Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations are absent, so the description carries the full burden for behavioral disclosure. 'Multiply two numbers' accurately describes the core operation, but does not disclose edge cases, error handling, or return behavior. However, for a trivial arithmetic operation, this minimal description is acceptable and not misleading.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.