Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only give the generic readOnly=false/openWorld=true/destructive=false profile, so the description carries real weight: it discloses that the tool is machine-generated, the date boundary (2020) that switches between the contemporary and deep-history longitudinal models, and that richer output requires opting in via include. It does not cover auth, determinism, or latency, but the model-selection disclosure is genuinely useful and non-obvious.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.