readers with opposite needs. The model reads the name and description as natural language and decides whether to call. The host and the server read the schemas as a machine contract and decide whether a call is valid, whether its result is well formed, and whether a person must approve it. The failures worth studying come from serving one reader and forgetting the other: a schema that validates perfectly behind a description no model can use, or a carefully written description whose server answers mistakes with errors the model never sees.