Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Despite annotations already covering readOnly/idempotent/non-destructive, the description adds substantial behavior: page size (25 default, 50 max), alphabetical sort by key, 500-character value truncation, and the nextSkip paging contract. This is exactly the operational detail an agent needs to page correctly.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.