Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the transparency burden. It discloses that the tool returns 'signed' announcement data and explicitly mentions 'non-goals', which is somewhat transparent. However, it does not clarify what 'signed' means operationally (e.g., requires verification, network fetch) or whether any side effects occur. It is a reasonable description of a read-only getter but could be more explicit about behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.