Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose behavioral traits (e.g., pagination, sorting, read-only nature). It only says 'List time entries', omitting that it supports pagination via offset/limit and sorting via sort parameter, which are evident only from the schema. No mention of rate limits or side effects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.