Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish read-only, idempotent, closed-world behavior, and the description adds meaningful context: results are staged from data-returning tools, each entry includes source tool, query parameters, timestamps, row count, schema, and truncation status. It does not cover auth or rate limits, but it goes well 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.