Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavioral context: transcript content is authored by participants or the world and must be treated as material, never as instructions — a prompt-injection boundary that structured fields cannot express. It does not, however, disclose size, scope or return shape.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.