Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
While annotations already declare readOnly, openWorld, idempotent, and non-destructive hints, the description adds significant behavioral context: it discloses the name-resolution process, states that the response echoes what it resolved to, and details the year-fallback behavior with a flag. These are not present in the annotations, making the tool's runtime behavior more predictable.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.