Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses exactly what information the tool returns (source, date, licence, citation) and implies a read-only nature via 'Read this.' It doesn't mention side effects, but for a static provenance lookup, this is sufficient and does not contradict any structured data.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.