Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description still conveys useful behavioral traits: 'append-only' implies the data is immutable and read-only, and 'every publish' scopes the content. However, it says nothing about volume (an unbounded log of every publish with no pagination parameters), response format, or whether the Merkle root is a separate field — real risks for a zero-parameter call.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.