Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Although annotations already declare readOnlyHint and idempotentHint, the description adds meaningful behavioral context: default open status and ordering, key requirements for certain filters, escrow funding for public credit listings, sealed proposals, and delayed publication of anonymized tapes. These are not derivable from the annotations or schema and materially affect caller expectations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.