Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=true; the description adds nothing about what the action does, what it mutates, whether it requires specific permissions, or that it is non-idempotent so retries may duplicate work. For a write tool the description should at least name the supported action types.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.