Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. It clearly indicates this is a read-only informational tool that returns provenance metadata, and implies no side effects or destructive operations. It could explicitly state 'read-only' or describe the return format, but the intent is clear.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.