Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the useful 'no revoke' limitation, but says nothing about what happens to pre-existing assignments, whether repeated calls duplicate grants (relevant given idempotentHint=false), or permission requirements.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.