Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries full responsibility for behavioral disclosure. It only says 'set' without specifying side effects (e.g., whether it mutates the session state, whether the sort persists, or what the response contains). No information about expected_version conflict handling or the result of a successful call is given. The description does not contradict annotations (since none exist), but it fails to disclose any behavioral traits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.