Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It states the action (open history) and return value (most recent answer), and gives a behavioral hint (prefer ID). But it does not disclose side effects (e.g., whether it switches the current context), error handling for missing or ambiguous identifiers, or prerequisites like browser state. This is adequate but not rich.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.