Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered structurally. The description adds one genuinely useful behavioral note – that calling it is a safe way to probe auth state – but says nothing about the shape of the returned user object, which matters because there is no output schema.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.