Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations provide readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true, which already inform the agent this is a safe, non-destructive, repeatable read operation. The description adds minimal value by implying it's a GET request, but doesn't disclose any additional behavioral traits like rate limits, authentication needs, or what specifically happens when invoked. No contradiction with annotations exists.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.