Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden and it delivers: 'Retrieve' signals a safe read operation, 'with everything recorded about it' discloses the return scope, and the slug-permanence guarantee ('same slug names the same source across releases') is a genuine behavioral trait useful for citation workflows. It doesn't cover not-found error behavior, but for a one-parameter read tool that is a minor gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.