Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is known. The description adds behavioral context by listing the exact fields returned, which goes beyond annotations, but it does not cover edge cases like missing tickers or data latency. This is a meaningful but not exhaustive addition.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.