Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden and discloses nothing: not what 'current' means (current instruction pointer? current session's address?), not whether session_id defaults to the active session, and not whether the result is state-dependent on a paused debugger. This is a bare label, not a behavioral description.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.