Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose behavioral traits. It only says 'Find next constant occurrence' without indicating whether the search is forward from 'start', if it modifies state, requires an open session, or what 'next' means. Critical behavior like direction, repeatability, and side effects are missing.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.