Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description goes well beyond them: periodic-refresh staleness, credential-derived account ID, refusal of cross-account queries, and interpretation rules for LOW confidence / identity_only_rows / literal_only_result. That confidence-semantics guidance is genuinely non-obvious context. Minor deduction because the return-envelope listing duplicates what the output schema likely already declares.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.