Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, but the description goes further by revealing the external API mechanism (Gemini with Google Search grounding, 'a real, cited web search'), the cost model ('billed per query'), and the rate limit ('a few calls per day per user'), which are critical behavioral traits not captured in the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.