Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations cover only readOnlyHint/openWorldHint, so the description earns credit by disclosing that counts are live, that optional per-product fields (colors, materials, sizes, gender, line) are dropped when the source lacks them, and that a truly empty result returns an empty products list rather than an error. These are real data-completeness guarantees an agent couldn't infer from structured fields.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.