Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide safety traits (readOnly, idempotent, non-destructive). The description adds significant behavioral context: it discloses the source API, the return structure (key 'raw'), and the extractable fields (name, LEI, RIC, etc.), enhancing understanding beyond 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.