Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the description's burden is low. The description adds context about matching behavior (case-insensitive, trimmed, no fuzzy matching) and pricing. However, it does not elaborate on ranking criteria or pagination beyond what the schema already provides for the limit parameter.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.