Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered structurally. The description adds genuinely non-obvious context: secrets in the returned settings are replaced with [redacted], which tells the agent why credentials will appear masked and prevents pointless retries or workarounds. It stops short of describing the shape of the settings object.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.