Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It discloses only that the operation is read-only, with nothing about what 'local relationship context' contains, what happens when the email matches no contact, or any auth/data-source (local vs server) implications.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.