Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses the return values (depth, field count, list multipliers, risk level) and interprets CRITICAL as 'should be rejected', which is valuable behavioral context. It doesn't mention side effects, but 'Analyze' implies a non-destructive operation, and the return description is sufficient for this simple tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.