Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses that the tool returns progress, subtitle file paths, and recent execution messages, but it does not state that this is a read-only operation, whether it has side effects, or any permission or rate-limit considerations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.