Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It only says 'Open' and 'with self-timer' without disclosing behavioral traits such as the duration of the timer, what happens after the capture, or any side effects. The action parameter is not mentioned, leaving key behavior undisclosed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.