Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only declare readOnlyHint=false and openWorldHint=false, which tell the agent this mutates state; the description adds that the resulting layer is opaque but says nothing about whether the original layer is replaced, what happens to an existing background layer, or whether the operation is reversible. No destructiveHint is declared and the description does not compensate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.