Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations provide readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, which already cover the safety profile. The description adds the 'third-party opinions' framing, which is useful context indicating the data's provenance. No contradictions with annotations. However, it doesn't detail limit behavior or pagination beyond schema defaults, so it adds modest but not rich context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.