Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish that this is a safe read-only operation, and the description adds useful behavioral context: referenced definitions are included, generated value lists are summarized rather than enumerated, and validate_chart remains the authority. These details help an agent understand the tool’s limits and output character.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.