Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations (destructiveHint, idempotentHint) the description discloses that skipped checks are never made up, that an in-progress check is cancelled, that failures are reported in 'failed', and that retrying is safe. This is rich behavioral context that goes well past the structured hints.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.