Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations include readOnlyHint=true, so the description correctly implies a non-destructive operation. It adds behavioral context by specifying the output (word frequencies) beyond the annotation. However, it does not address edge cases like punctuation or case sensitivity.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.