Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds that it returns 'metadata and definition', which gives a bit more insight into the response content, but it does not disclose any additional behaviors such as error handling, permissions, or output details. Since annotations handle safety, the description adds limited but non-trivial context, so a 3 is appropriate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.