Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds substantial context beyond annotations: it is read-only and 'writes nothing' (reinforcing readOnlyHint), it clarifies the tool does NOT submit, does NOT pull a repo, and the repo/source params are 'echoed back only.' That is exactly the kind of behavioral clarification that prevents miscalls on a wizard entry point.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.