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. While 'Update' implies a write/mutation operation, the description doesn't mention permission requirements, whether updates are atomic or partial, error handling for failed updates, rate limits, or what happens to unspecified contact properties. This is inadequate for a mutation tool with zero annotation coverage.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.