Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries full burden for behavioral disclosure. 'Update multiple email records' implies a write/mutation operation but doesn't specify permissions required, whether changes are reversible, rate limits, error handling for partial failures, or what the response contains. For a batch mutation tool with zero annotation coverage, this is a significant gap in behavioral context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.