Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Return the manifest' – it does not mention potential errors, authentication requirements, rate limits, or what the manifest contains. The read-only nature is implied but not explicitly stated beyond the verb.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.