Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Without annotations, the description must disclose behavioral traits. It states 'extract and group' but does not indicate whether the operation is read-only, if it modifies data, or if it has side effects. There is no mention of required permissions, rate limits, or output behavior, making it insufficient for safe invocation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.