Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context beyond annotations by clarifying that the catalog is served live via Gutendex and that the D1 counts are local indexed-corpus statistics, including the last refresh timestamp. This helps the agent understand what data source and freshness semantics to expect.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.